• Scientists are uncovering promising links between specific parts of our DNA and a range of disorders such as anxiety, depression, and obsessive-compulsive disorder.
• As with any disease, having certain genes or mutations in those genes doesn't mean you'll go on to develop the disorders, but it may play a key role.
• The research also helps highlight the biological underpinnings of mental illness, something that could help with the development of better treatments.

When you fall and break a bone, an X-ray shows the crack. There's no equivalent diagnostic for disorders of the brain — a shortfall that's made it difficult for millions of people with conditions ranging from anxiety to obsessive-compulsive disorder to get treatment.

A spate of new research may change that. In a handful of recent studies, scientists have identified what they believe to be some of the most reliable genetic hallmarks of mental illness, a discovery that would transform our current approach to treating the disorders. If we can better understand the genes that influence psychiatric diseases, we can design treatments that accurately target the part of the brain that they appear to effect.

"Beyond giving us so much data to explore, being able to show that depression is a brain disease, that there is biology associated with it, I think that's really critical,"Roy Perlis, the director of the Center for Experimental Drugs and Diagnostics at Massachusetts General Hospital, told Business Insider in 2016. "These are brain diseases, like any other. They're not someone's fault."

The latest research suggests that our DNA may play an outsize role in psychiatric disease. As far as diseases go, mental illnesses are among those that are the most likely to be passed down from parent to child, a finding only recently illuminated by decades of research. 

"Genetics plays a very big role in your risk of getting these diseases," Elinor Karlsson, a geneticist at the Broad Institute of MIT and Harvard University, told Business Insider. 

Still, looking at someone's genome alone will probably never be enough to determine if they'll go on to develop a psychiatric disease — other factors, including environmental factors like severe stress, play a strong role too. But scientists are discovering more and more clues that suggest that the key to discovering new treatments for mental illnesses will center on a deeper dive into our DNA.

"We need to go after this genetic component," Karlsson said.

In the summer of 2016, Perlis used data from 23andMe to pinpoint 17 genetic variants linked with major depressive disorder. But Perlis and 23andMe aren't the only ones making progress in this arena. Earlier this month, researchers at the University of Massachusetts and the Broad Institute identified four genes linked to obsessive-compulsive disorder (OCD), a chronic condition characterized by uncontrollable repetitive thoughts and behaviors. 

'People who have OCD are more likely to have these changes in these genes'

Hyun Ji Noh, a geneticist at the Broad Institute, has read lots of studies showing a link between OCD and genetics. Despite all this promising research, none of the existing papers came to any definitive conclusions about which genes seemed to be tied to the disorder.

So for her latest study, published earlier this month in the journal Nature Communications, she decided to try a different tack.

Instead of just focusing on human DNA, which in the other studies had yielded limited results, she looked at multiple sets of genes — and not just from humans. 

"There are a lot of naturally occurring dog diseases — especially psychiatric diseases — that are very similar to human diseases,"Hyun Ji Noh, a geneticist at the Broad Institute and the lead author on the study, told Business Insider. "So to me it was sort of natural to put dog studies in the context of human disease."

Noh's paper looked at hundreds of genes that had been implicated in psychiatric disease in dogs, mice, and people.

In humans, the researchers found 608 genes. To find out which of these 608 genes was actually tied to OCD, Noh compared what they looked like in hundreds of people with and without the disorder. By the end of the analysis, just four genes emerged that showed up repeatedly in mutated form in people with OCD. 

In these four genes, "a lot of mutations kept showing up for OCD patients but not in the healthy individuals," Noh said.

In other words, these four genes likely play a key role in the biology of the disorder. Still, having a mutation in one of these four genes doesn't necessarily mean you'll go on to develop OCD.

"We know people who have OCD are more likely to have these changes in these genes. But this is one of potentially 100 things that will determine if you have OCD," said Karlsson, who also worked on the paper. "It's complicated," she said.

Chasing 'depression genes'

Like OCD, researchers say depression is influenced heavily by our DNA. But unlike OCD, it's fairly common, occurring in an estimated 16.1 million Americans. Current treatments for depression haven't changed much since the 1950s, and they don't work for everyone.

So, in an effort to find out more about what exactly causes the illness, researchers published a paper in the summer of 2016 in the journal Nature Genetics in which they pinpointed 17 genetic variations, or tweaks in particular genes, that appear to be tied to major depressive disorder, the most debilitating form of the disease that's currently the leading cause of disability worldwide.

The researchers got their data from personal genomics company 23andMe. 

Using data from more than 75,600 people who told the company that they'd been clinically diagnosed with depression and more than 231,700 people who reported no history of depression, Perlis and his team were able to identify 17 areas on DNA that appear to be linked with depression. They also found some ties between these areas and those which have been previously identified as possibly playing a role in other psychiatric disorders, such as schizophrenia.

Scientists have been looking for such genetic hallmarks of depression for years. And while some, like a 2013 study in the journal The Lancet and a 2015 paper in the journal Nature, have yielded promising clues, none have been able to spot any precise, reliable genetic markers of the disease.

At least not until now.

"My group has been chasing depression genes for more than a decade without success, so as you can imagine, we were really thrilled with the outcome," Perlis said.

The hope is that identifying these watermarks in our DNA — tiny areas on genes where high amounts of variation tend to occur among individuals — will help us better understand how genetics and behavior interact to influence disorders like depression.

Still, Perlis said, "this is really just the beginning. Now the hard work is understanding what these findings tell us about how we might better treat [these disorders]."

SEE ALSO: Scientists came to a fascinating conclusion after looking at the DNA of thousands of people with depression

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Somewhere in Baltimore, volunteers are gulping capsules filled with GMOs—gene-modified E. coli bacteria, to be precise.

Synlogic of Cambridge, Massachusetts, the company behind the unusual study, is testing what it calls “synthetic biotics,” or bacteria engineered to carry out specialized jobs in a person’s stomach.

Inside the pills are E. coli engineered to sop up ammonia inside the gut of people who can’t get rid of it fast enough. The study signals how genetic engineers are hoping to harness the microbiome, as the trillions of microscopic organisms that dwell within you are known.

The drug is designed to help people suffering from disorders of the “urea cycle.” That’s the metabolic flywheel inside your liver that gets rid of excess nitrogen. For people whose urea cycles are faulty, excess nitrogen turns into ammonia, just like what’s under your kitchen sink, and just as hazardous.

Though the condition is rare, for some people it’s serious enough to require a liver transplant.

This study, which began in June, doesn’t yet involve any sick patients. Instead, it’s a safety trial. The volunteers taking the drug collect a fee for swallowing GM germs to advance knowledge. They have to live in a testing facility for as long as three weeks so technicians can monitor them and collect their poop for DNA analysis.

Of the 50 people the trial is meant to study, Synlogic CEO J.C. Gutierrez-Ramos says “many” have already taken the new GMO pill. Others, picked at random, have gotten a placebo. The trial is being carried out at one hospital in Maryland.

The drug represents a concrete application of synthetic biology, which is the idea of engineering an organism’s metabolism to produce fuel, drugs, perfumes, or other chemicals. Previously, a company called ActoGenix undertook studies in Europe of a GM version of the bacterium Lactococcus lactis that it had altered so it released a protein drug. In the U.S., Marina Biotech also carried out a small safety test of anti-cancer bacteria, also genetically modified.

The U.S. Food and Drug Administration, which considers such drugs to be “live biological products,” this summer fast-tracked Synlogic’s application to try it on people. Gutierrez-Ramos says Synlogic will know if it’s safe by December and hopes to start up studies in actual patients next year.

SEE ALSO: A single gene in E. coli bacteria could hold clues for extending the human lifespan

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NOW WATCH: Meet the three women who married Donald Trump

• Morehouse College professor Dwann Davenport dared students to make a music video about anything from her biology class for extra credit.
• Julien Turner, who's part of a filmmaking duo, took up the challenge.
• He made up a poignant rap about mitosis and meiosis called "XY Cell Llif3" and starred in a music video about it.
• It's a take on "XO Tour Llif3" by Lil Uzi Vert.
• It's gone viral on Twitter, with more than 75,000 retweets.
• "I never turn down extra credit!" Turner told INSIDER in a Twitter direct message "A music video was right up my alley since I'm a filmmaker ... This is the one that happens to blow up."
• Watch it below.

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Getting your own DNA tested is so last year.

Now you can get a peek inside the genetic makeup of your dog. The method gives a rough estimate (it's not a perfect science), but it offers some intriguing insight for people who may have no idea what breed their best friend comes from.

The purpose of a dog DNA test is "to identify the breed or breed composite, which can be quite helpful information," Urs Giger, a veterinary clinician and researcher at the University of Pennsylvania's School of Veterinary Medicine, told Discover.

In other words, you can learn a lot with a dog DNA test — but like any other DNA test, there are some limits to the accuracy of the results.

I gave it a shot with my family dog, a mixed-breed rescue pooch named Izzie who we adopted from a Golden Retriever shelter in Los Angeles when I was a kid. Here's what I learned.

DON'T MISS: There's new evidence of how our DNA shapes depression and other disorders like it

SEE ALSO: I tried the popular Silicon Valley diet credited with boosting energy and prolonging life — and I can see why people are obsessed

This is Izzie. When I adopted her over a decade ago, I was told she was a mixed-breed golden retriever.

She was only a year old at the time, so no one knew how big she'd get (most goldens reach their full size, about 60 lbs., around age 2) or how she'd behave. Our veterinarian told us she was likely a (smallish) golden retriever mutt.

But Izzie stayed roughly the same size, and we stayed curious about her heritage. Now 15 years old, she's friendly and loyal.

Most people get dog DNA tests so they can find out what kind of behavioral traits to expect — golden retrievers tend to be loyal and good with kids, for example, while dalmatians are super active and generally make good guard dogs.

Source: American Kennel Club

When I got the chance to test her DNA, I seized it. There were several options, but I picked the Wisdom Panel DNA test developed by MARS Veterinary, the world's largest pet healthcare provider.

The "3.0" version of the kit — which you can no longer buy from Mars' website but is still available on Amazon — cost me $79.99 . The newest version, which you can get on their site, is $84.99. 

• Memphis Meats founder Uma Valeti sought out to find an alternative to the meat industry after discovering the brutality and unsanitary conditions behind it.
• Valeti, a doctor, teamed up with a molecular biologist, Eric Schulze, to create meat products in a petri dish.
• The startup, backed by Bill Gates and Richard Branson, has already cultivated and harvested edible beef, chicken, and duck in its bioreactors.
• Memphis Meats is working towards making its homegrown meat more affordable for mass market — and also more appetizing.

Uma Valeti remembers the first time he really thought about where meat comes from.

A cardiologist turned founder, Valeti grew up in Vijayawada, India, where his father was a veterinarian and his mother taught physics. When he was 12, he attended a neighbor's birthday party.

In the front yard, people danced and feasted on chicken tandoori and curried goat. Valeti wandered around to the back of the house, where cooks were hard at work decapitating and gutting animal after animal to keep the loaded platters coming. "It was like, birthday, death day," he says. "It didn't make sense."

Valeti remained a carnivore for more than a decade, until after he had moved to the U.S. for his medical residency. But in time, he found himself increasingly disturbed by food-borne illness. He was especially grossed out by the contamination that happens in slaughterhouses when animal feces get mixed in with meat. "I loved eating meat, but I didn't like the way it was being produced," he says. "I thought, there has to be a better way."

In a tiny R&D suite in a nondescript office building in the unglamorous Silicon Valley exurb of San Leandro, a lanky, red-haired molecular biologist named Eric Schulze is fiddling with a microscope, and I'm about to get a look at that better way. Like the specimen he'll show me, Schulze is something of a hybrid.

Formerly a Food and Drug Administration regulator, he's now an educator, TV host, and senior scientist at Memphis Meats, the company that Valeti founded in 2016 and whose laboratory he is showing me. Lining one wall is a HEPA-filtered tissue cabinet, to which someone has affixed a "Chicken Crossing" sign, and a meat freezer labeled "Angus." Along the opposite wall is an incubator dialed to 106 degrees Fahrenheit, the body temperature of Anas platyrhynchos domesticus—the domestic duck.

Schulze plucks a petri dish from the incubator, positions it under the microscope, and then invites me to look into the twin eyepieces. "Do you see those long, skinny things? Those are muscle-forming cells," he says. "These are from a duck that's off living its life somewhere." The cells look like strands of translucent spaghetti, with bright dots—nuclei, Schulze says—sprinkled here and there.

He removes that petri dish and inserts another. In it, scattered among the spaghetti strands, are shorter, fatter tubes, like gummy worms. Those, he explains, are mature muscle cells. Over the next few days, they'll join together in long chains, end to end, and become multicellular myotubes. These chains will form swirls and whorls until they look like the sky in Van Gogh's Starry Night. Also, Schulze casually notes, "they'll start spontaneously contracting."

Wait. Contracting? As in ... flexing?

"This is all living tissue. So, yes," Schulze says.

The idea of a dish full of duck mince suddenly beginning to twitch and squirm makes me shake my head. What's making duck bits move if not a brain and nerves? Schulze is used to this reaction. "For the past 12,000 years, we've assumed that when I say the word 'meat,' you think 'animal,' " he says. "Those two ideas are concatenated. We've had to decouple them."

Meat without animals. It's not a new notion. In a 1932 essay predicting sundry future trends, Winston Churchill wrote, "We shall escape the absurdity of growing a whole chicken in order to eat the breast or wing, by growing these parts separately under a suitable medium."

The basic science to grow meat in a lab has existed for more than 20 years, but no one has come close to making cultured meat anywhere near as delicious or as affordable as the real thing. But sometime in the next few years, someone will succeed in doing just that, tapping into a global market that's already worth trillions of dollars and expected to double in size in the next three decades. Despite a bevy of well-funded competitors, no one is better positioned than Memphis Meats to get there first.

Operating with a team of just 10 (though it's expected to grow to 40 in a matter of months), the startup has already cultivated and harvested edible beef, chicken, and duck in its bioreactors, a feat no one else has achieved. Even allowing for the vagaries of regulation—it's not clear which federal agency will oversee a foodstuff that's real meat but not from animals—the company expects to have a product in stores by 2021.

"They're the leader in clean meat. There's no one else that far along," says venture capitalist Steve Jurvetson, whose firm led Memphis Meats' recent $17 million Series A.

Before he met Valeti in 2016, Jurvetson spent almost five years researching lab-grown meat and meat alternatives, believing the market was set to explode. "They're the only one that convinced me they can get to a price point and a scale that would make a difference in the industry," he says.

Going in with Jurvetson was a lineup of household-name investors that includes Bill Gates, Richard Branson, and Jack Welch; their money will be used to build up Memphis Meats' already formidable trove of intellectual property and to fine-tune the process of combining cells to produce the tastiest steaks and patties, and drive down the cost. The infusion of prestige also boosts competitors. Memphis Meats' lineup of backers "is enormous, especially for a small company like mine," says Mike Selden, CEO of lab-grown fish-filet startup Finless Foods. "When investors tell me, 'Great idea, but we can't really vet the technology,' I can say, 'Richard Branson and Bill Gates think it's great.' "

The business case for clean meat, as the fledgling industry's progenitors prefer to call it, could hardly be plainer. As emerging middle classes in places like China and India adopt Western-style diets, global consumption of animal protein skyrockets. (Memphis Meats is working on duck because it's so popular in China, which consumes more of it than the rest of the world combined.) But the U.N.'s Food and Agriculture Organization estimates 90 percent of the world's fish stocks are now fully exploited or dangerously overfished. More than 25 percent of Earth's available landmass and fresh water is used for raising livestock. Only one of every 25 calories a cow ingests becomes edible beef. And meat processors often must pay disposal companies to haul away their inedible tonnage—hooves, beaks, fur, cartilage.

But it's not just the financial opportunity that has the likes of Gates and Branson so excited: Meat is an ongoing environmental and public-health catastrophe. Livestock account for 14.5 percent of greenhouse gas production—more than all transportation combined. As meat demand soars, virgin rainforest gets razed to grow feed, and freshwater sources are diverted from drought-prone regions. Overcrowded pig and poultry farms are reservoirs for global pandemics; animals raised in them are pumped full of anti­biotics, spurring the rise of drug-resistant superbugs.

A subset of affluent consumers is willing to pay higher prices for free-range beef, cage-free eggs, and other animal products marketed as sustainably produced and cruelty-free, but that's a tiny slice of the market. With the FAO expecting meat consumption to nearly double by 2050, only a radical break with the past will prevent doubling down on practices such as high-density feedlots and vertical chicken farms.

The idea of such a radical break attracted Branson, who stopped eating beef in 2014 out of concern over deforestation and slaughterhouse practices. "I believe that in 30 years or so," he wrote in a blog post, "we will no longer need to kill any animals and that all meat will either be clean or plant-based."

Big as it would be if Branson's prediction comes true, those behind Memphis Meats believe they're part of something even larger. Already, so-called cellular agriculture produces everything from leather and vaccines to perfume and building materials. Within a few years, proponents say, it could eliminate organ donation, oil drilling, and logging. The possibilities are as broad as life itself. "Human civilization was largely enabled by the domestication of livestock," says Nicholas Genovese, Valeti's co-founder. "If we can master producing meat without livestock, it's really going to be the second domestication."

Valeti's meat-without-animals epiphany came soon after his cardiology fellowship at the Mayo Clinic in 2005. In a cutting-edge clinical trial, he used stem cells to repair damage caused by cardiac arrest. Stem cells are undifferentiated cells that can become different types of tissue as they mature; injected into a heart that's been ravaged by a coronary, they can form healthy new muscle to replace what has been lost. If stem cells could be cultivated into heart muscle, he thought, why couldn't they be manipulated into making a drumstick or a porterhouse? Why not grow just the porterhouse and skip the rest of the cow? And while you're at it, why not grow a steak with a healthier nutritional profile?

A bit of research showed Valeti that he was far from the first to have the idea—but also convinced him that what hadn't been feasible was quickly becoming so. Rapid DNA sequencing was making it radically faster and cheaper to, say, program yeast cells to manufacture proteins. Advances in data science made it possible to tease out relationships in huge volumes of experimental data. Meanwhile, the growing high-end market for sustainable and humanely raised foods pointed to a path for a product that was bound to be expensive in its earliest incarnations.

"If I continued as a cardiologist, maybe I would save 2,000 or 3,000 lives over the next 30 years," Valeti says. "But if I focus on this, I have the potential to save billions of human lives and trillions of animal lives." His ambitions got a major boost in 2014, when a friend from New Harvest, a nonprofit institute that supports work in cellular agriculture, offered to introduce him to Genovese, a stem cell biologist. Like Valeti, Genovese had become vegetarian. As a high school student, Genovese was a member of his local 4-H Poultry Club, competing to raise the largest chickens. "Everyone would get their baby chicks on the same day. A few months later, there's a weigh-in, and they give out trophies," he recalls. "As a teenager, it's very exciting." It was also sobering. Those chickens, he says, "looked up to you for their feed, and looked up to you to protect them. You lock them up at night so the foxes don't get them. But at the end, you send them to their demise."

He earned degrees in cell biology and tissue engineering and eventually got a job in a lab run by Vladimir Mironov, who was investigating the use of bioprinting—3-D printing using living cells—to generate replacement organs. In 2010, Genovese accepted a three-year fellowship from People for the Ethical Treatment of Animals, the controversy-courting animal welfare nonprofit, to conduct research into cultured meat. The PETA connection also made him a target for protest from local hog farmers, who objected to his presence after he moved to the University of Missouri. After learning about Valeti's work, Genovese quickly nabbed a position in his new lab at the University of Minnesota.

By 2015, with Genovese on board, Valeti realized it was time to ditch academia. Another New Harvest contact suggested he reach out to IndieBio, the life-sciences-oriented tech accelerator. He did, and within an hour he was on the phone with its director, Ryan Bethencourt.

Bethencourt, a vegan, was well versed in the challenges and promise of cultured meat. He had previously tried to persuade Mark Post, a Dutch researcher who'd produced the first full hamburger patty out of lab-grown beef, to bring his work to IndieBio. (Post demurred but subsequently launched MosaMeat, backed by Google co-founder Sergey Brin.) "I said to Uma, this is an opportunity to become a leader in this space and transform food as we know it," Bethencourt recalls. IndieBio became the first outside investor in Valeti and Genovese's startup, initially dubbed Crevi Foods, after the Latin word for "origin." (The founders quickly realized that it was a bit too clever. "Nobody understood it," Valeti says.)

In September 2015, the two men moved to the Bay Area and started culturing cow muscle and connective tissue cells. (We think of meat as synonymous with muscle, but much of meat's flavor and mouthfeel comes from the breakdown of collagen, a component of skin, ligaments, and fascia. It's necessary to blend different types of cells to make lab meat that tastes like the real thing.)

By January, they had enough to make their first tiny meatball. "I'll never forget when we first tasted what we had harvested," says Valeti. "It just immediately brought back all the memories you get when you eat meat." It had been 20 years since Valeti had, but it nonetheless confirmed that, as far as they still had to go, they'd produced, on the most fundamental level, meat.

That helped validate the idea of trying to grow meat in the first place. All the aims of Memphis Meats and its ilk—­making food healthier, more humane, and more ecofriendly—could arguably be better served by leading consumers to plant-based alternatives. Such options are getting more sophisticated: Another Silicon Valley startup, Impossible Foods, has raised almost $300 million for a veggie burger that browns like ground beef and even "bleeds" when served rare, thanks to the presence of heme, a com­ponent of the blood molecule hemoglobin, which is also found in plants. The Impossible burger mimics the taste of a haute fast-food patty, though its consistency is not quite there—the outside caramelizes, but the interior is a tad puddingy. (Gates has put money into Impossible, as well as in its competitor, Beyond Meat.)

But the lab-grown-meat crowd believes plants will never be the whole answer. Meat is simply too complex and culturally ingrained. "Humans evolved over thousands of years eating meat," says Valeti. A high-tech veggie burger might be able to replace ground chuck, but that's one narrow application. Lab meat, he says, "because it's meat, can be cooked any way meat is cooked. People can buy it off the shelf, take it home, and cook it in the ways they've known for centuries."

Those arguments led Hampton Creek, one of the best-known and best-funded plant-based food startups, to expand into clean meat. For its first four years, Hampton Creek focused on using plant proteins to replace eggs in products like mayonnaise and cookie dough. But CEO Josh Tetrick came to appreciate consumers' attachment to what they know. "A big limiting step to plant-based meat is culture. My family wouldn't go to Walmart and buy something that says 'plant-based hamburger,' " says Tetrick, who grew up in Alabama.

Tetrick's pivot toward clean meat happened amid a conflict with the company's board of directors, which led to all five outside directors resigning. That followed a long series of company stumbles, including an attempted coup by top executives who tried to go behind Tetrick's back to the board and were promptly shown the door; accusations of a large-scale buyback program to boost sales, which drew scrutiny from the Justice Department; and the loss of one of its biggest distributors—Target.

Skeptics wonder if the company's surprise June announcement that it will have one or more cultivated-poultry products in stores by the end of 2018 was a diversionary tactic. The timeline seems optimistic. Even if the kinks can be worked out that quickly, there's no guarantee regulators will sign off in time. Still, Hampton Creek has raised more than $200 million in venture capital and has a team of 60 working on R&D, including top cell biologists from academia and industry.

In September, to punctuate an announcement that it had secured patents around its clean-meat processes, Tetrick tweeted a video of what looks like a burger sizzling in a skillet; a spokesman declined to say whether the video shows the company's first clean beef. A knowledgeable industry insider says Hampton Creek's progress and dysfunctions are real. "I think the only thing that will prevent Hampton Creek from being first to market with this is the company exploding," says the source. (Asked for a response to this statement, Hampton Creek declined to comment.)

For Memphis Meats, with its significant head start and singular focus, the path to success is straightforward. It needs to make its meats more appetizing and much cheaper. One morning this summer, Valeti assembled his full team to talk about how far they had come and how far they still had to go. A few weeks earlier, Memphis Meats had held its first-ever tasting for outsiders, inviting more than 25 people to sample fried chicken and duck à l'orange.

The event was deemed a success.

"They really nailed the texture and mouthfeel," one guest, sustainable food advocate Emily Byrd, said. But it was expensive. Growing that "poultry" cost about $9,000 per pound. At his company meeting, Valeti revealed that the most recent harvest, in May, had been considerably cheaper, with the meat costing $3,800 per pound. "I want it to keep going down by a thousand dollars a month," said Valeti. "Our goal is to get to cost parity, and then beat commercial meat."

That remains a distant goal. But theoretically, cultivating meat should have high startup costs but low operational costs: Given the right conditions, living cells divide on their own. The major factor governing costs is the nutrient-rich medium in which those cells grow. All the companies that have successfully grown meat have relied on fetal bovine serum, which is extracted from cow fetuses, as a key medium component.

But FBS is expensive, and significantly weakens claims cultivated-meat companies can make about vegan or cruelty-free products. Hampton Creek says it has grown and harvested chicken without FBS, although it has been tightlipped about its methods. Memphis Meats acknowledges it used FBS to start its cell lines but says, "We have validated a production method that does not require the use of any serum, and we are developing additional methods as we speak."

Tetrick likens the expense of medium—it's called "feed" at Memphis Meats—to the need electric-car makers have to develop better batteries. "If we figure out how to surmount that limiting step," he says, "suddenly all the economics start looking better."

Electric cars are an apt metaphor, because whenever clean meat does hit supermarkets, it will almost certainly be pricier than conventional meat. Memphis Meats and its competitors will likely spend a few years courting consumers who buy wild-caught Atlantic salmon and grassfed sirloin at Whole Foods. "They're going to have to somehow position it as something worth paying more for," says Patty Johnson, an analyst who covers the meat industry for Mintel Group.

One possibility, she says: Like Impossible Foods, Memphis Meats could persuade influential chefs to feature its wares on their menus. Another would be genetically engineering nutritional profiles so the company could tout increased health benefits—adding, say, omega-3 fatty acids to beef to make it as healthy as salmon.

Valeti is careful to avoid sounding as if he wanted to put Big Meat out of business. He argues that the big meat processors will be keen on clean technology, whether as licensees, customers, investors, or acquirers. (Agribusiness giant Cargill joined Gates and Branson in Memphis Meats' Series A; Tyson Foods has a venture fund that invests in similar technologies.) Cows and pigs aren't getting any cheaper to raise or slaughter, but if lab meat follows the course of other early-stage technologies, it can continue to get more inexpensive for years to come. "It's not crazy to think you might one day be able to brew meat at $2 per pound, $1 per pound," says Bethencourt. "At that point, we can replace pretty much all industrial meat. In 20 years, I think people will look at growing and killing an animal as bizarre."

And while Missouri's pig farmers may see their doom in a world of meat without animals, companies that buy meat from farmers view it very differently, explains Jurvetson. When an outbreak of avian flu or mad cow strikes, "if you're in their industry, it's a very scary world," he says.

Valeti won't mince words, either. "The status quo in animal agriculture is not OK. That status quo is going to kill a lot of people." All the more reason to bring on the second domestication.

SEE ALSO: A San Francisco startup just created the world's first lab-grown chicken

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• English majors are surprisingly well-represented in US medical schools.
• They enroll in med schools at greater rates than applicants coming from science backgrounds.
• And it's not necessarily the case that English is easier than biology or chemistry.

There's a decent chance your doctor didn't study biology, chemistry, or any other science when they first got to college.

A surprising number of students in medical schools actually have backgrounds in a surprising field: English.

According to career site Zippia, English is the seventh-most popular undergraduate major for doctors, and the most popular major that isn't a hard science or medical field.

Take a look at the list:

1. Biology
2. Biochemistry, Biophysics, Molecular Biology
3. Psychology
4. Chemistry
5. Nursing
6. Health/Medical Preparatory Programs
7. English
8. Biomedical Engineering
9. Economics
10. History

People who major in English and other fields in the humanities also appear to enroll in medical schools at greater rates than other majors. According to the most recent data from the Association of American Medical Colleges, 46% of humanities majors who applied to US med schools ended up enrolling, compared to just 38% of biological science majors and 44% of physical science majors.

Humanities majors also boasted the highest MCAT scores of all applicants, Zippia found. (It is worth noting that just over 1,900 humanities majors applied to med schools last school year, compared to more than 28,000 biological science majors.)

So why do English majors seem to have an edge? While some speculate that majoring in English leads to a higher GPA and a more impressive resume, that likely isn't the case.

"Consider for a moment the work ethic that an English major must possess to major in something other than a pre-requisite heavy field, and then to ace the MCAT," David Luther of Zippia wrote. "Med schools do consider your narrative, medical work experience, and leadership.

"All things equal, a candidate who demonstrates passion for med school admissions is more likely to maintain sanity through the rigors of medical college."

James Pierce, a second-year medical student at the Case Western Reserve University School of Medicine, told Business Insider that studying English has benefited him in his post-graduate career.

"English is all about studying how to communicate," said Pierce, who decided he wanted to pursue medicine three years into his undergraduate studies at the University of California-Davis. "Doctors tell people what they need to know and need to express it in a way that everyone can understand."

"A lot of doctors get stuck saying too much jargon, and I think on the other side a lot of doctors maybe say too little and don't address people's concerns, because they dismiss the details of what they're trying to describe as too complicated. I hope that having an English background will help me balance those two." 

SEE ALSO: Google and Uber alums have created a doctor's office that's like an Apple Store meets 'Westworld' — and it's expanding nationwide

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NOW WATCH: Here's why marriage and doctors are the most popular jokes

• Researchers studied the cortical neurons in the brains of cats, dogs, and other animals to determine intelligence.
• The researches believe the number of cortical neurons signifies the richness of an animal's mental state.
• Cats have significantly less cortical neurons than dogs.

They might chew your shoes, occasionally pee on the rug, or snarf down your entire dinner the minute you turn your head, but it turns out your family dog is measurably smarter than your cat.

Researchers at Vanderbilt decided to put the age old debate to the test objectively, studying the number of cortical neurons in the brains of a number of animals. The results? Canines had a significantly higher number than felines.

Dogs, it turns out, have about 530 million cortical neurons. Cats have less than half that, coming in with 250 million. (We humans have about 16 billion.)

"I believe the absolute number of neurons an animal has, especially in the cerebral cortex, determines the richness of their internal mental state and their ability to predict what is about to happen in their environment based on past experience," said Suzana Herculano-Houzel, associate professor of psychology and biological sciences at Vanderbilt, who oversaw the study with a collection of international researchers.

The paper, which will be published in the journal Frontiers in Neuroanatomy (and almost certainly maligned on Reddit, the Internet's haven for cat lovers), notes that the physical size of the brain doesn't necessarily relate to overall intelligence. For example, researchers found that the brain of a brown bear, while 10 times as large as a cat's, has roughly the same number of neurons. (Raccoons, also, are on par with cats when it comes to smarts.)

Despite the findings, don't expect this argument to go away anytime soon. Herculano-Houzel herself admits that, while the study was objective, she herself does have a bit of a bias.

"I'm 100 percent a dog person," she says, "but, with that disclaimer, our findings mean to me that dogs have the biological capability of doing much more complex and flexible things with their lives than cats can."

SEE ALSO: Here's the science behind why some people love animals and others couldn’t care less

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NOW WATCH: The fascinating way cats see the world is nothing like what you might expect

• The belief that men are biologically inclined to be more aggressive and oppressive is false.
• Men do not need to repress a instinct to be aggressive because it doesn't exist.
• They are taught from an early age to repress all emotions except for anger which leads to violent outbursts.
• Toxic masculinity upholds this repression leading to many men not knowing how to communicate clearly and to associate women with emotions they deem "inferior".

While bent over locking up my bike in Chicago a few years ago, I heard the all-too-familiar sound of a wolf whistle. I turned around to get a look at the jerks accosting some woman on the street, only to realize I was the one who was being cat-called.

A man passing by from behind had seen my long curly hair and tight jeans and mistaken me for a woman. When I turned around to face him, he was shocked and started apologizing profusely. In so many words, he was saying: "This is an unacceptable way to behave toward a man." And we both knew, if I were a woman, there would be no apology.

This is the double standard at the heart of masculinity: Men are taught to regularly say and do things to women that they would never say or do to other men, that they would never want men to say or do to them. That is not due to some timeless "male libido" driving their behavior.

It's because masculinity is founded on the myth that men alone are rights-bearing persons and women are subordinate, passive, second-class beings who either need the protection of or deserve to be subjected to men.

In a recent New York Times op-ed, however, writer Stephen Marche uses some outdated Freudian ideas about sexuality and gender and the recent explosion of allegations of sexual misconduct to argue that male sexual desire is inherently brutal and oppressive.

Thus, there's no use, as Marche puts it, in "pretending to be something else, some fiction you would prefer to be." So, feminist ideas are practically useless. The only fruitful thing men can do to respect women as equals is repress their natural urges.

In truth, the very problem with masculinity Marche describes in his op-ed is too much repression: The rules governing masculinity require men to be stoic, to repress virtually all of their emotions (except anger). This leads many men to severely underdevelop their own ability to analyze and communicate about their own feelings. Our culture, not men's nature, has enforced this emotional repression.

Indeed, every man can think of at least one experience where he was punished for failing—whether intentionally or accidentally—to obey the dictates of these masculine rules. I remember a playground game where my friends and I would re-enact scenes from Disney films.

I volunteered myself for the role of Ariel from the Little Mermaid. She was the protagonist and, it seemed to me, the best character to be. My peers bullied and teased me for this failure to obey the rules of compulsory masculinity for weeks afterward, and "Ariel" became a standard go-to insult in arguments.

This policing of masculinity is the reason why the vast majority of fist fights I've witnessed between men were preceded by trash talk in which the men called each other "little bitches" or "pussies." The worst thing a man could be accused of being is feminine, since femininity is, in contrast, just another word for weak, passive, and fit to be dominated by other men. (This kind of masculinity is not just responsible for misogyny then, but for homophobia and transphobia too.)

This is the kind of masculinity that also teaches men they don't have to ask permission to act on their sexual desires. They're supposed to take charge and have no reason to respect women's autonomy. This is what feminists mean when they say sexual harassment and assault are about power, not desire.

It's our culture, not our libidos, that shapes the way men act upon otherwise healthy, run-of-the-mill sexual desires. In itself, there is nothing inherently brutal in a man who is sexually attracted to a woman he works with—no more than there would be if a woman desires a man she works with.

But there is a difference between discreetly (or silently) deriving pleasure from someone's presence, on the one hand, and imposing one's desires on that person, especially if they're unreturned or unwanted. The difference here, as the feminist philosopher Sandra Bartky puts it, is the difference between healthy eroticism and rituals rooted in toxic ideas about masculinity.

If a man wants to act on his attraction, or sexual urges? Here, communication, the very thing modern notions of masculinity train us away from, is key. Genuine communication is a two-way street; it presupposes that both participants have an equal right to withdraw from the interaction or decline an offer. Men already understand this to some extent, because this is how men typically behave in interactions with other men.

So, relating to women as equals, as genuine peers, doesn't necessarily require repressing desire. Instead, it requires coming to terms with the fact that masculinity trains men to have great difficulty recognizing women—or, indeed, anyone that presents as feminine—as persons, as agents, as authoritative and worthy of respect, and then making an effort to see and treat them that way.

In 1945 only 24 percent of Americans thought women should be allowed to hold jobs outside the home. In that same year, 25 percent of Americans thought there were often good reasons to pay men and women different amounts for doing the same kind of work. But by 1993 that number had dropped to 13 percent—and women's workforce participation rate had doubled.

In 1987, 30 percent of Americans said they agreed that "women should return to their traditional social role of remaining in the home." In 2012, by contrast, only 18 percent said this. Thus, it's no surprise that in the past 20 years, the number of dads who stay home with children has dramatically increased and men in general are spending significantly more time parenting their children. Masculinity and femininity are changing quickly, and both men and women are the better for it.

Instead of calling for repression, we should stop punishing children and adults for failing to obey the unhealthy dictates of masculinity—men need less repression, not more. That this would make for a less violent, sexist (and transphobic) world is reason enough to see it as a worthy goal. But, so, too would it free men from a great deal of anxiety, self-hatred, pain, and loneliness.

A few years before my own experience with a catcall, I saw a young woman walking down a Chicago street with a milkshake in hand. A man watching her pass by shouted, "Titties!" at her. Without skipping a beat, she turned around, threw her milkshake at him, and continued on her way. Those of us on the street chuckled in admiration as the man stood dripping from head to toe with chocolate milkshake.

Was this a man overcome by brutal sexual desires he needed to better repress? I don't think so. This was a man who needed a wake-up call that the woman he was shouting at was a person, not an object for him to dominate. Maybe the #MeToo moment will be just that for a lot of men, and we should consider ourselves lucky not to get our wake-up call served up so icy cold.

SEE ALSO: How companies can learn to better root out sexual harassment

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• Many people believe that drinking different types of alcoholic drinks affects your mood in different ways.
• This is a myth because all alcoholic drinks have the same ingredient, ethanol which depresses the nervous system.
• Researches believe attributing a certain drink to a certain mood is self-fulfilling prophecy.
• The drink's effects are mostly due to how much you've consumed in a certain amount of time.

Reports of a study linking different kinds of alcoholic drinks with different mood states were making the rounds recently. The research used 30,000 survey responses from the Global Drug Survey and found that people attached different emotions to different alcoholic drinks.

For instance, more respondents reported feeling aggressive when drinking spirits than when drinking wine.

We all have friends who swear they feel differently when drinking different types of alcohol. But can different drinks really influence your mood in different ways?

Alcohol is alcohol

Let's cut to the chase. No matter what the drink, the active ingredient is the same: ethanol.

When you have a drink, ethanol enters the bloodstream through the stomach and small intestine and is then processed in the liver. The liver can process only a limited amount of alcohol at a time so any excess remains in the blood and travels to other organs, including your brain where mood is regulated.

The direct effects of alcohol are the same whether you drink wine, beer or spirits. There's no evidence that different types of alcohol cause different mood states. People aren't even very good at recognizing their mood states when they have been drinking.

So where does the myth come from?

Grape expectations

Scientists have studied specific alcohol-related beliefs called "expectancies." If you believe a particular type of drink makes you angry, sad or sexed up, then it is more likely to.

We develop expectancies from a number of sources, including our own and others' experiences. If wine makes you relaxed, it's probably because you usually sip it slowly in a calm and relaxed atmosphere. If tequila makes you crazy, maybe it's because you usually drink it in shots, which is bound to be on a wild night out.

Or if you regularly saw your parents sitting around on a Sunday afternoon with their friends and a few beers, you might expect beer to make you more sociable. Kids as young as six have been found to have expectancies about alcohol, well before any experience of drinking.

We build conscious and unconscious associations between alcohol and our emotions every time we drink or see someone else drinking.

We could even be influenced by music and art. "Tequila makes me crazy" is a common belief, which also happens to be a line in a Kenny Chesney song, and Billy Joel's Piano Man might reinforce the idea that gin makes you melancholy.

It's the 'how' more than the 'what'

Other chemicals, called congeners, can be produced in the process of making alcohol. Different drinks produce different congeners. Some argue these could have different effects on mood, but the only real effect of these chemicals is on the taste and smell of a beverage. They can also contribute to a cracker of a hangover.

But there is no evidence that these congeners produce specific mood or behavioral effects while you are drinking.

The critical factor in the physical and psychological effects you experience when drinking really comes down to how you drink rather than what you drink. Different drinks have different alcohol content and the more alcohol you ingest – and the faster you ingest it – the stronger the effects.

Spirits have a higher concentration of alcohol (40%) than beer (5%) or wine (12%) and are often downed quickly, either in shots or with a sweet mixer. This rapidly increases blood alcohol concentration, and therefore alcohol's effects, including changes in mood.

The same goes for mixing drinks. You might have heard the saying "Beer before liquor, never been sicker; liquor before beer, you're in the clear", but again it's the amount of alcohol that might get you into trouble rather than mixing different types.

Mixing a stimulant (like an energy drink) with alcohol can also mask how intoxicated you feel, allowing you to drink more.

You can reduce the risk of extreme mood changes by drinking slowly, eating food before and while you drink, and spacing alcoholic drinks with water, juice or soft drink. Stick to drinking within the Australian alcohol guidelines of no more than four standard drinks on a single occasion.

Party animals and bad eggs

Alcohol is a central nervous system depressant, which means it slows the brain's functioning. Alcohol's effects include reducing activity in the part of the brain that regulates thinking, reasoning and decision-making, known as the prefrontal cortex. Alcohol also decreases inhibitions and our ability to regulate emotions.

"In vino veritas" (in wine there is truth) is a saying that suggests that when drinking we are more likely to reveal our true selves. While that's not completely accurate, the changes in mood when someone is drinking often reflect underlying personal styles that become less regulated with alcohol on board.

Studies of aggression and alcohol, for example, show that people who are normally irritable, cranky or low in empathy when they are not drinking are more likely to be aggressive when their inhibitions are lowered while drinking.

As with all drugs, the effect alcohol has on your mood is a combination of the alcohol itself, where you are drinking it and how you're feeling at the time.

So does alcohol make you crazy, mean or sad? If it does, you were probably a bit that way inclined already, and if you believe it enough it may just come true.

SEE ALSO: This is what alcohol really does to your body

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NOW WATCH: How much money you need to save each day to become a millionaire by age 65

The animal kingdom is home to one remarkable fact after another.

To name a few: Sperm whales can hold their breath for an hour, the most venomous animal on Earth is a snail, and tiny freshwater hydras can live so long they may as well be immortal.

But for each surprisingly true assertion about animals, there's invariably another that's exaggerated, misguided, or just plain wrong.

Here are a handful of the most popular myths about animals and the truth behind them — or the closest thing we have to it.

Have any favorites we missed? Send them to science@businessinsider.com.

Jennifer Welsh, Sarah Kramer, and Sean Kane contributed to this post.

SEE ALSO: 49 'facts' about health we often believe that are misleading, inaccurate, or totally false

DON'T MISS: 17 'facts' about space and Earth that you thought were true — but have been debunked by science

MYTH: Beaver butt secretions are in your vanilla ice cream and other foods.

You've probably heard that a secretion called castoreum, isolated from the anal gland of a beaver, is used in flavorings and perfumes.

But castoreum is so expensive, at up to $70 per pound of anal gland (the cost to humanely milk castoreum from a beaver is likely even higher), that it's unlikely to show up in anything you eat.

In 2011, the Vegetarian Resource Group wrote to five major companies that produce vanilla flavoring and asked if they use castoreum. The answer: According to the Federal Code of Regulations, they can't. (The FDA highly regulates what goes into vanilla flavoring and extracts.)

It's equally unlikely you'll find castoreum in mass-marketed goods, either.

Sources: Business Insider, Vegetarian Resource Group, FDA, NY Trappers Forum

MYTH: Dogs and cats are colorblind.

Dogs and cats have much better color vision than we thought.

Both dogs and cats can see in blue and green, and they also have more rods — the light-sensing cells in the eye — than humans do, so they can see better in low-light situations.

This myth probably comes about because each animal sees colors differently than humans.

Reds and pinks may appear more green to cats, while purple may look like another shade of blue. Dogs, meanwhile, have fewer cones — the color-sensing cells in the eye — so scientists estimated that their color vision is only about 1/7th as vibrant as ours.

Sources: Today I Found Out, Business Insider

MYTH: Humans evolved from chimpanzees.

Chimps and humans share uncanny similarities, not the least of which is our DNA — about 98.8% is identical.

However, evolution works as incremental genetic changes add up through many generations. Chimps and humans did share a common ancestor between 6 and 8 million years ago but a lot has changed since then.

Modern chimps evolved into a separate (though close) branch of the ape family tree.

Sources: Smithsonian National Museum of Natural History, American Museum of Natural History

Scientists finally have an up-close look at the deepest-dwelling fish in the world. Several samples of the fish have been brought to the surface for study. Following is the transcript of the video.

Scientists finally have an up-close look at the deepest-dwelling fish. The fish was found nearly 5 miles underwater. It's the first time scientists have retrieved one for study. This CT scan shows the fish's skeleton and its lunch.

Researchers have named the fish the "Mariana Snailfish" AKA "Pseudoliparis swirei." It was found 26,200 feet below the surface, in the Mariana Trench. The pressure is 1,000X greater than at the surface. Researchers say the pressure there is so intense, it's "similar to an elephant standing on your thumb."

In August, Japanese researchers saw the same fish even deeper, at a depth of 26,830 feet. Scientists didn't know for sure if such life could exist at this depth. It's thought that after 26,902 feet, cells cease to function normally.

Scientists caught this fish with a camera-enabled trap. They hope the samples will help them understand how something could survive such incredible pressure. One advantage to their depth is a lack of natural predators, except for the occasional scientist with a trap!

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• South African researchers have put together the most complete skeleton of a human ancestor older than 1.5 million years.
• The Australopithecus is estimated to be 3.6 million years old.
• It took the researchers 20 years to excavate and reconstruct the skeleton, which was found in a cave outside of Johannesburg.

JOHANNESBURG (AP) — Researchers in South Africa have unveiled what they call "by far the most complete skeleton of a human ancestor older than 1.5 million years ever found."

The University of the Witwatersrand displayed the virtually complete Australopithecus fossil on Wednesday.

The skeleton dates back 3.6 million years. Its discovery is expected to help researchers better understand the human ancestor's appearance and movement.

The researchers say it has taken 20 years to excavate, clean, reconstruct and analyze the fragile skeleton.

The bones were discovered in the Sterkfontein caves outside Johannesburg after foot and leg bone fragments were found from rock blasted from the cave by miners.

The researchers hail the skeleton project as important for South Africa's heritage and "our common humanity."

SEE ALSO: These recently discovered fossilized teeth could rewrite human history

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• A dinosaur newly discovered in Mongolia was most likely semiaquatic, a trait that hadn't been found in dinosaurs before.
• The finding helps establish a new subfamily of dinosaurs.
• The creature had a neck like a goose's, wings similar to those of penguins, and sharp claws like those of velociraptors.

Birds are the modern incarnation of dinosaurs.

But some birds live in ways we haven't observed in the dinosaur kingdom. Ducks, for example, alternate between water and land habitats, able to take advantage of both.

Until now, that hadn't been seen in dinosaurs, but the discovery of a duck-like dinosaur from Mongolia may change that.

The new dinosaur, Halszkaraptor escuilliei, was announced on Wednesday in the journal Nature. The remarkably complete fossil skeleton that paleontologists analyzed indicates it was likely a semiaquatic dinosaur, able to both swim and move about on land.

"This is the first dinosaur with a lifestyle similar to aquatic birds — this indicates that these dinosaurs were able to exploit an environment that was not considered in our previous interpretation of dinosaur history," Andrea Cau, a paleontologist at the Giovanni Capellini Geological Museum of the University of Bologna, said in an email.

This finding helps establish a new subfamily of similar dinosaurs, according to the paper. Several other fossil specimens from the same region fit into this family, indicating they're part of the same small branch on the evolutionary tree.

The discovery "illustrates how much of the diversity of Dinosauria remains undiscovered, even in intensely studied regions such as Mongolia," the authors wrote.

Researchers used a scanning method that Cau, the lead author of the study, described as "the most advanced scanning technology ever done on a fossil" to collect about 6,000 GB of data on the fossil while it was still partially embedded in rock. The dinosaur lived between 71 million and 75 million years ago.

It's hard to prove that this was, in fact, a semiaquatic creature, but the specimen has several features that match those of semiaquatic and fully aquatic reptiles and birds. Its arms had structures similar to those that birds like penguins use to swim. And it had a neck like a goose's, with rows of teeth in its mouth.

But instead of webbed feet, it had claws and toes like those of theropod family, which includes velociraptors and Tyrannosaurus rex.

The dinosaur most likely fed on fish, crustaceans, and small reptiles and mammals, Cau said. The other members of this subfamily would have been a similar size.

The finding shows that there's still plenty of new history to be revealed as paleontologists scour the Earth for remains of the past.

SEE ALSO: These are 15 of the best photos scientists took in 2017 — and they show the world in stunning ways

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NOW WATCH: Scientists uncovered a bloody, feathered dinosaur tail that got stuck in tree sap 99 million years ago

• Years after Charles Darwin published "On the Origin of Species," he responded to a reader who wanted the biologist to explain whether his theory destroys the argument for an all-creating God.
• Darwin wrote a three-page letter, citing his own ailing health as one of the reasons he couldn't definitively answer the question. 
• The letter was auctioned off at Sotheby's on December 12 for $125,000 to a private American collector, the auction house said. The winning bid was more than double the estimated $40,000-$60,000 the letter was expected to fetch. 

When Darwin published "On the Origin of Species by Means of Natural Selection" in 1859, many people saw the book as an attack on religion. How could the world have been created in seven days if the evolution of living creatures on Earth took place over hundreds of thousands of years, as Darwin claimed? 

A curious young reader named James Grant wanted to know more about how Darwin thought his theory might change the idea that an omnipotent God was the ultimate creator of all beings.

Grant wrote to Darwin in March 1878, asking the biologist to “in two or three words” explain whether his theory "destroys the evidence of the existence of a God looked at through nature’s phenomena."

Darwin, who was 69 at the time, responded just five days later with a "private" note a bit longer than the reply Grant had requested. In his three-page letter, which was auctioned off for $125,000 at Sotheby's in New York on Tuesday, Darwin refused to definitively pit science against religion. 

Instead of providing a yes-or-no answer, Darwin lobbed the question back to his reader, calling it an “insoluble” problem without a simple, universal answer.

The strongest argument for God, Darwin said, is found in the instincts and intuitions of people, who might “feel that there must have been an intelligent beginner of the Universe.”

Darwin was just four years from his death when he wrote the letter, and was clearly not so sure about his own stance on God, writing that there is inevitably a "doubt and difficulty whether such intuitions are trustworthy."

The scientist's final line to Grant urges the boy not to be afraid of the latest science, regardless of how he feels about God. Darwin wrote that that while he couldn't answer the question of religion, "no man who does his duty has anything to fear, and may hope for whatever he earnestly desires."

Here’s the full text of Darwin’s letter: 

March 11, 1878. 

Private.

Dear Sir, 

I should have been very glad to have aided you in any degree if it had been in my power. But to answer your question would require an essay, and for this I have not strength, being much out of health. Nor, indeed, could I have answered it distinctly and satisfactorily with any amount of strength. 

The strongest argument for the existence of God, as it seems to me, is the instinct or intuition which we all (as I suppose) feel that there must have been an intelligent beginner of the Universe; but then comes the doubt and difficulty whether such intuitions are trustworthy.

I have touched on one point of difficulty in the two last pages of my “Variation of Animals and Plants under Domestication,” but I am forced to leave the problem insoluble.No man who does his duty has anything to fear, and may hope for whatever he earnestly desires.

Dear Sir,

yours faithfully,

Ch. Darwin.

SEE ALSO: 7 strange and surprising ways that humans have recently evolved

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NOW WATCH: Evolutionary biologists have been misinterpreting a key point in Darwin’s theory for years

• A new study of a fossil from Burma reveals a tick grasping a dinosaur feather, providing our first evidence that ticks preyed on dinosaurs.
• Scientists also found a new species of tick — Deinocroton draculi, or "Dracula's terrible tick"— that fed on dinosaur blood.
• Unfortunately, the "Jurassic Park"-style extraction of dinosaur DNA from the ticks is still impossible.

Mosquitoes weren't the only creatures to feed off the blood of dinosaurs and then to get trapped in amber.

Blood-sucking ticks also feasted off dinosaurs 99 million years ago, according to a new study published in the journal Nature Communications that examines a Burmese amber fossil containing a trapped tick grasping a dinosaur feather.

It's the first direct evidence we have of the parasites feeding on dinosaurs, according to the study. It's also the oldest evidence of ticks acting as parasites, feeding on other creatures.

"Ticks are infamous blood-sucking, parasitic organisms, having a tremendous impact on the health of humans, livestock, pets, and even wildlife, but until now clear evidence of their role in deep time has been lacking," Enrique Peñalver, lead author of the study, said in a press release.

Inside other chunks of Burmese amber, the researchers found the remains of new tick species that they believe fed off of dinosaurs, as two appeared they had been feeding from a nest of feathered dinosaurs. The new tick species is named Deinocroton draculi, or "Dracula's terrible tick"— one particularly bloated specimen was so swollen with blood that it was eight times the size of its non-engorged companions.

Unfortunately (or fortunately, depending on your perspective), the Jurassic Park scenario where DNA is extracted from an ancient blood-sucker trapped in amber is no more possible with these ticks than it would be with mosquitoes.

DNA molecules themselves degrade far too quickly for remains to still contain a legible genetic code (some researchers think our best chance of re-creating dinosaurs is to reverse engineer them using genetic editing tools).

The blood inside the tick that died shortly after feasting on what was presumably a mid-Cretaceous — something like a velociraptor — had been damaged enough by other minerals that it was impossible to identify whatever had made up its last meal.

But we now know that extinct species of the same sorts of parasites that cause us all kinds of problems today were up to the same thing back then. And whatever caused the final extinction of the dinosaurs, we know that ticks managed to thrive through the event.

SEE ALSO: The asteroid that wiped out the dinosaurs might not have killed them all if it had hit somewhere else

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NOW WATCH: A nutritionist reveals 3 foods that boost your energy levels

• Silicon Valley venture firm Andreessen Horowitz is launching a second fund that will focus on biology, investing $450 million. 
• This one, building on the experience a16z has had with its first biofund, which launched in 2015 with $200 million, will focus on the intersection of biology and engineering. 
• The fund will focus on investing in companies applying engineering to things like drug discovery, creating new uses for biology, and finding new ways for software to "eat" healthcare. 

The venture capital firm with a tagline that "software is eating the world" thinks the same could happen with biology.

On Thursday, Andreessen Horowitz launched its second bio-focused fund to invest $450 million in companies that sit at the intersection of biology and engineering. 

It's the second bio-fund Andreessen Horowitz has done. In 2015, it launched a fund with $200 million to invest in companies that were focused on biology and computer science. 

Andreessen Horowitz general partner Jorge Conde, who will be leading the fund with Vijay Pande, said that the second fund's approach to focus on engineering more broadly happened because the firm saw opportunities that extended beyond just computer science. 

"We're at the precipice of bio becoming a part and a transformative part of not just healthcare, but across many industries," Conde told Business Insider. "Whether it's energy or food or consumer products, that to us is an extraordinarily exciting moment and area for us to pursue."

The fund will focus in on three areas where engineering and biology are coming together. 

• Computational biomedicine, and how machine learning and artificial intelligence can apply to biology.  It's an area a16z's already invested in with companies like Freenome, a company developing a test to look for signs of cancer in the body, and twoXAR, a company using machine learning to help with drug discovery. 
• New ways to use biology, either by reading genetic information, writing it out to make changes to organisms, or by programming organisms to take on a task. These new uses could be things like gene editing, building synthetic DNA, or reprogramming cells to fight certain diseases like the cell therapies being used in cancer.
• Finding companies building software that "eats" healthcare, especially by creating network effects.

SEE ALSO: Why an investor at Andreessen Horowitz thinks software is the future of healthcare

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Contrary to popular belief, fin collapse doesn't just affect captive whales. Biologists think there are several reasons for the phenomenon. Following is a transcript of the video.

Contrary to popular belief, it's not just in captive whales. The phenomenon is more common in captivity, but people have also seen wild orcas with curved fins. So, the cause cannot be captivity alone.

Ultimately, what's going on is the collagen in the dorsal fin is breaking down. One reason this may happen is from temperature. Warmer temperatures can disrupt collagen's structure and rigidity. Which may explain why more captive whales have curved fins.

In captivity, whales breach the surface more often, exposing their fins to the warmer air. It doesn't take long for this process to happen. One group developed curved fins after a month in captivity. But once the group was released back to the wild the fins reverted to normal.

While temperature is a leading theory, some experts think speed could also be a factor. In the wild, killer whales swim on average 3 to 4 mph and can sprint at speeds up to 34 mph. At those speeds, water creates a considerable force against the fin, which could keep the fin strong and upright. Captive whales don't have enough space to reach these speeds. Ultimately, the curved dorsal fin is still a mystery. Curved, or not, the orca's giant fin is a beacon to all, this apex predator is a force to reckon with.

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• A new analysis of the oldest known microbial fossils revealed that several diverse types of organisms existed more than 3.4 billion years ago.
• The finding indicates that life first evolved on Earth long before that.
• If life existed in so many forms that early in Earth's history, it suggests a higher likelihood that life has evolved elsewhere, too.
• "If the conditions are right, it looks like life in the universe should be widespread," said one of the authors who led the study.

The mysterious story of how life on Earth began just became a bit clearer, thanks to a new analysis of the oldest known fossil microorganisms.

Findings from that analysis indicate that diverse life existed on our planet far before many scientists thought it was possible. That means it might have been easier for life to evolve than they realized, which would increase the likelihood that life is widespread throughout the universe.

For this new discovery, scientists conducted a detailed study of a group of mysterious fossils that were discovered in Australia in 1992. These fossils are microscopic squiggles in ancient rock that's more than 3.4 billion years old.

"The rocks we studied are about as far back as rocks go," J. William Schopf, a professor of paleobiology at UCLA and lead author of the study announcing the findings, said in a press release.

'It was not difficult for primitive life to form'

Using a cutting-edge tool known as secondary ion mass spectroscopy, or SIMS, Schopf and his colleagues analyzed the carbon signatures of the microscopic squiggles. (Different forms of life have different carbon signatures.)

In one sample of rock, that analysis led researchers to identify at least three different kinds of microorganisms.

"[The analysis] tells us life had to have begun substantially earlier and it confirms that it was not difficult for primitive life to form and to evolve into more advanced microorganisms," Schopf said.

Although some scientists had been reluctant to say that life existed so early in Earth's timeline, this analysis suggests that the squiggles were indeed biological creatures and not some sort of mineral deposit, the authors wrote in the study.

Mineral deposits would likely have all had an identical signature, according to John Valley, a professor of geoscience at the University of Wisconsin–Madison who teamed up with Schopf to lead the study.

"I think it's settled," Valley said in a press release.

Big implications for a new discovery

The carbon signature of one type of microorganism in the rock indicates that it was some kind of primitive bacteria that produced carbon using light. That process was an early sort of photosynthesis that didn't rely on oxygen, since there there was little oxygen on Earth at the time.

Another type of microorganism seems to have consumed methane, which was a major part of Earth's atmosphere at the time. And the third identifiable signature belonged to a microorganism that fits into a category known as Archaea — that one would have produced methane.

Schopf said there is other evidence that suggests there were organisms that used sulfur more than 3.4 billion years ago as well.

Together, this information indicates that life had significant time to evolve and take different forms before these fossils were created.

"By 3.465 billion years ago, life was already diverse on Earth; that's clear — primitive photosynthesizers, methane producers, methane users," Schopf said.

Life could go back 4 billion years or even to the first liquid oceans 4.3 billion years ago, though it's hard to know for sure.

This still leaves big questions about life's origin. There are other, more controversial fossils that may be even older. And one of the biggest debates researchers have is about whether life first originated at volcanic hydrothermal vents in the ocean or whether life first fused in warm little pools, where meteorites could have delivered the precursors to life.

We still don't know which of those options is more plausible. But the fact that life seems to have appeared and diversified so long ago suggests it's more likely the same process could occur on other planets.

Schopf, Valley, and their colleagues aren't just interested in the origin of life on Earth, as compelling as that question is. This research was funded by the NASA Astrobiology Institute, which studies how life originated on Earth and could have originated elsewhere, too. These same techniques will likely be used to study Mars samples to look for signs of life.

"[I]f the conditions are right, it looks like life in the universe should be widespread," Schopf said.

SEE ALSO: There’s new evidence that life on Earth began with meteorites crashing into warm little ponds

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NOW WATCH: A dermatologist explains the mistakes everyone makes after working out

• We don't all have good excuses to get out of exercising.
• But some people are actually "allergic" to working out.
• It is called "exercise-induced anaphylaxis," and affects about 2% of people.
• Doctors think having an intolerance to certain foods combined with physical exertion causes an allergic reaction.

Sometimes when I exercise, I get hives on my arms or the back of my legs. It's a bit like when I go near a horse and get an allergic reaction, but without the itchiness and inability to breathe.

This puts me on the lower end of the spectrum of having "exercise-induced anaphylaxis," or EIA. It's basically an allergy to exercise, and it affects about 2% of the population.

It most often happens after vigorous physical activity like jogging, tennis, dancing, and bicycling. But lower levels of exercise such as walking can also cause a reaction.

My EIA isn't severe enough to make me stop running, but for other people it can be. In some rare cases, it can even be deadly.

It's quite similar to other allergies, which differ in severity from person to person. During an allergic reaction, your immune system makes antibodies — proteins in the blood that fight bacteria and foreign bodies. When someone with EIA exercises, antibodies are produced to fight against something, even though they aren't needed.

Antibodies release several different immune system chemicals, such as histamine, which cause allergy symptoms like a runny nose and inflamed skin.

EIA symptoms include hives, flushing, wheezing, and sometimes digestion problems. If you keep exercising when it occurs, your reaction could get more severe, such as throat closing, or low blood pressure, which can lead to circulatory failure.

That all sounds pretty scary. And it's the main reason I still take my inhaler to the gym, even though I haven't really needed it for several years.

It might be caused by your diet

Doctors don't always know what causes it.

In many cases, people experience a subset of EIA called food-dependent exercise-induced anaphylaxis (FDEIA). This is when you exercise soon after eating a specific food, and it causes a reaction.

You might not usually have any allergic symptoms when you eat the food normally, but something about the combination of physical exertion and the food sets off your immune system.

According to Medscape, the most common foods linked to FDEIA are wheat, shellfish, tomatoes, peanuts, and corn. But other foods have been reported to have an impact too, like meat, fruit, seeds, milk, soy, lettuce, peas, beans, and rice.

It might not be as simple as avoiding these foods, though, as there is also a nonspecific form of FDEIA, where eating any food before exercise can kick off a reaction.

There's also a chance it is something you're breathing in, such as dust mite debris, or mould spores.

It probably won't go away

Unfortunately, the only way to prevent EIA is by exercising at a lower intensity. Or, you can change the type of exercise you do, as swimming hasn't been associated with EIA.

If you suspect food is inducing the reaction, the medical recommendation is to stop eating six to eight hours before exercising. Very hot or cold weather can also worsen the reaction, so avoid working out during those times.

Depending on the severity of your reaction, it might also be a good idea to see a doctor and get an Epipen, which is filled with emergency injectable adrenaline (epinephrine) that stops the reaction.

SEE ALSO: If your music appears to slow down when you exercise, this is what could be happening in your brain

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