Michael Smeltzer and Deborah Brewington, Vanderbilt University
Michael Smeltzer and Deborah Brewington, Vanderbilt University

Having Neanderthal DNA May Increase Your Risk of Certain Diseases

Michael Smeltzer and Deborah Brewington, Vanderbilt University
Michael Smeltzer and Deborah Brewington, Vanderbilt University

How far back do you know your family’s medical history? All the way back to your grandparents? Your great-grandparents? Scientists are looking much farther back, at prehistoric peoples. And one research team has a pretty mind-blowing theory about an influential factor on some modern people’s genes: Neanderthal DNA. The researchers presented their findings today in Washington, D.C. at the annual meeting of the American Association for the Advancement of Science, and have also published a report in the journal Science.

Recent advances in biotechnology have given scientists access to the genetic material of Neanderthals and other pre-modern Homo species. Comparison of their DNA with that of modern humans revealed that around 50,000 years ago, early Eurasian humans and the Neanderthals were … fraternizing. As a result, modern humans with Eurasian ancestry possess about 2 percent Neanderthal DNA. Just what that percentage is and how it relates to the rest of your genes varies from person to person.

Researchers wondered how being part Neanderthal might affect modern humans. They suspected that interbreeding with Homo neanderthalensis must have given early humans some sort of genetic advantage.

“Neanderthals had been living in central Asia and Europe for hundreds of thousands of years before our ancestors ever arrived in these regions,” co-author Tony Capra said at the meeting this morning. “Thus, they had likely adapted to the distinct environmental aspects compared to Africa, such as the climate, plants and animals, and pathogens.”

Those helpful adaptations, Capra continued, would have been passed along to any human newcomers born of Neanderthal-human unions. This human/Neanderthal admixture, as scientists call it, may have made those humans more likely to survive.

“Perhaps spending a night or two with a Neanderthal was a relatively small price to pay for getting thousands of years of adaptations,” Capra said.

To test this hypothesis, the researchers analyzed genetic data from both Neanderthals and modern humans. They compared more than 28,000 anonymous patient health records with known Neanderthal genetic variations.

What they discovered was surprising. The scientists did find evidence that Neanderthal genes may have benefited early humans. But those genes may have outlasted their welcome. The results showed that Neanderthal genes can actually be detrimental to modern humans of Eurasian descent, potentially raising their risk for 12 different medical conditions, including depression, nicotine addiction, and heart attacks

But that revelation comes with a lot of caveats. For starters, the risks, like the genes that present them, vary from person to person. Clearly not all humans with Eurasian ancestry are at high risk for all 12 diseases. Second, the influence of the Neanderthal DNA on risk is both variable and minimal. Having Neanderthal forebears “by no means dooms us to have these diseases,” Capra noted at the meeting.

These results also do not mean that Neanderthals or early humans had these diseases, Capra continued. “Just because the DNA causes problems in our modern environment doesn’t mean it was detrimental in a very different environment 50,000 years ago.” Look at nicotine addiction, for example. Prehistoric people didn’t even use tobacco.

“What our results are saying,” Capra elaborated, “is not that the Neanderthals were depressed, or that they’re making us depressed. It’s that we find that the bits of DNA we inherited from Neanderthals are having an influence on these [body] systems. What that effect is remains to be seen.”

It’s also important to note that these results were derived from patient data—that is, people who were already having medical issues of one kind or another. Speaking at the meeting, co-author Corinne Simonti noted that it’s also possible that Neanderthal DNA is still helpful in some way. “Just because [it] negatively affects risk for disease doesn’t mean it’s not protective for other things,” she said.

“Ultimately,” said Capra, “we hope that our work leads to a better understanding of how humans evolved, and how our recent evolutionary history influences how we get sick.”

Courtesy of October Films
This Scientist's Idea of the 'Perfect' Human Body Is Kind of Terrifying
Courtesy of October Films
Courtesy of October Films

The perfect human body has the legs of an ostrich, the heart of a dog, and the eyes of an octopus, according to anatomist Alice Roberts. And it’s utterly terrifying.

With the help of anatomical artist Scott Eaton and special effects designer Sangeet Prabhaker, Roberts created a life-size replica of herself that fixes many design flaws inherent to the human body, Motherboard reports. Roberts unveiled the sculpture on April 23 at the Science Museum in London. On June 13, the BBC released a documentary about the project.

Among the flaws Roberts’s sculpture corrects are humans’ inferior ears, spine, and lungs. Roberts borrowed anatomy from reptiles, birds, and other mammals to create a Frankenstein-esque creature straight from the island of Dr. Moreau.

The sculpture of Alice 2.0, left, with Alice Roberts, right
Courtesy of October Films

The sculpture has legs like an ostrich because, as Roberts says on her website, the human knee is complex and prone to failure. Like humans, ostriches are bipedal, but they are far better runners. Bird-like lungs that keep air flowing in one direction, not two, make running and other aerobic activities easier for the perfect human to manage. And a chimpanzee’s sturdier spine and a dog’s heart (which has more connected arteries, leading to lower heart attack risk) make Roberts’s alternate self more resistant to injury and disease.

Roberts’s ideal human body also has skin like a frog that can change shades based on the environment, and large, bat-like ears that amplify sound. Roberts also fixed humans’ backwards retina, which produces a natural blind spot, by borrowing from octopus eye anatomy.

Perhaps most disturbing of all is the baby head poking out of the sculpture’s marsupial pouch. Roberts says marsupial pregnancy would be far easier on the human body and more convenient for parents on the go.

“This could be a human fit for the future,” Roberts says at the end of a trailer for her BBC documentary.

[h/t Motherboard]

Scientists Accidentally Make Plastic-Eating Bacteria Even More Efficient

In 2016, Japanese researchers discovered a type of bacteria that eats non-biodegradable plastic. The organism, named Ideonella sakaiensis, can break down a thumbnail-sized flake of polyethylene terephthalate (PET), the type of plastic used for beverage bottles, in just six weeks. Now, The Guardian reports that an international team of scientists has engineered a mutant version of the plastic-munching bacteria that's 20 percent more efficient.

Researchers from the U.S. Department of Energy's National Renewable Energy Laboratory and the University of Portsmouth in the UK didn't originally set out to produce a super-powered version of the bacteria. Rather, they just wanted a better understanding of how it evolved. PET started appearing in landfills only within the last 80 years, which means that I. sakaiensis must have evolved very recently.

The microbe uses an enzyme called PETase to break down the plastic it consumes. The structure of the enzyme is similar to the one used by some bacteria to digest cutin, a natural protective coating that grows on plants. As the scientists write in their study published in the journal Proceedings of the National Academy of Sciences, they hoped to get a clearer picture of how the new mechanism evolved by tweaking the enzyme in the lab.

What they got instead was a mutant enzyme that degrades plastic even faster than the naturally occurring one. The improvement isn't especially dramatic—the enzyme still takes a few days to start the digestion process—but it shows that I. sakaiensis holds even more potential than previously expected.

"What we've learned is that PETase is not yet fully optimized to degrade PET—and now that we've shown this, it's time to apply the tools of protein engineering and evolution to continue to improve it," study coauthor Gregg Beckham said in a press statement.

The planet's plastic problem is only growing worse. According to a study published in 2017, humans have produced a total of 9 billion tons of plastic in less than a century. Of that number, only 9 percent of it is recycled, 12 percent is incinerated, and 79 percent is sent to landfills. By 2050, scientists predict that we'll have created 13 billion tons of plastic waste.

When left alone, PET takes centuries to break down, but the plastic-eating microbes could be the key to ridding it from the environment in a quick and safe way. The researchers believe that PETase could be turned into super-fast enzymes that thrives in extreme temperatures where plastic softens and become easier to break down. They've already filed a patent for the first mutant version of the enzyme.

[h/t The Guardian]


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