Scientists Devise Clever Way to Test Old Manuscripts’ DNA

Jim Forest, Flickr Creative Commons // CC BY-NC-ND 2.0
Jim Forest, Flickr Creative Commons // CC BY-NC-ND 2.0

When encountering an obstacle, some people stop and give up, some force their way through, and others find another way around. That's what scientists in the United Kingdom have done with a delicate manuscript from the Dark Ages. Barred from taking parchment samples, the resourceful researchers instead analyzed the eraser crumbs left behind after archivists cleaned the paper. They describe their findings in an article on the prepress server bioRxiv.

Co-author and archaeologist Matthew Collins of the University of York did not start out a manuscript man. Collins had been trying to extract DNA from animal bones unearthed at a Viking settlement to learn more about the culture's use of livestock. But the bones had decayed too far to offer much in the way of genetic material. "You can imagine the frustration," Collins said in an interview with The Atlantic.

Then he realized that animal remains can be more than just bones. There are skins, too—and those, at least, we've taken some pains to preserve. At least the ones we've written on.

"You look at [archive] shelves," Collins said, "and every one of them has a skin of an animal with a date written on it."

Collins's excitement at discovering this untapped bounty of data was soon tempered when he and his collaborator, biochemist Sarah Fiddyment, learned that sampling the manuscripts was completely off-limits.

But they weren't about to give up that easily. Fiddyment spent weeks following the conservators as they worked with the fragile animal-skin paper, learning their process and watching for possible openings. Finally, she saw it: eraser crumbs.

Conservators routinely use PVC erasers to lift stains, grime, and damage from historic documents. The friction created by gently rubbing the eraser against the paper creates an electric charge that pulls in molecules of dirt and oil. And probably other things, too, Fiddyment thought.

Fiddyment, Collins, and their colleagues began collecting eraser crumbs from manuscript conservators around the world. They analyzed each document's chemical makeup and were even able to compare proteins to identify the livestock species responsible for the skin.

The next step was to look at the DNA itself. The researchers turned to the York Gospels, a leatherbound Bible with pages dating back to the year 990. By collecting another tiny pile of eraser crumbs from cleanup of eight pages, they were able to collect enough of a sample to run thorough DNA tests.

Those pages had quite a lot to say about their creation and history. The tests revealed 1000-year-old genetic material from the cows and sheep that gave the book its parchment pages. Remarkably, the DNA was so intact that the scientists could identify the cows' ancestry (something close to our modern-day Norwegian reds and Holsteins) and sex (mostly female).

The pages also contained human DNA and even bacteria, most likely from the hands and saliva of the people who made, wrote, and used the book.

Speaking to The Atlantic, parchment expert Bruce Holsinger of the University of Virginia called the findings "an exciting breakthrough."

[h/t The Atlantic]

5 Signs Humans Are Still Evolving

Lealisa Westerhoff, AFP/Getty Images
Lealisa Westerhoff, AFP/Getty Images

When we think of human evolution, our minds wander back to the millions of years it took natural selection to produce modern-day man. Recent research suggests that, despite modern technology and industrialization, humans continue to evolve. "It is a common misunderstanding that evolution took place a long time ago, and that to understand ourselves we must look back to the hunter-gatherer days of humans," Dr. Virpi Lummaa, a professor at the University of Turku, told Gizmodo.

But not only are we still evolving, we're doing so even faster than before. In the last 10,000 years, the pace of our evolution has sped up, creating more mutations in our genes, and more natural selections from those mutations. Here are some clues that show humans are continuing to evolve.

1. Humans drink milk.

Historically, the gene that regulated humans' ability to digest lactose shut down as we were weaned off our mothers' breast milk. But when we began domesticating cows, sheep, and goats, being able to drink milk became a nutritionally advantageous quality, and people with the genetic mutation that allowed them to digest lactose were better able to propagate their genes.

The gene was first identified in 2002 in a population of northern Europeans that lived between 6000 and 5000 years ago. The genetic mutation for digesting milk is now carried by more than 95 percent of northern European descendants. In addition, a 2006 study suggests this tolerance for lactose developed again, independently of the European population, 3000 years ago in East Africa.

2. We're losing our wisdom teeth.

Our ancestors had much bigger jaws than we do, which helped them chew a tough diet of roots, nuts, and leaves. And what meat they ate they tore apart with their teeth, all of which led to worn-down chompers that needed replacing. Enter the wisdom teeth: A third set of molars is believed to be the evolutionary answer to accommodate our ancestors' eating habits.

Today, we have utensils to cut our food. Our meals are softer and easier to chew, and our jaws are much smaller, which is why wisdom teeth are often impacted when they come in — there just isn't room for them. Unlike the appendix, wisdom teeth have become vestigial organs. One estimate says 35 percent of the population is born without wisdom teeth, and some say they may disappear altogether.

3. We're resisting infectious diseases.

In 2007, a group of researchers looking for signs of recent evolution identified 1800 genes that have only become prevalent in humans in the last 40,000 years, many of which are devoted to fighting infectious diseases like malaria. More than a dozen new genetic variants for fighting malaria are spreading rapidly among Africans. Another study found that natural selection has favored city-dwellers. Living in cities has produced a genetic variant that allows us to be more resistant to diseases like tuberculosis and leprosy. "This seems to be an elegant example of evolution in action," says Dr. Ian Barnes, an evolutionary biologist at London's Natural History Museum, said in 2010 statement. "It flags up the importance of a very recent aspect of our evolution as a species, the development of cities as a selective force."

4. Our brains are shrinking.

While we may like to believe our big brains make us smarter than the rest of the animal world, our brains have actually been shrinking over the last 30,000 years. The average volume of the human brain has decreased from 1500 cubic centimeters to 1350 cubic centimeters, which is an amount equivalent to the size of a tennis ball.

There are several different conclusions as to why this is: One group of researchers suspects our shrinking brains mean we are in fact getting dumber. Historically, brain size decreased as societies became larger and more complex, suggesting that the safety net of modern society negated the correlation between intelligence and survival. But another, more encouraging theory says our brains are shrinking not because we're getting dumber, but because smaller brains are more efficient. This theory suggests that, as they shrink, our brains are being rewired to work faster but take up less room. There's also a theory that smaller brains are an evolutionary advantage because they make us less aggressive beings, allowing us to work together to solve problems, rather than tear each other to shreds.

5. Some of us have blue eyes.

Originally, we all had brown eyes. But about 10,000 years ago, someone who lived near the Black Sea developed a genetic mutation that turned brown eyes blue. While the reason blue eyes have persisted remains a bit of a mystery, one theory is that they act as a sort of paternity test. “There is strong evolutionary pressure for a man not to invest his paternal resources in another man’s child,” Bruno Laeng, lead author of a 2006 study on the development of blue eyes, told The New York Times. Because it is virtually impossible for two blue-eyed mates to create a brown-eyed baby, our blue-eyed male ancestors may have sought out blue-eyed mates as a way of ensuring fidelity. This would partially explain why, in a recent study, blue-eyed men rated blue-eyed women as more attractive compared to brown-eyed women, whereas females and brown-eyed men expressed no preference.

Now Ear This: A New App Can Detect a Child's Ear Infection

iStock.com/Techin24
iStock.com/Techin24

Generally speaking, using an internet connection to diagnose a medical condition is rarely recommended. But technology is getting better at outpacing skepticism over handheld devices guiding decisions and suggesting treatment relating to health care. The most recent example is an app that promises to identify one of the key symptoms of ear infections in kids.

The Associated Press reports that researchers at the University of Washington are close to finalizing an app that would allow a parent to assess whether or not their child has an ear infection using their phone, some paper, and some soft noises. A small piece of paper is folded into a funnel shape and inserted into the ear canal to focus the app's sounds (which resemble bird chirps) toward the child’s ear. The app measures sound waves bouncing off the eardrum. If pus or fluid is present, the sound waves will be altered, indicating a possible infection. The parent would then receive a text from the app notifying them of the presence of buildup in the middle ear.

The University of Washington tested the efficacy of the app by evaluating roughly 50 patients scheduled to undergo ear surgery at Seattle Children’s Hospital. The app was able to identify fluid in patients' ears about 85 percent of the time. That’s roughly as well as traditional exams, which involve visual identification as well as specialized acoustic devices.

While the system looks promising, not all cases of fluid in the ear are the result of infections or require medical attention. Parents would need to evaluate other symptoms, such as fever, if they intend to use the app to decide whether or not to seek medical attention. It may prove most beneficial in children with persistent fluid accumulation, a condition that needs to be monitored over the course of months when deciding whether a drain tube needs to be placed. Checking for fluid at home would save both time and money compared to repeated visits to a physician.

The app does not yet have Food and Drug Administration (FDA) approval and there is no timetable for when it might be commercially available. If it passes muster, it would join a number of FDA-approved “smart” medical diagnostic tools, including the AliveKor CardiaBand for the Apple Watch, which conducts EKG monitoring for heart irregularities.

[h/t WGRZ]

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