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Tanaka S, Sagara H, Kunieda.
Tanaka S, Sagara H, Kunieda.

Water Bears’ DNA Makes Them Practically Indestructible

Tanaka S, Sagara H, Kunieda.
Tanaka S, Sagara H, Kunieda.

Burn it. Freeze it. Chuck it into space. Water bear don’t care. The water bear, also known as the tardigrade or moss piglet, is one of the weirdest and toughest creatures on the planet. Now new research published in the journal Nature Communications suggests we might someday be able to borrow its resilience to use in our own flimsy, floppy bodies.

Tardigrades are extremophiles—that is, they can keep trucking in unbelievably hostile environments, from scorching deserts to the vacuum of space. This astonishing near-indestructibility has, understandably, made them especially appealing to scientists, who have been working for years to pick apart the genetic basis of the microscopic creatures’ badassery. But the more we learn about these creatures, the weirder they seem to get.

In 2015, a group of researchers reported one possible source of the tardigrade’s toughness: burglary. While looking at the genome of the tardigrade species Hypsibius dujardini, the team said they found all kinds of genes that belonged to other organisms, including fungi and bacteria. Horizontal gene transfer (when one organism swipes genes from another) is not unheard of, but H. dujardini appeared to have taken it to the next level, with a full 17 percent of its genes yoinked from other species.

Even for the moss piglet, this seemed kind of, well, extreme. When other scientists tried to replicate the original team’s results, they found only tiny amounts of horizontal gene transfer—about 1 or 2 percent. They said the original team’s samples had likely been contaminated. #tardigate ensued. The tardigrade remained a tiny, scrappy enigma.

Scientists kept at it. The latest research, published today, may have cracked some of the mystery. Researchers in Japan examined the genome of an especially hardy water bear named Ramazzottius varieornatus. In comparing the tardigrade’s genetic codes with those of worms and flies, they found way more genes related to surviving stressful conditions.

In the video below, by researcher Daiki D. Horikawa, you can see R. varieornatus encounter one stressful condition: a lack of water. The tardigrade dries out and shrinks up, seemingly dead. But it isn't. Given a drop of water, it plumps right up, stretches its little legs, and begins to move around.

Then the team took the study to the next level. They found a resilience-boosting protein they called Damage suppressor (Dsup) that appears to be completely unique to tardigrades. Then they inserted Dsup into human cells, which then became more resistant to damage from x-ray radiation.

There’s a lot here to get excited about, says Sujai Kumar, a genome informatician at the University of Edinburgh and a co-author on the #tardigate-triggering study. “The Japanese team's genome sequencing methodology is exemplary,” he tells mental_floss. The depth and breadth of their investigation have yielded a huge quantity of information that will continue to help other researchers unravel the tardigrade mystery.

Even better, Kumar says, were the Japanese researchers’ “really cool” studies in human cells. “Although not quite at the level of a superheroine origin story,” he says, “this is a great example of a gene from an extremotolerant species conferring a 'super power' to a human cell, and is an exciting finding.”

Know of something you think we should cover? Email us at tips@mentalfloss.com.

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Animals
Where Do Birds Get Their Songs?
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iStock

Birds display some of the most impressive vocal abilities in the animal kingdom. They can be heard across great distances, mimic human speech, and even sing using distinct dialects and syntax. The most complex songs take some practice to learn, but as TED-Ed explains, the urge to sing is woven into songbirds' DNA.

Like humans, baby birds learn to communicate from their parents. Adult zebra finches will even speak in the equivalent of "baby talk" when teaching chicks their songs. After hearing the same expressions repeated so many times and trying them out firsthand, the offspring are able to use the same songs as adults.

But nurture isn't the only factor driving this behavior. Even when they grow up without any parents teaching them how to vocalize, birds will start singing on their own. These innate songs are less refined than the ones that are taught, but when they're passed down through multiple generations and shaped over time, they start to sound similar to the learned songs sung by other members of their species.

This suggests that the drive to sing as well as the specific structures of the songs themselves have been ingrained in the animals' genetic code by evolution. You can watch the full story from TED-Ed below, then head over here for a sample of the diverse songs produced by birds.

[h/t TED-Ed]

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Animals
Watch the First-Ever Footage of a Baby Dumbo Octopus
NOAA, Wikimedia Commons // Public Domain
NOAA, Wikimedia Commons // Public Domain

Dumbo octopuses are named for the elephant-ear-like fins they use to navigate the deep sea, but until recently, when and how they developed those floppy appendages were a mystery. Now, for the first time, researchers have caught a newborn Dumbo octopus on tape. As reported in the journal Current Biology, they discovered that the creatures are equipped with the fins from the moment they hatch.

Study co-author Tim Shank, a researcher at the Woods Hole Oceanographic Institution in Massachusetts, spotted the octopus in 2005. During a research expedition in the North Atlantic, one of the remotely operated vehicles he was working with collected several coral branches with something strange attached to them. It looked like a bunch of sandy-colored golf balls at first, but then he realized it was an egg sac.

He and his fellow researchers eventually classified the hatchling that emerged as a member of the genus Grimpoteuthis. In other words, it was a Dumbo octopus, though they couldn't determine the exact species. But you wouldn't need a biology degree to spot its resemblance to Disney's famous elephant, as you can see in the video below.

The octopus hatched with a set of functional fins that allowed it to swim around and hunt right away, and an MRI scan revealed fully-developed internal organs and a complex nervous system. As the researchers wrote in their study, Dumbo octopuses enter the world as "competent juveniles" ready to jump straight into adult life.

Grimpoteuthis spends its life in the deep ocean, which makes it difficult to study. Scientists hope the newly-reported findings will make it easier to identify Grimpoteuthis eggs and hatchlings for future research.

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