Posted on 11/28/2015 7:54:46 AM PST by rickmichaels
Everything about tardigrades sounds like a riddle: What creature can survive both freezing and boiling temperatures; you can't see it, but it's everywhere; it can survive outer space; and after being dried up for years, it can reanimate in water within a few minutes?
The answer is just as puzzling: tardigrades, which are also called "water bears" or "moss piglets," are aquatic, microscopic invertebrates that have recently captivated evolutionary biologists and science enthusiasts alike for their unique ability to withstand extreme conditions. There is photographic evidence too that tardigrades are adorable.
Now, researchers at the University of North Carolina at Chapel Hill have found another reason to love the tardigrade - it's a genetic marvel. After sequencing the tardigrade's genome, the team discovered that a whopping 17.5 per cent is composed of foreign DNA. By comparison, the previous record-holder was a microscopic animal called the rotifier, which has half as much foreign DNA; most animals have less than one per cent.
The research, which was published this week in the Proceedings of the National Academy of Sciences, is significant because it demonstrates the potential prowess of "horizontal gene transfer" - the process by which genetic material is traded between unrelated species rather than through parental inheritance. The tardigrade's genome includes DNA from plants, fungi and single-celled micro-organisms called Archaea.
The biologists suspect that when a tardigrade encounters a harsh environment, such as severe dryness, its DNA breaks into pieces; when the cell rehydrates, its membrane and nucleus become "leaky" and DNA from other species can enter it. As tardigrades fix their own DNA, they can incorporate foreign material too. "Animals that can survive extreme stresses may be particularly prone to acquiring foreign genes," says Thomas Boothby, the study's first author. Tardigrades may keep the best ones to enhance their survival.
As horizontal gene transfer becomes more understood, researchers are beginning to rethink the proverbial "tree of life" metaphor for how genes are swapped "vertically" from mother and father to child. "Instead we can think about the web of life and genetic material crossing from branch to branch," says Boothby. "So it's exciting. We're just beginning to adjust our understanding of how evolution works." And tardigrades are proving to be the perfect specimen.
That thing looks like a streaker on a wintry day......
wow, incredible!
I’m probably sitting on a few of them right now. Hope
they can fluff back out once I get up and they fall on
the floor. - Oops! You are sitting on some of them also!
Honey badger don’t give a #$@% how tough water bear thinks it is.
'
More info on the world’s toughest creature:
“Boil the 1mm creatures, freeze them, dry them, expose them to radiation and they’re so resilient they’ll still be alive 200 years later.
Water bears can hack temperatures as low as -457 degrees, heat as high as 357 degrees, and 5,700 grays of radiation, when 10-20 grays would kill humans and most other animals.
The animals can also live for a decade without water and even survive in space.”
It that the intake or exhaust?
Where do they live? I didn’t see any information in the article, but I probably missed it. Thanks
Aaaieeeeee!
They’re back for an encore!
/squealing
And now I can’t get “Bang A Gong” out of my head.
Tardigrade “Water bears” are Everywhere.
If you’ve ever had the pleasure of lying down on a bed of moss, there were multitudes of them beneath you.
Good thing they’re friendly!
“small, segmented animals come in many forms - there are more than 900 species of them - and they’re found everywhere in the world, from the highest mountains to the deepest oceans.”
RE: “Where do they live? I didn’t see any information in the article, but I probably missed it. Thanks”
Anywhere there is water...
They can be found in a single drop of dew.
Now it is playing in my ed.
You’re welcome.
:)
They need to be protected. s/
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