From The Atlantic:
The toughest animals in the world aren’t bulky elephants, or cold-tolerant penguins, or even the famously durable cockroach. Instead, the champions of durability are endearing microscopic creatures called tardigrades, or water bears.
They live everywhere, from the tallest mountains to the deepest oceans, and from hot springs to Antarctic ice. They can even tolerate New York. They cope with these inhospitable environments by transforming into a nigh-indestructible state. Their adorable shuffling gaits cease. Their eight legs curl inwards. Their rotund bodies shrivel up, expelling almost all of their water and becoming a dried barrel called a “tun.” Their metabolism dwindles to near-nothingness—they are practically dead. And in skirting the edge of death, they become incredibly hard to kill.
Scientists have known for centuries about the tardigrades’ ability to dry themselves out. But a new study suggests that this ability might have contributed to their superlative endurance in a strange and roundabout way. It makes them uniquely suited to absorbing foreign genes from bacteria and other organisms—genes that now pepper their genomes to a degree unheard of for animals.
But Boothby found that foreign genes make up 17.5 percent of the tardigrade’s genome—a full sixth. More than 90 percent of these come from bacteria, but others come from archaea (a distinct group of microbes), fungi, and even plants. “The number of them is pretty staggering,” he says. More.
See also: Horizontal gene transfer: Sorry, Darwin, it’s not your evolution any more
How horizontal gene transfer has shaped the web of life “using examples of HGT among prokaryotes, between prokaryotes and eukaryotes, and even between multicellular eukaryotes”
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