Genome Of Animal That Can Live On In Space Is Made Up Of One-Sixth Foreign DNA
There is a tiny life form that does something none other can do, perhaps. It survives in outer space.
Amazingly, research shows that a large portion of its genome comes from "foreign" DNA.
When researchers sequenced its genome, they found that it consists of 17.5 percent foreign DNA, according to the University of North Carolina at Chapel Hill.
"We had no idea that an animal genome could be composed of so much foreign DNA," said co-author Bob Goldstein, faculty in the biology department in UNC's College of Arts and Sciences. "We knew many animals acquire foreign genes, but we had no idea that it happens to this degree."
Hence, the tardigrades have gained 6,000 foreign genes primarily from bacteria, plants, fungi and Archaea through the "horizontal gene transfer". It explains the link between foreign DNA and its capacity to survive harsh situations.
"Animals that can survive extreme stresses may be particularly prone to acquiring foreign genes-and bacterial genes might be better able to withstand stresses than animal ones," Boothby said.
Hence, a tardigrade can live for a year in a freezer. It begins to move just 20 minutes after it thaws. Researchers believe that the tardigrades can live on even after these harsh conditions if their DNA splits into tiny pieces. They can be repaired after they come back to normal situations.
"We think of the tree of life, with genetic material passing vertically from mom and dad," Boothby said. "But with horizontal gene transfer becoming more widely accepted and more well known, at least in certain organisms, it is beginning to change the way we think about evolution and inheritance of genetic material and the stability of genomes. So instead of thinking of the tree of life, we can think about the web of life and genetic material crossing from branch to branch. So it's exciting. We are beginning to adjust our understanding of how evolution works."
The study has been published in the recent edition of the Proceedings of the National Academy of Scientists.