wildcat2030:

This Bizarre Organism Builds Itself a New Genome Every Time It Has Sex - Oxytricha trifallax lives in ponds all over the world. Under an electron microscope it looks like a football adorned with tassels. The tiny fringes are the cilia it uses to move around and gobble up algae. What makes Oxytricha unusual, however, is the crazy things it does with its DNA. Unlike humans and most other organisms on Earth, Oxytricha doesn’t have sex to increase its numbers. It has sex to reinvent itself. When its food is plentiful, Oxytricha reproduces by making imperfect clones of itself, much like a new plant can grow from a cutting. “If they’re well fed, they won’t mate,” said Laura Landweber, a molecular biologist at Princeton University and lead author of a recent study on Oxytricha genetics. But when Oxytricha gets hungry or stressed, it goes looking for sex. When two cells come together (as in the image above), the ultimate result is: two cells. “They’ve perfected the art of sex without reproduction,” Landweber said. The exterior of the two cells remains, but each cell swaps half of its genome with the other. “They’re entering into this pact where each one is going to be 50 percent transformed,” Landweber said. “They emerge with a rejuvenated genome.” In size, Oxytricha’s genome is roughly comparable to ours. It has about 18,500 genes, compared to 20,000 or so for humans. But that’s one of the few things we have in common with this pond-dwelling protist. Unlike the cells of plants and animals (fungi too, for that matter), an Oxytricha cell has at least two nuclei. “You can see them under the microscope if you stain for DNA,” Landweber said. One nucleus contains a working copy of the genome—all the DNA it uses to make the RNA and proteins essential for everyday life. Last year, Landweber’s team discovered that the DNA in Oxytricha’s working nucleus is partitioned into approximately 16,000 “nanochromosomes,” most containing just a single gene. It’s a staggering number—most common plants and animals have somewhere between a dozen and a hundred chromosomes (we humans have 23 pairs). (via This Bizarre Organism Builds Itself a New Genome Every Time It Has Sex | WIRED)

“They’ve perfected the art of sex without reproduction,” Landweber said. The exterior of the two cells remains, but each cell swaps half of its genome with the other. “They’re entering into this pact where each one is going to be 50 percent transformed,”That’s sexy.
me: i am actually so happy with my life right now for once next day: *everything fucks up*
wildcat2030:

Richard Feynman: no one has said it better..
“Who can live without some black clothes.”
“vaccinate your fucking kids”
moelskerdeg: humnoo: a-pariah: why is the female hero so often tomboyish why cant there just be one like oops i chipped my barbie pink nail polish while brutally killing an entire armada of time traveling ninja pirates with my hair curler Um… #it’s like so many people want buffy and just don’t know it yet (via twd-sisters-are-reunited)

moelskerdeg:

humnoo:

a-pariah:

why is the female hero so often tomboyish

why cant there just be one like oops i chipped my barbie pink nail polish while brutally killing an entire armada of time traveling ninja pirates

with my hair curler

Um…

image

(via twd-sisters-are-reunited)