Dit is hoe ze het doen:Death is the ultimate fate for most bacteria blasted by huge doses of radiation or parched by a severe lack of water. The genetic material irreversibly splinters into hundreds of pieces, dooming the organisms as surely as Humpty Dumpty.
But a few bacteria can "resurrect" themselves by quickly piecing their DNA back together. "There is no metabolism," Radman said. "The genome is shattered into hundreds of pieces. It is a dead cell.
"But out of this horrendous damage, it can resurrect."http://news.nationalgeographic.com/news/20...surrection.html
Is het mogelijk dat zo'n mechanisme ook betrokken is bij het ontstaan van het leven?D. radiodurans contains multiple copies of its genetic material, which can act as backups for each other, Radman says. Imagine that a cell's DNA holds the message "Humpty Dumpty sat on a wall, Humpty Dumpty had a great fall." Since the spots where DNA breaks because of radiation or damage are random, each copy of the genetic material will likely have breaks in unique locations.
So if one DNA strand breaks into the split messages "Humpty Dumpty sat on a wall" and "Humpty Dumpty had a great fall," there's likely another chunk of material floating around that can bridge the gap. The material might read "sat on a wall, Humpty Dumpty," for example.
The bacteria then chemically glue matching pieces together. Once they're bound, the cells fill in the missing parts of each of the two stuck-together copies, the study shows. Using such clues, D. radiodurans can piece together all of its DNA in about three hours, even if it was split into hundreds of pieces.
Ze zeggen dat de bacterie dood is en vervolgens zijn DNA weer in elkaar puzzelt en tot leven komt, is dit niet een vorm van abiogenesis?
En ja ik weet dat de DNA stukken in dit geval al aanwezig waren, dus het verklaart niet de oorsprong van DNA, maar het gaat hier om het chemische mechanisme, en misschien is dit mechanisme niet afhankelijk van DNA.
