The discussion centers on the unique ability of the bacterium D. radiodurans to "resurrect" itself after severe damage, such as radiation exposure or dehydration. This bacterium possesses multiple copies of its genetic material, which serve as backups, allowing it to reconstruct its DNA from fragmented pieces within approximately three hours. The process involves chemically gluing matching DNA segments together and filling in the gaps, raising questions about the implications for the origin of life and potential mechanisms of abiogenesis.
PREREQUISITESResearchers in microbiology, geneticists, and anyone interested in the origins of life and extremophile adaptations will benefit from this discussion.
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."
Is it possible that a mechanism like this is also involved in the origin of life?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.