About 100 million years ago, a lowly amoeba pulled off a stunning heist, grabbing genes from an unsuspecting bacterium to replace those it had lost.
Now Rutgers and other scientists have solved the mystery of how the little amoeba, Paulinella, committed the theft. It engulfed the bacterium, kept that cell alive and harnessed its genes for photosynthesis, the process plants and algae use to convert carbon dioxide into oxygen and sugar via solar energy.
In the new study, scientists examined Paulinella to learn the rules of genome evolution that allowed photosynthesis to take hold and flourish. The rules could be revealed because the Paulinella endosymbiosis took place 100 million years ago, using the same process that unfolded about 1.5 billion years ago.
Using this unique model, the researchers asked a critical question about endosymbiosis that had dogged scientists for many years. It has long been known that cells kept inside other cells can no longer share DNA with their own species and tend to build up a lot mutations in their genome, leading to their demise.
This decay process is called Muller’s ratchet. So how did the captured plastid escape the ratchet after millions of years of imprisonment? Analysis of Paulinella genomic data showed that every time it lost a gene, the amoeba replaced it with another gene with the same function from bacteria.
http://news.rutgers.edu/research-news/little-amoeba-committed-grand-theft/20161010#.V_4JEOV97IX
Now Rutgers and other scientists have solved the mystery of how the little amoeba, Paulinella, committed the theft. It engulfed the bacterium, kept that cell alive and harnessed its genes for photosynthesis, the process plants and algae use to convert carbon dioxide into oxygen and sugar via solar energy.
In the new study, scientists examined Paulinella to learn the rules of genome evolution that allowed photosynthesis to take hold and flourish. The rules could be revealed because the Paulinella endosymbiosis took place 100 million years ago, using the same process that unfolded about 1.5 billion years ago.
Using this unique model, the researchers asked a critical question about endosymbiosis that had dogged scientists for many years. It has long been known that cells kept inside other cells can no longer share DNA with their own species and tend to build up a lot mutations in their genome, leading to their demise.
This decay process is called Muller’s ratchet. So how did the captured plastid escape the ratchet after millions of years of imprisonment? Analysis of Paulinella genomic data showed that every time it lost a gene, the amoeba replaced it with another gene with the same function from bacteria.
http://news.rutgers.edu/research-news/little-amoeba-committed-grand-theft/20161010#.V_4JEOV97IX