A 500-million-year-old bacterial gene got a second chance at evolution this year. The experiment may help biologists understand the extent to which evolution is predictable.
Biologists have long wondered whether life would evolve the same way again if we could rewind the tape. Eric Gaucher and Bet?l Arslan at Georgia Tech University in Atlanta hope to find out.
They focused on EF-Tu, a gene in Escherichia coli that plays a crucial role in protein synthesis. Gaucher had previously worked out what this gene's DNA sequence must have been 500 million years ago, by comparing the sequences of many modern bacteria and reasoning backwards.
Now Arslan has synthesised the ancient gene and inserted it into E. coli in place of the modern version. The bacteria with the old gene grew less than half as fast as usual. Arslan then let eight bacterial lines evolve independently for 1000 generations.
All eight lineages eventually grew faster - a sign that evolution had occurred. When Arslan sequenced their genomes, though, she found that EF-Tu was unchanged. What had evolved - differently in each lineage - were the genes that interact with EF-Tu. She reported the work at NASA's Astrobiology Science Conference 2012 in Atlanta.
The sheer number of interacting genes in protein synthesis means that random mutations are more likely to hit one of EF-Tu's partners than EF-Tu itself. Eventually, though, EF-Tu may begin to evolve - either following the same path it began 500 million years ago or not. The experiment continues.
If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.
Have your say
Only subscribers may leave comments on this article. Please log in.
Only personal subscribers may leave comments on this article
Subscribe now to comment.
All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.
If you are having a technical problem posting a comment, please contact technical support.
michelle obama adam lambert arrested shroud of turin barkley
কোন মন্তব্য নেই:
একটি মন্তব্য পোস্ট করুন