500-million-year-old gene spliced into modern bacteria
Biologists at Georgia Tech have resurrected a 500-million-year-old gene from bacteria and inserted it into modern Escherichia coli (E.coli) bacteria. The researchers have observed the bacterium grow over more than 1,000 generations, allowing them to see "evolution in action".
In a process called paleo-experimental evolution,Betül Kaçar, a Nasa astrobiology postdoctoral fellow in Georgia Tech's Nasa Centre for Ribosomal Origins and Evolution, built on work by his advisor Eric Gaucher to take the ancient genetic sequence of the Elongation Factor-Tu (EF-Tu) protein -- one of the most abundant proteins in bacteria and required for bacteria to survive -- and inserting in the correct chromosomal order within modern E-coli. Kaçar produced eight identical strains and let the "ancient life" re-evolve. This chimeric bacteria survived, but grew about twice as slowly as its modern counterpart.
"This is as close as we can get to rewinding and replaying the molecular tape of life. The ability to observe an ancient gene in a modern organism as it evolves within a modern cell allows us to see whether the evolutionary trajectory once taken will repeat itself or whether a life will adapt following a different path," said Kaçar.
After an initial slow growth rate, the bacteria strains started to speed up. After the first 500 generations, the team sequenced the genomes of the eight lineages to see how they had adapted. It turned out that the bacteria's fitness levels had increased to almost modern-day levels and some of the strains had even become healthier than their modern counterpart.
The spliced gene, however, did not mutate. The modern proteins that interact with the ancient Ef-Tu inside the bacteria had done, however. That is to say that the ancient gene has not mutated to be more similar to its modern form; instead the bacteria has found a new evolutionary trajectory.
The results were presented at the Nasa International Astrobiology Science Conference. The team will continue to study the generations, waiting to see whether the protein will follow its historical path or adapt a new one.
Kaçar explained: "We want to know if an organism's history limits its future and if evolution always leads to a single, defined point or whether evolution has multiple solutions to a given problem."
Source: http://www.wired.co.uk/news/archive/2012-07/13/ancient-gene-inserted-into-e-coli
Hope this doesn't end up like Jurassic Park