Re-winding Evolution

Looking back on the evolutionary history of life it can often seem like a long series of accidents. However, if we wound back time millions of years and started evolution again would we end up in the same place? It was this incredibly interesting question that was first asked by the famous Yale professor Stephen Jay Gould. His thought experiment was simple: if we re-wound the tape of life, would it evolve again in the same way? Would the long and complex path that life’s evolutionary history has taken be replicated, or would we find ourselves in a world very different to the one in which we currently reside?

Though several answers to this question have been suggested, scientists at Georgia Tech University in Atalanta are attempting to find out once and for all, by ‘rewinding the tape of life’ using experimental microbiology. To do this, researchers Eric Gaucher and Betül Arslan used a 500 million year old gene taken from Escherichia coli bacteria, called EF-Tu. The aim was to insert this ancient gene in place of the modern E.coli gene and see how  it ‘evolved’ over numerous generations. Comparing the modern genome and the newly ‘evolved’ sequence could provide valuable information about the course that evolution takes.

Initially the pair observed that bacteria containing the ancient gene grew far more slowly than their modern descendents. However, after having let eight bacterial lines evolve independently for 1000 generations they found that all of the lineages began to grow faster, a clear sign that evolution had occurred within the genome. Suprisingly, the gene thought to be cause of the evolution, EF-Tu, remained unchanged and it was found that it was in fact the genes that interact with EF-Tu that had evolved differently in each lineage. This has further highlighted the importance of gene interaction in protein synthesis; though the genes might be ‘selfish’ it is often forgotten that they rarely act alone.

The initial findings were recently presented at NASA’s Astrobiology Science Conference 2012, held in Atalanta, but the pair continue their work to see what other twists and turns this road of evolution might uncover. Watch this space…