Por que a vida complexa evoluiu, provavelmente, apenas uma vez?

quinta-feira, outubro 21, 2010

Nature 467, 929-934 (21 October 2010) | doi:10.1038/nature09486; Published online 20 October 2010

The energetics of genome complexity

Nick Lane1 & William Martin2

All complex life is composed of eukaryotic (nucleated) cells. The eukaryotic cell arose from prokaryotes just once in four billion years, and otherwise prokaryotes show no tendency to evolve greater complexity. Why not? Prokaryotic genome size is constrained by bioenergetics. The endosymbiosis that gave rise to mitochondria restructured the distribution of DNA in relation to bioenergetic membranes, permitting a remarkable 200,000-fold expansion in the number of genes expressed. This vast leap in genomic capacity was strictly dependent on mitochondrial power, and prerequisite to eukaryote complexity: the key innovation en route to multicellular life.


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