Mammals have to contend with shrinking genomes too
July 28th, 2009 - 2:49 pm ICT by IANSWashington, July 28 (IANS) After the dinosaurs, mammals too have to contend with a shrinking genome, according to evidence buried in the chromosomes of animals and plants.
There was a shrinking in the genomes of the dinosaurs before they went extinct. This trend continues today in the case of mammals, say Indiana University-Bloomington (IU-B) scientists.
The finding might seem counter-intuitive, given that the last 65 million years have seen mammals expand in diversity and number, not to mention dominance in a wide variety of ecological roles.
But it is precisely their success in numbers that could have led to the contraction of their genomes. “Larger population sizes make natural selection more efficient,” said IU-B evolutionary biologist Michael Lynch, who led the study.
“If we are correct, we have shown how to bring ancient genomic information together with the palaeontological record to learn more about the past,” said Lynch.
Lynch says the data he and his colleagues analysed suggest human genomes are still undergoing a contraction — though humans shouldn’t expect to see noticeable changes in their chromosomes for a few million years yet.
The study was published in the inaugural issue of the journal Genome Biology and Evolution.
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Tags: 65 million years, animals and plants, chromosomes, colleagues, contraction, dinosaurs, diversity, dominance, ecological roles, evolutionary biologist, genome biology, human genomes, inaugural issue, indiana university bloomington, iu, mammals, natural selection, noticeable changes, population sizes, scientists
