Thursday, September 5, 2013

Though bats and toothed whales, who form the suborder of cetaceans, Odontoceti, that including sperm whales and dolphins have no common ancestor for approximately 80 million years, scientists have recently discover that through selective pressures, echolocation evolved convergently in both groups.

By analyzing as many sites as possible across currently mapped genomic sequence data, the scientists were able to show that convergence can be a widespread process involving multiple loci within genes that interrelate and coevolve. Close to 200 loci were identified as linked to genetic convergence and many of the identified genes that are implicated specifically to convergent evolution in echolocation are linked to hearing or deafness. This ultimately provides significant support for the convergent evolution of echolocation in both bottlenose dolphins and bats.

Also found were convergence in many genes linked to vision which were correlated with the pressure linked to the drive of natural selection. As echolocation is particularly useful in environments where visual information is impaired or limited, this link may not be such a surprise.

Ultimately the researchers noted that the process of convergent evolution is not an infrequent process that drives exclusive sections of a genome and can be examined at the molecular level by examining its widespread effects across multiple sites across the genetic code. Examining the genes with the highest levels of convergence and examining their function or functions would be the next step.

Image and educational source: http://askabiologist.asu.edu/echolocation

Sources:
Parker, J., Tsagkogeorga, G., Cotton, J. A., Liu, Y., Provero, P., Stupka, E., & Rossiter, S. J. (2013). Genome-wide signatures of convergent evolution in echolocating mammals, Nature doi:10.1038/nature12511 http://www.nature.com/nature/journal/vaop/ncurrent/full/nature12511.html
http://www.nature.com/news/convergent-evolution-seen-in-hundreds-of-genes-1.13679
http://www.the-scientist.com/?articles.view%2FarticleNo%2F37350%2Ftitle%2FSurprising-Similarities-in-Divergent-Genomes%2F

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