MtDNA not marker of population size

Mitochondrial genetic diversity may be influenced by natural selection, undermining its utility for population genetics research

Charles Choi
One of the most widely used markers in population genetics, mitochondrial genetic diversity, does not accurately reflect the size and history of a population, according to a report in this week's Science. This suggests natural selection may be acting on mitochondrial DNA (mtDNA), the authors note."This result opens questions -- what is mtDNA adapting to?" co-author Nicolas Galtier at the University of Montpellier in France told The Scientist.MtDNA is widely believed to be nearly evolutionary neutral. Therefore, mitochondrial genetic diversity should increase as a species' population size increases, and looking at mtDNA diversity should enable researchers to infer whether a species is advancing or declining.In the present study, the researchers assembled a database dedicated to sequence polymorphism by scanning GenBank and EMBL-Bank. To check its reliability, they compared the resulting information on the nuclear DNA of 417 species and the mtDNA of 1,683 species with allozyme data for...

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