Natural distributions of mitochondrial sequence diversity support new null hypotheses.
A variety of forces and constraints can cause sequence data to deviate from patterns predicted under strict neutrality. Here, I present a meta-analysis of available aligned sequence data from 12 higher animal taxa to identify whether the typical null assumption for an often-used test for neutrality--Tajima's D statistic--is an appropriate or useful null given large numbers of empirical observations. Across 1068 cytochrome oxidase I (COI) datasets, the mean value for Tajima's D is -0.391, with over a sixth of these datasets representing "significant" divergence from null assumptions according to this test. These results indicate a persistent trend for mitochondrial COI data--chosen for their prevalence in population and taxonomic studies--to indicate patterns of diversity that deviate from a purely neutral description, and provide compelling support for the concept that more complex "null" hypotheses may be necessary in population genetics.
Department of Genetics, University of Georgia, Athens, Georgia 30602, USA. jpwares@uga.edu
John P
JP
Wares
D000818:Animals; D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV / Q000235:genetics*; D019143:Evolution, Molecular; D014644:Genetic Variation
D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV