Document: PAU-3-46-14

Population genetic parameters vary latitudinally within species: Implications for variation in speciation and extinction rates.

MARTIN, P.R.* and J.K.MCKAY

University of Montana, Missoula, MT 59812 USA ¹

Abstract:
Species richness declines with increased latitude in most taxa on a variety of spatial scales. This gradient in species richness may result from latitudinal variation in speciation and extinction rates, which influence and are influenced by population genetic parameters. Specifically, if speciation rates are currently higher in the tropics, then genetic isolation by distance of populations should be greater among lower latitude populations. Conversely, if recent extinctions and near-extinctions were greater at higher latitudes, population bottlenecks should have reduced variation within high latitude populations. We tested these predictions using within-species patterns of genetic variation in mtDNA from diverse vertebrate taxa whose distributions span a broad range of latitudes. We found greater isolation by distance at lower latitudes, suggesting reduced gene flow and higher incipient speciation; however, within population genetic variation showed no latitudinal pattern.

Keywords: latitude, species richness, speciation, extinction

This abstract is being presented at: 4:15 PM in session:
Oral Session #63: Evolutionary Ecology.