The genetic diversity of eastern North American tree species as related to the extent of their spatial distribution during the Last Glacial Maximum

Abstract

The distribution of boreal and temperate species during the last glacial maximum (LGM) in Eastern North America can have a significant effect on the genetic diversity of present day populations. Here, I modelled the LGM distribution of several keystone deciduous tree species native to northeastern North America. The ecological niche modelling software, Maxent, was used to generate a relative rate of occurrence that was used to infer the probable locations of glacial refugia. These predicted refugia were then validated by paleo-ecological records where available. The genetic variation of each species was assessed by a literature review of previous studies that used allozymes to determine the expected heterozygosity. The area of the refugia were then compared to the expected heterozygosity through a linear regression. The findings of this study indicated no significant relationship (r2 = 0.024) between refugia size and expected heterozygosity. The lack of data on expected heterozygosity likely skewed the results and further studies need to be conducted to correct for this.