Genetic variation in insular populations of the eastern woodrat, (Neotoma Floridana) in a forest-prairie mosaic.

Abstract

The genetic makeup of a population is strongly dependent upon the dispersal patterns among the demes within that population. Dispersal allows gene flow to occur among demes, and lack of it allows genetic drift to cause differentiation to occur among demes. A forest-prairie ecotone exists in eastern Kansas. Many of the wooded areas house insular populations of eastern woodrats (Neotoma floridana attwateri). The purpose of my study was to determine dispersal rates among these insular populations as well as to add to the knowledge of the genetics of eastern woodrats. The hypotheses were: 1) there is limited dispersal among demes; and 2) the smaller and the more distant demes are more divergent genetically than those larger or closer to the main population. Electrophoresis was performed on eastern woodrat ear tissue. Four out of 19 loci were polymorphic. Neils genetic distance ranged from 0.000 to 0.001. with Neils distance coefficients this low, no determination could be made concerning dispersal among demes. The genetic differentiation among demes was essentially nonexistent. Eastern woodrats are thought tohave undergone a significant bottleneck about 10,000 ybp, which resulted in reduced genetic variability in these rats in the western and northern portions of their range. With this overall low genetic variability and more recent localized bottlenecks within the patchy habitat in Kansas, there still remains little genetic diversity within the eastern woodrats of Kansas.