Comparative Genetic Structure between Tropical Colombian and North American Drosophila pseudoobscura Populations1

Abstract

Abstract Since the discovery of Drosophila pseudoobscura in the tropical highlands of the Colombian Andes during the 1960s, this population has been studied by many evolutionary biologists because of its geographical isolation from the main North American range of this species. We used five highly variable microsatellite loci (DPSX001, DPS2001, DPS3001, DPS3002, and DPS4001) to analyze the genetic structure of three Colombian populations and the genetic relationships with four North American populations. We found that the average heterozygosity was consistent among the three tropical Colombian populations (H = 0.665–0.675), but they had less variability than their North American counterparts. Nonetheless, the genic diversity found in the Colombian populations was higher than that found previously using other genetic markers. The average genic heterogeneity estimate among the Colombian populations (RST = 0.042), although statistically significant, was substantially lower than that found among the North Ame...