Selection and gene flow between microenvironments:: The case of Drosophila at Lower Nahal Oren, Mount Carmel, Israel

Drosophila melanogaster and D. simulans from contrasted microenvironments (south- and north-facing slopes of Lower Nahal Oren Canyon in Israel) were tested for genetic differentiation at microsatellite loci, which might be linked to differential adaptation to local ecological factors. No overall genetic differentiation was observed in either species. This indicates that the contrasted selective pressures on the two sides of the valley are not strong enough to cause population subdivision in highly mobile species such as Drosophila . Significant differences in allele frequencies were observed at two microsatellite loci, but on the whole the level of divergence we observed is far lower than has been reported previously.