Polymorphic Inversion and Esterase Loci Complex on Chromosome 2 of Drosophila buzzatii II. Spatial Variation

Abstract

The potential influence of linked inversions on allele frequency variation at the Est-l and Est-210ci among Australian populations of D. buzzatii was determined by statistical analyses of allele and inversion gametic frequencies. Most of the significant spatial and climatic associations found for all Est-l allele frequencies, and for one allele only of Est-2 (Est-2c+), were accounted for by their linkage disequilibria with the inversions, which covaried with environmental variables. Consistent with this result, the spatial and climatic associations for conditional Est-l and Est-2 allele frequencies tended to be different from those for the respective unadjusted allele frequencies. In one important respect, the results for Est-l and Est-2 were not altered by inversions. For both unadjusted and conditional Est-l allele frequencies, few climatic associations remain after correcting for geographic location, whereas for both unadjusted and conditional Est-2 allele frequencies, climatic associations remain after correcting for geographic location. Thus, apparent selection affecting allele frequencies at the Est-2 locus is not accounted for by linked inversions.