A LONG-TERM STUDY ON SEASONAL CHANGES OF GAMETIC DISEQUILIBRIUM BETWEEN ALLOZYMES AND INVERSIONS IN DROSOPHILA SUBOBSCURA

Abstract

Seasonal variation (spring, early summer, late summer, and autumn) of gametic disequilibrium between gene arrangements (OST and O3+4) of the O chromosome and Lap, Pept-1, and Acph allozyme loci, located inside these inversions, has been recorded in a natural population of Drosophila subobscura during seven years over a 15-year period. The length of the study allowed us to investigate the temporal variation of the allozyme-inversion associations by statistical methods of time series analysis. Cyclic seasonal changes of allozyme-inversion associations for both Lap and Pept-1 are detected in the natural population. In both cases, the patterns of seasonal change are due to the seasonal change of frequency of Lap and Pept-1 allozymes occurring exclusively within the OST gene arrangement. In contrast, the allozyme frequencies at these loci within the O3+4 gene arrangement are stable along seasons. The patterns of temporal variation of allozyme-inversion associations for Lap and Pept-1 in the natural population are contrasted with those previously published that correspond to gene arrangements of the O chromosome and nucleotide polymorphism at the rp49 region located inside these inversions, suggesting that natural selection is operating on these allozyme-inversion associations.