The Interaction between Chromosomal Inversion and Recessive Lethals in Drosophila albomicans

Hwei-yu Chang and Fei-Jann Lin (1995) The interac tion between chrom osomal inversion and recessive lethals in Drosophila albomicans. Zoological Studies 34(1): 47-54. In order to reveal the mechanism for the high heterozygosity of an inversion on the left arm of the second chromosome, In(2L)B ,os, several pure lines were established of Drosophil a albomicans for an esterase dimer locus (Est-F). This locus was shown to be eithe r inside the inversion region, or outside, but closely linked with it. By a chromosome extrac tion procedure, we have found that the Wulai D. albomicans populat ion exhibits high heterozygosity (0.54) of the In(2L)B,Ds and that it also has a high frequency of recessive lethals (0.42), but low allelism. These genetic marker strains not only made the chromosome extract ion possible, but were used to reveal that the Wulai popu lation is at linkage equilibrium, whereas the Chitou popu lation is at linkage disequil ibr ium. A possible mechan ism, accumulat ion of recessive lethals in the presence of a chromosomal inversion in a seasonally fluctu ating population, is proposed to explain the phenomena of high inversion heterozygosity, high lethal ity, and low allelism in the Wulai popu lation.