Genetic Linkage Analysis of Photoperiodic Clock Genes in Chymomyza costata (Diptera : Drosophilidae)

概要

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In a drosophilid fly Chymomyza costata, larval diapause is induced by seasonal photic and thermal cues. Larvae growing under short days and/or low temperatures enter winter diapause at the final (3rd) instar. C. costata is widely distributed in the Holarctic region from 40 to 70°N. The critical photoperiod for diapause induction has a latitudinal cline. It is regulated by the combination of at least two genes which are localized on the X-chromosome and autosome(s). In the present study, the X-linked photoperiodic clock gene (cpp) was mapped by genetic linkage analysis. Genetic crosses were performed between Olekminsk (60°N, 120°E) and Tomakomai (42.5°N, 141.5°E) strains which showed clearly different critical photoperiod. Two X-linked mutant genes were used as genetic markers : a circadian clock mutant period (per) and an eye color mutant garnet (g). Male flies carrying an allele responsible for a short critical photoperiod were selected from F1 backcross progeny and their individual genotypes for per and g were scored. The linkage analysis revealed that the photoperiodic clock gene (cpp) and per are localized separately on the X-chromosome.
日本昆虫学会の論文
1999-12-25