Genetic analysis of reproductive isolation between Drosophila melanogaster and D. simulans
Date Issued
2014
Date
2014
Author(s)
Lin, Jui-Han
Abstract
Hybrid incompatibility (HI) and behavioral isolation in the forms of hybrid lethality or sterility are important barriers to prevent gene flow among species that may encounter each other, causing reproductive isolation and thus lead to speciation. The closely related Drosophila species, D. melanogaster and D. simulans, rarely mate each in nature despite diverging 2-3 million years ago. The cross between D. melanogaster females and D. simulans males produces sterile F1 females and males died at larval stage. The reciprocal cross yields sterile F1 males and embryonic lethal females. Using attached-X chromosome strains, it is proposed that the hybrid female lethality is caused by the presence of D. melanogaster X chromosome (Xm) and maternal product from D. simulans. To identify loci which contribute to the hybrid lethality, I conducted a genetic screen by crossing D. simulans females to males of the D. melanogaster X chromosome duplication lines that contain an extra X fragment on Y chromosomes in Zhr background. I have screened 22 lines covering 97.22 % of the X chromosome, and the results show that three of the 22 duplications have significant effect on hybrid male lethality. My results indicated that there are at least three regions on the Xm chromosome contributing to HI between D. melanogaster and D. simulans. To identify the genes responsible for the behavioral isolation between these sibling species, I used EMS mutagenesis to mutagenize D. melanogaster males to identify genes affecting male behaviors responsive to the acceptance by D. simulans females. The results indicated that the mutant lines we chose spending more time courtship heterospecific females.
Subjects
行為隔離
雜交不親合
果蠅
求偶行為
EMS突變
交配偏好
基因重複
Type
thesis
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