The asymmetrical reproductive isolation of Drosophila albomicans and D. nasuta
Date Issued
2005
Date
2005
Author(s)
Tai, Yu-ta
DOI
zh-TW
Abstract
One of the most important issues in biology is: “How evolutionary process creates divergent groups known as species?” Drosophila albomicans (2n = 6) and D. nasuta (2n = 8) are sibling species with indistinguishable morphology but distinct karyotypes. Although these two species can easily produce viable and fertile hybrids in laboratory, no hybrids have ever been found in nature. Thus, we suggest that there may exist reproductive isolation between them. In this study, we focused on behavior isolation of premating mechanisms, and performed three kinds of mating choice experiments (i.e., multiple, female, and no choice). Size was ruled out as an important factor for mating success. The difference between no choice experiment and female choice revealed male-male interaction. If male-male interaction was excluded, what left is significant female choice of D. albomicans for conspecific males, but D. nasuta females mate randomly. This asymmetric female choice which fits Watanabe & Kawanishi’s hypothesis infers divergence of the ancestral population with gene flow. Due to strong lek behavior (i.e., stronger lunge) and the unique karyotype in D. albomicans male, we proposed that the neo-Y chromosome of D. albomicans may harbor more male specific genes to cause the difference. Clones of the male specific genes in these two species have been generated by suppressive subtractive hybridization. Further study is needed to verify this hypothesis.
Subjects
紅果蠅
輝顏果蠅
種化
雜合消去法
Drosophila albomicans
D. nasuta
speciation
suppressive subtractive hybridization
Type
thesis
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