Sawamura Kyoichi, Kamiya Koichi, Sato Hajime, Tomimura Yoshihiko, Matsuda Muneo, Oguma Yuzuru
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
Zoolog Sci. 2010 Apr;27(4):303-12. doi: 10.2108/zsj.27.303.
The Drosophila ananassae species cluster includes D. ananassae, D. pallidosa, D. parapallidosa, and the cryptic species "pallidosa-like", "pallidosa-like Wau" and "papuensis-like" Some of the taxa are sympatric in the South Pacific, Papua New Guinea, and Southeast Asia, and gene flow between different taxa has been suspected for a handful of genes. In the present analysis, we examined DNA sequences of introns in four loci: alpha actinin (Actn) on XL, white (w) on XR, CG7785 on 2L, and zinc ion transmembrane transporter 63C (ZnT63C) on 2R. Phylogenetic trees (neighbor-joining and haplotype network) were inconsistent among these loci. Some haplotypes shared between taxa were found for w, CG7785, and ZnT63C, suggesting recent gene flow. However, no haplotypes were shared, for example, between D. ananassae and D. pallidosa for CG7785, which is close to the proximal breakpoint of In(2L)D. This suggests that taxon-specific inversions prevent gene flow, as predicted by the chromosomal speciation hypothesis.
果蝇类群包括拟果蝇、苍白果蝇、类苍白果蝇以及隐存种“类苍白果蝇”、“瓦乌类苍白果蝇”和“类巴布亚果蝇”。其中一些分类单元在南太平洋、巴布亚新几内亚和东南亚同域分布，并且怀疑不同分类单元之间存在少数基因的基因流动。在本分析中，我们检测了四个位点内含子的DNA序列：X染色体左臂上的α辅肌动蛋白（Actn）、X染色体右臂上的白眼（w）、第二染色体左臂上的CG7785以及第二染色体右臂上的锌离子跨膜转运蛋白63C（ZnT63C）。这些位点之间的系统发育树（邻接法和单倍型网络）并不一致。在白眼、CG7785和ZnT63C中发现了一些分类单元之间共享的单倍型，这表明近期存在基因流动。然而，例如在CG7785位点，拟果蝇和苍白果蝇之间没有共享单倍型，该位点靠近In(2L)D的近端断点。这表明特定分类单元的倒位会阻止基因流动，正如染色体物种形成假说所预测的那样。
