A Single Gene Causes an Interspecific Difference in Pigmentation in Drosophila
A Single Gene Causes an Interspecific Difference in Pigmentation in Drosophila
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DOI：
10.1534/genetics.115.174920
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发表时间：
2015-05-01
期刊：
影响因子：
3.3
通讯作者：
Sweigart, Andrea L.
中科院分区：
文献类型：
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作者：
Ahmed-Braimah, Yasir H.;Sweigart, Andrea L.
物种差异的遗传基础仍然研究不足。对昆虫的研究极大地促进了我们对形态进化的理解。特别是色素性状受到了极大的关注，昆虫色素途径中的几个基因与种间和种内差异有关。尽管如此，仍然有很多未知的许多基因在这一途径和他们的潜在作用，在未充分研究的类群。在这里，我们从遗传学上分析了果蝇雄性组成员之间的蛹颜色差异。果蝇D. virilis的蛹期为黑色，而D. americana、美洲盾叶甲D. novamexicana和D.林眉是棕色的。本研究利用D. americana和D. virilis来绘制导致这一物种对之间差异的基因组间隔。首先，我们表明，蛹的情况下颜色差异是由一个单一的孟德尔化因子，我们最终映射到一个类似的11 kb的区域上的染色体5。映射的间隔仅包括多巴胺N-乙酰转移酶基因（Dat）的第一外显子和调控区。该基因编码一种已知在昆虫色素途径中起作用的酶。其次，我们发现该基因在浅棕色类群中化蛹开始时高度表达（D。americana和D. novamexicana）相对D. virilis，而不是在深棕色D. Lummei。最后，我们研究了Dat在D. americana（重度黑化）和D. novamexicana（轻度黑化），并发现该基因在成年人中没有明显的作用。我们的研究结果表明，一个单一的基因是完全或几乎完全负责物种之间的形态差异。
The genetic basis of species differences remains understudied. Studies in insects have contributed significantly to our understanding of morphological evolution. Pigmentation traits in particular have received a great deal of attention and several genes in the insect pigmentation pathway have been implicated in inter- and intraspecific differences. Nonetheless, much remains unknown about many of the genes in this pathway and their potential role in understudied taxa. Here we genetically analyze the puparium color difference between members of the virilis group of Drosophila. The puparium of Drosophila virilis is black, while those of D. americana, D. novamexicana, and D. lummei are brown. We used a series of backcross hybrid populations between D. americana and D. virilis to map the genomic interval responsible for the difference between this species pair. First, we show that the pupal case color difference is caused by a single Mendelizing factor, which we ultimately map to an similar to 11-kb region on chromosome 5. The mapped interval includes only the first exon and regulatory region(s) of the dopamine N-acetyltransferase gene (Dat). This gene encodes an enzyme that is known to play a part in the insect pigmentation pathway. Second, we show that this gene is highly expressed at the onset of pupation in light brown taxa (D. americana and D. novamexicana) relative to D. virilis, but not in the dark brown D. lummei. Finally, we examine the role of Dat in adult pigmentation between D. americana (heavily melanized) and D. novamexicana (lightly melanized) and find no discernible effect of this gene in adults. Our results demonstrate that a single gene is entirely or almost entirely responsible for a morphological difference between species.