Two genomic regions together cause dark abdominal pigmentation in Drosophila tenebrosa
Two genomic regions together cause dark abdominal pigmentation in Drosophila tenebrosa
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DOI：
10.1038/hdy.2013.124
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发表时间：
2014-04-01
期刊：
影响因子：
3.8
通讯作者：
Dyer, K. A.
中科院分区：
文献类型：
--
作者：
Bray, M. J.;Werner, T.;Dyer, K. A.
色素沉着是一种快速进化的特征，在许多生物体中都存在于自然选择和性选择之下。在果蝇的Quinaria类群中，几乎所有30种物种的腹部都是浅色的，有明显的斑点；细叶果蝇是个例外，它的腹部完全是黑色的，没有明显的斑点。在这项研究中，我们使用数量遗传和候选基因相结合的方法来研究细纹夜蛾腹部色素沉着的遗传基础。我们发现，腹部的色素沉着是不变的，在野外捕获的线虫，而不是性别二型性。利用黑刺粉虱与浅色粉虱杂交进行的定量遗传作图表明，腹部色素沉着有两个基因组区域，包括X染色体和常染色体(Muller元件C/E)。进一步支持它们在着色中的中心重要性的是，实验中一种表型向另一种物种的导入，无论是向哪个方向，都会导致这两个基因组区域的导入。最后，X连锁基因黄色在蛹中的表达恰好预示了两种昆虫腹部的成虫黑化模式，这表明黄色调节的变化对于细纹夜蛾与Quinaria组的其他成员的表型分化是重要的。这些结果有助于证明高度保守基因表达的变化如何导致即使在密切相关的物种之间也会产生实质性的表型差异。
Pigmentation is a rapidly evolving trait that is under both natural and sexual selection in many organisms. In the quinaria group of Drosophila, nearly all of the 30 species have an abdomen that is light in color with distinct markings; D. tenebrosa is the exception in that it has a completely melanic abdomen with no visible markings. In this study, we use a combination of quantitative genetic and candidate gene approaches to investigate the genetic basis of abdominal pigmentation in D. tenebrosa. We find that abdominal pigmentation is invariant across wild-caught lines of D. tenebrosa and is not sexually dimorphic. Quantitative genetic mapping utilizing crosses between D. tenebrosa and the light-colored D. suboccidentalis indicates that two genomic regions together underlie abdominal pigmentation, including the X-chromosome and an autosome (Muller Element C/E). Further support for their central importance in pigmentation is that experimental introgression of one phenotype into the other species, in either direction, results in introgression of these two genomic regions. Finally, the expression of the X-linked gene yellow in the pupae exactly foreshadows the adult melanization pattern in the abdomen of both species, suggesting that changes in the regulation of yellow are important for the phenotypic divergence of D. tenebrosa from the rest of the quinaria group. These results contribute to a body of work that demonstrates how changes in expression of highly conserved genes can cause substantial phenotypic differences even between closely related species.