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.
展开▼
机译:色素沉着是一个快速发展的特征,在许多生物中都受到自然和有性选择的影响。在果蝇的奎纳里亚(Quinaria)组中,几乎所有30种物种的腹部颜色浅,带有明显的标记。 D. tenebrosa是一个例外,因为它的腹部完全黑色,没有可见的痕迹。在这项研究中,我们使用定量遗传和候选基因方法的组合,以调查D.tenebrosa腹部色素沉着的遗传基础。我们发现腹部色素沉着在野生的D.tenebrosa系中是不变的,并且不是两性的。利用tenebrosa和浅色次生D.subccidentalis之间的杂交进行的定量遗传作图表明,两个基因组区域共同构成了腹部色素沉着,包括X染色体和常染色体(Muller Element C / E)。它们在色素沉着中的中心重要性的进一步支持是,一个表型在任一方向上向其他物种的基因渗入都会导致这两个基因组区域的渗入。最后,X连锁基因黄色在the中的表达正好预示了两个物种腹部的成年黑色化模式,这表明黄色调节的变化对于D. tenebrosa与其他物种的表型差异很重要。奎纳里亚集团。这些结果有助于证明一个高度保守的基因表达变化如何引起即使在密切相关的物种之间也存在实质性的表型差异的工作。
展开▼