Drosophila pigmentation evolution:: Divergent genotypes underlying convergent phenotypes
Drosophila pigmentation evolution:: Divergent genotypes underlying convergent phenotypes
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DOI：
10.1073/pnas.0336368100
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发表时间：
2003-02-18
影响因子：
11.1
通讯作者：
Carroll, SB
中科院分区：
文献类型：
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作者：
Wittkopp, PJ;Williams, BL;Carroll, SB
类似的表型变化在许多动物分类群中独立进化。目前尚不清楚独立的变化是否涉及相同或不同的发育和遗传机制。果蝇属中无数的色素模式为解决这个问题提供了许多机会。先前的研究确定了在选定物种中参与色素沉着发育和多样化的调节和结构基因。本研究以美洲果蝇和新墨西哥果蝇为研究对象，这两种可育物种自分化以来，在数百万年的时间里进化出了显著的色素沉着差异。采用种间遗传分析方法，通过检测分子标记与色素沉着之间的关联，研究了5个特定候选基因和其他基因组区域对表型差异的贡献。至少有四个不同的基因组区域导致了色素沉着的差异，其中一个包括乌木基因。黑檀木蛋白在颜色较黄的新美洲龙骨中的表达水平高于黑化程度较重的美洲龙骨。由于乌木促进黄色色素形成并抑制黑化，因此表达差异和遗传关联表明，乌木焦点的进化促成了美洲黑檀和新美洲黑檀色素沉着的差异。令人惊讶的是，在本研究中没有检测到与黄色位点的遗传关联，并且黄色在两个物种中的表达是相同的。黄色焦点的进化是其他果蝇物种色素沉着差异的基础；因此，相似的色素模式通过不同谱系中不同基因的调控变化而进化。这些发现有助于理解黑变和模仿的经典模型。
Similar phenotypic changes have evolved independently in many animal taxa. It is unknown whether independent changes involve the same or different developmental and genetic mechanisms. Myriad pigment patterns in the genus Drosophila offer numerous opportunities to address this question. Previous studies identified regulatory and structural genes involved in the development and diversification of pigmentation in selected species. Here, we examine Drosophila americana and Drosophila novamexicana, inter-fertile species that have evolved dramatic pigmentation differences during the few million years since their divergence, Interspecific genetic analysis was used to investigate the contribution of five specific candidate genes and other genomic regions to phenotypic divergence by testing for associations between molecular markers and pigmentation. At least four distinct genomic regions contributed to pigmentation differences, one of which included the ebony gene. Ebony protein was expressed at higher levels in the more yellow D. novamexicana than the heavily melanized D. americana. Because Ebony promotes yellow pigment formation and suppresses melanization, the expression difference and genetic association suggest that evolution at the ebony focus contributed to pigmentation divergence between D. americana and D. novamexicana. Surprisingly, no genetic association with the yellow locus was detected in this study, and Yellow expression was identical in the two species. Evolution at the yellow focus underlies pigmentation divergence among other Drosophila species; thus, similar pigment patterns have evolved through regulatory changes in different genes in different lineages. These findings bear upon understanding classic models of melanism and mimicry.