Data from: Determination of the genetic architecture underlying short wavelength sensitivity in Lake Malawi cichlids

African cichlids are an exemplary system to study organismal diversity and rapid speciation. Species differ in external morphology including jaw shape and body coloration, but also differ in sensory systems including vision. All cichlids have 7 cone opsin genes with species differing broadly in which opsins are expressed. The differential opsin expression results in closely related species with substantial differences in spectral sensitivity of their photoreceptors. In this work, we take a first step in determining the genetic basis of opsin expression in cichlids. Using a second generation cross between 2 species with different opsin expression patterns, we make a conservative estimate that short wavelength opsin expression is regulated by a few loci. Genetic mapping in 96 F2 hybrids provides clear evidence of a cis-regulatory region for SWS1 opsin that explains 34% of the variation in expression between the 2 species. Additionally, in situ hybridization has shown that SWS1 and SWS2B opsins are coexpressed in individual single cones in the retinas of F2 progeny. Results from this work will contribute to a better understanding of the genetic architecture underlying opsin expression. This knowledge will help answer long-standing questions about the evolutionary processes fundamental to opsin expression variation and how this contributes to adaptive cichlid divergence.

非洲慈鲷（African cichlids）是研究生物多样性与快速物种形成的典范实验体系。该类群不同物种不仅在颌骨形态、体色等外部形态上存在差异，在包括视觉在内的感官系统方面亦有所不同。所有慈鲷均拥有7个视锥视蛋白（cone opsin）基因，不同物种所表达的视蛋白（opsin）种类差异显著。视蛋白表达的差异使得亲缘关系较近的物种，其光感受器的光谱敏感性存在显著差异。本研究为解析慈鲷视蛋白表达的遗传基础迈出了第一步。我们利用两种视蛋白表达模式不同的慈鲷物种构建二代杂交群体，经保守估算，短波长视蛋白的表达受少数基因座调控。对96株F₂杂交个体的遗传定位分析，为SWS1视蛋白的顺式调控区域（cis-regulatory region）提供了明确证据，该区域可解释两个物种间34%的表达差异。此外，原位杂交（in situ hybridization）实验结果显示，F₂后代视网膜的单个单锥细胞中，SWS1与SWS2B视蛋白共表达。本研究结果有助于更深入地解析视蛋白表达背后的遗传调控架构。这些研究成果将有助于解答长期存在的科学问题：即视蛋白表达差异背后的核心进化过程，以及该差异如何推动慈鲷的适应性分化。