The genomic basis of adaptation to the deep water 'twilight zone' in Lake Malawi cichlid fishes
The genomic basis of adaptation to the deep water 'twilight zone' in Lake Malawi cichlid fishes
复制标题
马拉维湖丽鱼适应深水“暮光区”的基因组基础
DOI：
10.1101/102830
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Hahn C
中科院分区：
文献类型：
--
作者：
Hahn C
深水环境的特点是光谱越来越窄，可用光水平低，静水压力大，溶解氧减少--预计这些条件将施加高度特定的选择压力。在马拉维湖，800多种慈鱼已经进化，这种适应性辐射延伸到100米以下的“黄昏地带”。我们利用种群水平的RAD-SEQ数据来研究四种特有的深水物种(Diploaxodonspp.)在这种环境下经历了不同的选择。我们确定了候选基因，包括光感受器功能、光色素、晶状体形态和血红蛋白的调节，其中许多基因以前没有涉及到池鱼适应性辐射。功能相关基因的共同定位表明存在共同适应的“超基因”复合体。利用基因组重测序数据，将Diploaxod与更广泛的马拉维湖辐射进行比较，发现候选基因中存在功能替代。我们的数据为基因组对深海生活的适应提供了独特的见解，并表明基因组水平的深水栖息地专门化是慈济鱼辐射的一个重要过程。
Deep water environments are characterized by low levels of available light at increasingly narrow spectra, great hydrostatic pressure and reduced dissolved oxygen - conditions predicted to exert highly specific selection pressures. In Lake Malawi over 800 cichlid species have evolved, and this adaptive radiation extends into the “twilight zone” below 100 metres. We use population-level RAD-seq data to investigate whether four endemic deep water species (Diplotaxodonspp.) have experienced divergent selection within this environment. We identify candidate genes including regulators of photoreceptor function, photopigments, lens morphology and haemoglobin, many not previously implicated in cichlid adaptive radiations. Co-localization of functionally linked genes suggests co-adapted “supergene” complexes. Comparisons ofDiplotaxodonto the broader Lake Malawi radiation using genome resequencing data revealed functional substitutions in candidate genes. Our data provide unique insights into genomic adaptation to life at depth, and suggest genome-level specialisation for deep water habitat as an important process in cichlid radiation.