在15,000年内,维多利亚湖单倍色胺的爆炸性适应性辐射,东非,产生了500种特有物种。在1980年代,尼罗河鲈鱼的热潮,人工引入湖中的食肉鱼,导致了200多只地方性丽鱼科动物的灭绝。尼罗河鲈鱼的捕食尤其受到伤害,包括恋童癖,丽鱼科动物吃鸡蛋和薯条,这是非洲丽鱼科鱼独特营养适应的一个例子。这里,旨在调查过去可能由尼罗河鲈鱼入侵引发的人口事件以及随后对丽鱼科鱼遗传结构的影响,我们进行了大规模比较基因组学。我们在四个物种中发现了最近瓶颈事件的证据,包括两个恋童癖,它始于1970-1980年代,人口规模在1990-2000年代反弹。瓶颈的时间对应于地方性单倍色胺消失和后来复活的历史记录,这可能与1950年代通过商业需求将尼罗河鲈鱼引入维多利亚湖有关。有趣的是,在可能经历瓶颈的四个物种中,单倍染色体。\'matumbi猎人,\'一只恋童癖丽鱼科鱼,显示了最严重的瓶颈签名。ADMIXTURE推断的共同祖先的组成部分表明,土木猎人与其他物种之间存在高度遗传差异。相比之下,我们的系统发育分析高度支持五种恋童癖的单体,与以前的研究结果一致。我们得出的结论是,由于最近的严重瓶颈导致维多利亚湖单倍色胺中共享遗传成分的丢失,导致了matumbihunter的高度遗传分化。
Within 15,000 years, the explosive adaptive radiation of haplochromine cichlids in Lake Victoria, East Africa, generated 500 endemic species. In the 1980s, the upsurge of Nile perch, a carnivorous fish artificially introduced to the lake, drove the extinction of more than 200 endemic cichlids. The Nile perch predation particularly harmed piscivorous cichlids, including paedophages, cichlids eat eggs and fries, which is an example of the unique trophic adaptation seen in African cichlids. Here, aiming to investigate past demographic events possibly triggered by the invasion of Nile perch and the subsequent impacts on the genetic structure of cichlids, we conducted large-scale comparative genomics. We discovered evidence of recent bottleneck events in 4 species, including 2 paedophages, which began during the 1970s to 1980s, and population size rebounded during the 1990s to 2000s. The timing of the bottleneck corresponded to the historical records of endemic haplochromines\" disappearance and later resurgence, which is likely associated with the introduction of Nile perch by commercial demand to Lake Victoria in the 1950s. Interestingly, among the 4 species that likely experienced bottleneck, Haplochromis sp. \"matumbi hunter,\" a paedophagous
cichlid, showed the most severe bottleneck signatures. The components of shared ancestry inferred by ADMIXTURE suggested a high genetic differentiation between matumbi hunter and other species. In contrast, our phylogenetic analyses highly supported the monophyly of the 5 paedophages, consistent with the results of previous studies. We conclude that high genetic differentiation of matumbi hunter occurred due to the loss of shared genetic components among haplochromines in Lake Victoria caused by the recent severe bottleneck.