Endemic lake Baikal amphipods Raw sequence reads

Species flocks, large clades that have evolved from a common ancestor within a limited geographic range such as an ancient lake or isolated islands, provide splendid opportunities to study many aspects of evolution. Lake Baikal, which is at least 16 MY old and contains fully oxygenated depths of up to 1650m, harbors a unique fauna that includes several spectacular endemic species flocks (sponges, planarians, at least 3 groups of gastropods and, finally, amphipods). There are at least 250 described species of endemic Baikal amphipods that represent two independent invasions into Baikal. Baikal amphipods possess extreme morphological and ecological diversity. Morphologically, they include miniature and giant (up to 12cm) species, highly-armored, spiny species strikingly resembling unrelated marine forms and the unique planktonic amphipod Macrohectopus branickii. Ecologically, they range from typical generalist omnivorous/detritus-feeding species to highly specialized active predators, abyssal scavengers, plankton feeders, parasites or commensals of spongers and parasites of other amphipods. Thus, wide ecological diversification and high species richness make the adaptive radiation of Lake Baikal amphipods an excellent model system for adaptive research. Here we report transcriptomes of 64 species of lake Baikal amphipods.物种集群（species flock）是由共同祖先演化而来、且局限于特定地理范围（如古湖或孤岛）的大型演化支（clades），为研究进化的诸多维度提供了绝佳契机。贝加尔湖（Lake Baikal）距今至少1600万年，其最深达1650米的水体全程含氧，孕育了独特的动物区系，包含多个极具代表性的特有物种集群：海绵动物、涡虫、至少3类腹足类，以及端足类（amphipods）。目前已记述的贝加尔湖特有端足类至少有250种，它们源自两次独立的入侵贝加尔湖事件。贝加尔湖端足类展现出极强的形态与生态多样性。形态层面，其类群包含微型与巨型（最大体长可达12厘米）物种、高度装甲化且具棘刺的物种——其外形与非亲缘的海洋类群极为相似，还有独特的浮游端足类Macrohectopus branickii。生态层面，其生存策略与食性跨度极广：从典型的广食性杂食/碎屑食性物种，到高度特化的主动捕食者、深渊食腐者、浮游食性者、海绵共栖者，以及其他端足类的寄生者。因此，极高的生态多样性与物种丰富度，使得贝加尔湖端足类的适应性辐射成为适应性研究的极佳模型体系。本研究报道了64种贝加尔湖端足类的转录组（transcriptome）数据。