Flow Cytometry Data from Genome size variation in deep-sea amphipods.

Genome size varies considerably across taxa, and extensive research effort has gone into understanding whether variation can be explained by differences in key ecological and life-history traits among species. The extreme environmental conditions that characterize the deep sea have been hypothesized to promote large genome sizes in eukaryotes. Here we test this supposition by examining genome sizes among 13 species of deep-sea amphipods from the Mariana, Kermadec and New Hebrides trenches. Genome sizes were estimated using flow cytometry and found to vary nine-fold, ranging from 4.06 pg (4.04 Gb) in <i>Paralicella caperesca</i> to 34.79 pg (34.02 Gb) in <i>Alicella gigantea</i>. Phylogenetic independent contrast analysis identified a relationship between genome size and maximum body size, though this was largely driven by those species that display size gigantism. There was a distinct shift in the genome size trait diversification rate in the supergiant amphipod <i>A. gigantea</i> relative to the rest of the group. The variation in genome size observed is striking and argues against genome size being driven by a common evolutionary history, ecological niche and life-history strategy in deep-sea amphipods.

不同分类群（taxa）的基因组大小（genome size）差异显著，学界已投入大量研究精力，试图探明物种间关键生态与生活史性状的差异能否解释基因组大小的变异。有假说认为，深海特有的极端环境条件会促使真核生物（eukaryotes）的基因组变大。本研究通过分析来自马里亚纳海沟、克马德克海沟以及新赫布里底海沟的13种深海端足类（amphipods）的基因组大小，对该假说进行了验证。研究采用流式细胞术（flow cytometry）估算基因组大小，结果显示其变异幅度达9倍，范围从<i>Paralicella caperesca</i>的4.06皮克（4.04 Gb）至<i>Alicella gigantea</i>的34.79皮克（34.02 Gb）。系统发育独立对比分析（phylogenetic independent contrast analysis）结果显示，基因组大小与最大体长存在关联，但该关联主要由表现出体型巨型化（size gigantism）的物种所驱动。相较于类群内其他物种，超巨型端足类<i>A. gigantea</i>的基因组大小性状分化速率发生了显著改变。本次观测到的基因组大小变异十分显著，这表明深海端足类的基因组大小并非由共同的演化历史、生态位以及生活史策略所决定。