Genome size, known also as the C-value, has been proposed as an important determinant of life-history variation in numerous animal taxa. We assessed the relationships between genome size and fitness-related life-history traits in six species of interstitial marine annelids of the genus Ophryotrocha. Life-history traits and genome size data obtained from 18 additional annelid species were included in our analyses to have a broader phylogenetic scope. Unexpectedly, genome sizes assessed here by flow cytometry in four Ophryotrocha species were three times larger than previously reported values obtained using Feulgen densitometry. This has implications for the hypothesis that harsh interstitial habitats select for small genomes in meiofaunal annelids. Within the genus Ophryotrocha, significant and positive relationships were found between genome size and nucleus size, and between genome size, age at first egg mass deposition, body size and lifespan. These relationships held up in the broader phylogenetic comparison. Our study provides evidence for the important role played by genome size in the evolution of life-history traits in annelids.

已经提出基因组大小，也称为C值，是许多动物类群中生活史变异的重要决定因素。我们评估了Ophryotrocha属的六种间质海洋类小动物的基因组大小与适应性相关的生活史特征之间的关系。从18种其他类动物获得的生活史特征和基因组大小数据也包括在我们的分析中，以具有更广阔的系统发育范围。出乎意料的是，此处通过流式细胞术评估的四种Otroyotrocha物种的基因组大小比以前使用Feulgen密度法获得的值大三倍。这为假说认为，严峻的间质生境选择了人参肛门的小基因组。属内Ophryotrocha在基因组大小和细胞核大小之间，以及基因组大小，第一次卵团沉积的年龄，体型和寿命之间存在显着正相关关系。这些关系在更广泛的系统发育比较中得到了证实。我们的研究提供了证据，证明了基因组大小在拟南芥生活史特征演变中的重要作用。