Post-Pleistocene demographic history of the North Atlantic endemic Irish moss Chondrus crispus: glacial survival, spatial expansion and gene flow

Range expansions and gene flow as micro-evolutionary processes played a leading role in the population demographic history of marine organisms. Herein, we sequenced partial mtDNA Cox1 gene from 26 assigned geographic populations in order to understand how Irish moss (Chondrus crispus) responded to severe climatic oscillations during the Pleistocene glaciations and contemporary forces such as gene flow. Phylogeographic patterns indicated that haplotype frequency distributions were strongly skewed, with nearly half found only in single samples and thus restricted to a single population. Analysis of molecular variance revealed that most of the variation was within populations with no significant genetic structuring on either side of the Atlantic. Demographic analyses indicated that ISI (Irish Sea and Ireland) and NS (the North Sea) areas experienced a slight trend of increase in population size over time, whereas EC (the English Channel) area experienced expansion beginning approximately ...

种群扩张与基因流作为微进化过程，在海洋生物的种群动态历史中发挥着主导作用。本研究对26个划定地理种群的线粒体DNA细胞色素c氧化酶亚基1（mtDNA Cox1）基因片段进行测序，以解析爱尔兰苔藓（*Chondrus crispus*）对更新世冰期剧烈气候波动及基因流等现代演化驱动力的响应机制。系统地理格局分析结果显示，单倍型频率分布呈现极强的偏态性，近半数单倍型仅在单个样本中检出，且仅局限于单一种群。分子方差分析（Analysis of Molecular Variance）结果表明，绝大多数遗传变异存在于种群内部，大西洋两岸均未出现显著的遗传结构分化。种群动态分析显示，ISI（爱尔兰海与爱尔兰区域）及NS（北海区域）的种群规模随时间推移呈微弱增长趋势，而EC（英吉利海峡区域）的种群规模约于……开始扩张。