The question of whether spatial aspects of evolution differ in marine versus terrestrial realms has endured since Ernst Mayr's 1954 essay on marine speciation. Marine systems are often suggested to support larger and more highly connected populations, but quantitative comparisons with terrestrial systems have been lacking. Here, we compared the population histories of marine and terrestrial elapid snakes using the pairwise sequentially Markovian coalescent (PSMC) model to track historical fluctuations in species’ effective population sizes (N_e) from individual whole‐genome sequences. To do this we generated a draft genome for the olive sea snake (Aiysurus laevis) and analysed this alongside six published elapid genomes and their sequence reads (marine species Hydrophis curtus, H. melanocephalus and Laticauda laticaudata; terrestrial species Pseudonaja textilis, Naja Naja and Notechis scutatus). Counter to the expectation that marine species should show higher overall N_e and less pronounced fluctuations in N_e, our analyses reveal demographic patterns that are highly variable among species and do not clearly correspond to major ecological divisions. At deeper time intervals, the four marine elapids appear to have experienced relatively stable N_e , while each terrestrial species shows a prominent upturn in N_e starting at ~4 million years ago (Ma) followed by an equally strong decline. However, over the last million years, all seven species show strong and divergent fluctuations. Estimates of N_e in the most recent intervals (~10 kya) are lowest in two of four marine species (H. melanocephalus and Laticauda), and do not correspond to contemporary range sizes in marine or terrestrial taxa.

中文翻译：

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使用全基因组序列对海洋和陆地蛇（E科）进行人口统计分析

自从恩斯特·梅尔（Ernst Mayr）在1954年发表有关海洋物种形成的论文以来，就一直存在着关于海洋和陆地领域进化的空间方面是否不同的问题。人们通常建议海洋系统支持更大和更紧密联系的人口，但缺乏与陆地系统的定量比较。在这里，我们使用成对的顺序马尔可夫聚结（PSMC）模型比较了海洋和陆地椭圆形蛇的种群历史，以追踪各个完整基因组序列中物种有效种群大小（N _e）的历史波动。为此，我们生成了橄榄海蛇（Aiysurus laevis）的基因组草图，并与六个已发表的弹性基因组及其序列读数（海洋物种）一起进行了分析。湿，H. melanocephalus和Laticauda laticaudata ; 陆生物种Pseudonaja textilis，眼镜蛇眼镜蛇和Notechis scutatus）。计数器的期望，海洋物种应该表现出较高的综合ñ _é和不太明显的波动ñ _é，我们的分析表明人口结构是物种间变化很大，没有明确对应于重大生态区划。在更深的时间间隔内，四个海象似乎经历了相对稳定的N _e，而每个陆生物种在N _e上都呈现出明显的上升趋势。从大约400万年前（马）开始，然后同样强劲地下降。然而，在过去的一百万年中，所有七个物种均表现出强烈而分散的波动。在四个海洋物种（H. melanocephalus和Laticauda）中，有两个海洋物种（最近的间隔）的N _e估计值最低（约10 kya ），并且与现代海洋或陆地生物分类范围的大小不符。