Reproductive skew in Japanese sardine inferred from DNA sequences
Reproductive skew in Japanese sardine inferred from DNA sequences
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DOI：
10.1093/icesjms/fsw070
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发表时间：
2016-09-01
影响因子：
3.3
通讯作者：
Yanagimoto, Takashi
中科院分区：
文献类型：
--
作者：
Niwa, Hiro-Sato;Nashida, Kazuya;Yanagimoto, Takashi
过多的低频突变是许多海洋物种普遍存在的特征，可以用三种假设来解释。首先，人口扩张假说假定许多物种在经历了更新世的种群瓶颈之后，经历了冰川后的扩张。第二种方法调用某种形式的自然选择，例如定向选择和选择性扫描。第三种解释是生殖偏斜假说，该假说认为许多海洋物种个体生殖成功率的高度变异会影响遗传多样性。在这项研究中，我们专注于人口学和繁殖成功，并使用合并理论来分析日本沙丁鱼的线粒体DNA序列。我们的结果表明，从两核苷酸差异的位置-频谱和错配分布估计的种群参数驳斥了人口扩张假说。此外，与生殖倾斜假说的预期相比，观察到的错配分布支持家谱中存在多个合并。在沙丁鱼家系中发现了许多短的外部分支，但很少有长的末端分支。模型的错误说明可能会导致对海洋物种遗传有效种群数量的当代和历史估计的误导性。海洋物种中生殖不对称的流行不仅影响遗传数据的分析，而且对理解被开发物种的生殖和招募模式的变化也具有生态学意义。
An excess of low-frequency mutations is a ubiquitous characteristic of many marine species, and may be explained by three hypotheses. First, the demographic expansion hypothesis postulates that many species experienced a post-glacial expansion following a Pleistocene population bottleneck. The second invokes some form of natural selection, such as directional selection and selective sweeps. The third explanation, the reproductive skew hypothesis, postulates that high variation in individual reproductive success in many marine species influences genetic diversity. In this study, we focused on demography and reproductive success and the use of coalescent theory to analyse mitochondrial DNA sequences from the Japanese sardine. Our results show that population parameters estimated from both the site-frequency spectrum and the mismatch distribution of pairwise nucleotide differences refute the demographic expansion hypothesis. Further, the observed mismatch distribution, compared with the expectations of the reproductive skew hypothesis, supports the presence of multiple mergers in the genealogy. Many short external branches but few long terminal branches are found in the sardine genealogy. Model misspecification can lead to misleading contemporary and historical estimates of the genetically effective population sizes in marine species. The prevalence of reproductive skew in marine species influences not only the analysis of genetic data but also has ecological implications for understanding variation in reproductive and recruitment patterns in exploited species.