Morse Peter, Kjeldsen Shannon R, Meekan Mark G, Mccormick Mark I, Finn Julian K, Huffard Christine L, Zenger Kyall R
Australian Institute of Marine Science UWA Oceans Institute Crawley WA Australia.
College of Science and Engineering James Cook University Townsville Qld Australia.
Ecol Evol. 2018 Jan 25;8(4):2253-2267. doi: 10.1002/ece3.3845. eCollection 2018 Feb.
The southern blue-ringed octopus, (Hoyle, 1883) lacks a planktonic dispersal phase, yet ranges across Australia's southern coastline. This species' brief and holobenthic life history suggests gene flow might be limited, leaving distant populations prone to strong genetic divergence. This study used 17,523 genome-wide SNP loci to investigate genetic structuring and local adaptation patterns of among eight sampling sites along its reported range. Within sites, interrelatedness was very high, consistent with the limited dispersal of this taxon. However, inbreeding coefficients were proportionally lower among sites where substructuring was not detected, suggesting might possess a mechanism for inbreeding avoidance. Genetic divergence was extremely high among all sites, with the greatest divergence observed between both ends of the distribution, Fremantle, WA, and Stanley, TAS. Genetic distances closely followed an isolation by geographic distance pattern. Outlier analyses revealed distinct selection signatures at all sites, with the strongest divergence reported between Fremantle and the other Western Australian sites. Phylogenetic reconstructions using the described sister taxon (Hoyle, 1886) further supported that the genetic divergence between distal H. maculosa sites in this study was equivalent to that of between established heterospecifics within this genus. However, it is advocated that taxonomic delineations within this species should be made with caution. These data indicate that forms a clinal species pattern across its geographic range, with gene flow present through allele sharing between adjacent populations. Morphological investigations are recommended for a robust resolution of the taxonomic identity and ecotype boundaries of this species.
南蓝环章鱼（Hoyle，1883）没有浮游扩散阶段，但分布于澳大利亚南部海岸线。该物种短暂的全底栖生活史表明基因流动可能有限，使得远距离种群容易出现强烈的遗传分化。本研究使用17523个全基因组SNP位点，调查了沿其报道分布范围内八个采样点的遗传结构和局部适应模式。在各采样点内，亲缘关系非常高，这与该分类群的有限扩散一致。然而，在未检测到亚结构的采样点中，近亲繁殖系数相对较低，这表明南蓝环章鱼可能拥有一种避免近亲繁殖的机制。所有采样点之间的遗传分化极高，在分布两端的西澳大利亚州弗里曼特尔和塔斯马尼亚州斯坦利之间观察到最大的分化。遗传距离紧密遵循地理距离隔离模式。异常值分析揭示了所有采样点的明显选择特征，弗里曼特尔与其他西澳大利亚州采样点之间的分化最为强烈。使用描述的姊妹分类群（Hoyle，1886）进行的系统发育重建进一步支持了本研究中黄斑章鱼远距离采样点之间的遗传分化等同于该属内已确定的异种之间的遗传分化。然而，有人主张对该物种内的分类划分应谨慎进行。这些数据表明，南蓝环章鱼在其地理范围内形成了一个渐变物种模式，通过相邻种群之间的等位基因共享存在基因流动。建议进行形态学研究，以有力地解决该物种的分类身份和生态型边界问题。
