Genomics of population differentiation in humpback dolphins, Sousa spp. in the Indo-Pacific Ocean

Speciation is a fundamental process in evolution and crucial to the formation of biodiversity. It is a continuous and complex process, which can involve multiple interacting barriers leading to heterogeneous genomic landscapes with various peaks of divergence among populations. In this study, we used a population genomics approach to gain insights on the speciation process and to understand the population structure within the genus Sousa across its distribution in the Indo-Pacifc region. We found 5 distinct clusters, corresponding to S. plumbea along the eastern African coast and the Arabian Sea, the Bangladesh population, S. chinensis off Thailand and S. sahulensis off Australian waters. We suggest that the high level of differentiation found, even across geographically close areas, is likely determined by different oceanographic features such as sea surface temperature and primary productivity.物种形成（speciation）是演化过程中的核心环节，对生物多样性的形成至关重要。该过程兼具连续性与复杂性，可涉及多种相互作用的生殖隔离屏障，进而形成群体间存在各异分化峰值的异质性基因组景观。本研究借助种群基因组学（population genomics）方法，深入解析物种形成过程，并厘清驼海豚属（Sousa）在印度洋-太平洋全域分布范围内的种群结构。本研究共鉴定出5个独立的聚类群，分别对应东非沿海与阿拉伯海的铅色驼海豚（S. plumbea）、孟加拉湾种群、泰国海域的中华白海豚（S. chinensis）以及澳大利亚海域的萨赫尔驼海豚（S. sahulensis）。本研究认为，即便在地理距离相近的区域，所观测到的高度遗传分化现象，大概率由海水表面温度、初级生产力等不同海洋学特征所决定。