Nofrianto Andy B, Lawelle Sjamsu A, Mokodongan Daniel F, Masengi Kawilarang W A, Inomata Nobuyuki, Hashiguchi Yasuyuki, Kitano Jun, Sumarto Bayu K A, Kakioka Ryo, Yamahira Kazunori
Faculty of Fisheries and Marine Science, Halu Oleo University, Kendari 93232, Indonesia.
Museum Zoologicum Bogoriense, Research Center for Biology, National Research and Innovation Agency, Cibinong 16911, Indonesia.
Zoolog Sci. 2022 Oct;39(5):453-458. doi: 10.2108/zs220023.
Freshwater halfbeaks of the genus (Zenarchopteridae) uniquely diversified on Sulawesi Island, where tectonic movements have been very active since the Pliocene. Most species of this genus have quite limited distributions, which indicates that geographic isolations have contributed to their diversification. In this study, we demonstrated that secondary contacts and resultant admixtures between long-isolated species/populations may have also been important. We found that the mitochondrial phylogeny of a group of in Southeast Sulawesi was discordant with the nuclear phylogeny. Most notably, individuals in the upper and lower streams of the Moramo River, a small river in this region, clustered with each other in the mitochondrial phylogeny but not in the nuclear phylogeny; in the latter, the lower-stream individuals formed a clade with individuals in the Anduna River, a different river with no present water connection to the Moramo River. Phylogenetic network and population structure analyses using genomic data obtained from RNA-seq revealed that the lower-stream Moramo population admixed with the upper-stream Moramo lineage in ancient times. These findings indicate that the observed mito-nuclear discordance was caused by mitochondrial introgression and not incomplete lineage sorting. The phylogenetic network also revealed several other admixtures between ancient lineages. Repeated admixtures were also evidenced by topological incongruence in population trees estimated using the RNA-seq data. We propose that activities of many fault systems dissecting Southeast Sulawesi caused repeated secondary contact.
（泽氏颌针鱼科）的淡水颌针鱼在苏拉威西岛独特地多样化发展，自上新世以来该岛的构造运动一直非常活跃。该属的大多数物种分布范围相当有限，这表明地理隔离促成了它们的多样化。在本研究中，我们证明长期隔离的物种/种群之间的二次接触以及由此产生的混合可能也很重要。我们发现，苏拉威西岛东南部一组[具体物种未给出]的线粒体系统发育与核系统发育不一致。最值得注意的是，该地区一条小河——莫拉莫河上下游的个体在线粒体系统发育中相互聚类，但在核系统发育中并非如此；在核系统发育中，下游个体与安杜纳河的个体形成一个分支，安杜纳河是一条与莫拉莫河目前没有水系连接的不同河流。使用从RNA测序获得的基因组数据进行的系统发育网络和种群结构分析表明，古代莫拉莫河下游种群与上游莫拉莫河谱系混合。这些发现表明，观察到的线粒体-核不一致是由线粒体基因渗入而非不完全谱系分选造成的。系统发育网络还揭示了古代谱系之间的其他几种混合情况。使用RNA测序数据估计的种群树中的拓扑不一致也证明了反复的混合情况。我们提出，切割苏拉威西岛东南部的许多断层系统的活动导致了反复的二次接触。
