| Autor: |
Nofrianto AB; Faculty of Fisheries and Marine Science, Halu Oleo University, Kendari 93232, Indonesia., Lawelle SA; Faculty of Fisheries and Marine Science, Halu Oleo University, Kendari 93232, Indonesia., Mokodongan DF; 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., Masengi KWA; Faculty of Fisheries and Marine Science, Sam Ratulangi University, Manado 95115, Indonesia., Inomata N; Department of Environmental Science, Fukuoka Women's University, Fukuoka 813-8529, Japan., Hashiguchi Y; Department of Biology, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan., Kitano J; Ecological Genetics Laboratory, National Institute of Genetics, Mishima, Japan., Sumarto BKA; Tropical Biosphere Research Center, University of the Ryukyus, Okinawa 903-0213, Japan., Kakioka R; Tropical Biosphere Research Center, University of the Ryukyus, Okinawa 903-0213, Japan., Yamahira K; Tropical Biosphere Research Center, University of the Ryukyus, Okinawa 903-0213, Japan, yamahira@lab.u-ryukyu.ac.jp. |
| Abstrakt: |
Freshwater halfbeaks of the genus Nomorhamphus (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 Nomorhamphus 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. |
