title: Historical Relationships among Wild Boar Populations of the Ryukyu Archipelago and Other Eurasian regions, as Inferred from Mitochondrial Cytochrome b Gene Sequences.
abstract: The Ryukyu wild boar (Sus scrofa riukiuanus) is an endemic, morphologically defined subspecies of the Eurasian wild boar (S. scrofa) found on five islands of the Ryukyu Archipelago (a group of small islands stretching from mainland Japan to Taiwan). Two hypothetical scenarios have been proposed regarding the origin of the current Ryukyu wild boar populations: 1) natural dispersal and 2) transportation and subsequent release by prehistoric humans. To test these two hypotheses, we compared the mitochondrial cytochrome b gene sequence (1140 base pairs) in 352 individual wild boar samples that included representatives of all five insular populations of the Ryukyu wild boar and populations of other conspecific subspecies in insular East and Southeast Asia and the Eurasian Continent. A total of 68 haplotypes were recognized, of which 12 were unique to the Ryukyu wild boar populations. The results of Bayesian phylogenetic analyses supported monophyly of the five Ryukyu populations (posterior probability value of 92), confirming the validity of the subspecies as a natural group. Coalescent analysis estimated the divergence times between the Ryukyu wild boar and the other conspecific subspecies as 144-465 thousand years ago (Kya), with a 95% HPD (highest posterior density) range of 51-837 Kya, and with no significant migration. Taking the broadly accepted date of initial human migration to the Ryukyus (no earlier than 50 Kya) into consideration, our results strongly suggest that the ancestral form of the Ryukyu wild boar first entered the Ryukyu Archipelago by natural dispersal prior to the arrival of prehistoric humans.
authors.affiliation: 1 School of Agriculture, Meiji University, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan.
authors.forename: Saka
authors.initials: S
authors.lastname: Yoshikawa
authors.affiliation: 2 School of Agriculture, Tamagawa University, Tamagawa-Gakuen, Machida, Tokyo 194-8610, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Mimura
authors.affiliation: 3 Iriomote Station, Tropical Biosphere Research Center, University of the Ryukyus, Uehara,Taketomi-cho, Yaeyama-gun, Okinawa 907-1541, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Watanabe
authors.affiliation: 4 Department of Life Science, Tunghai University, Taichung 407, Taiwan.
authors.forename: Liang-Kong
authors.initials: LK
authors.lastname: Lin
authors.affiliation: 5 Institute of National and Environmental Sciences, University of Hyogo,and Museum of Nature and Human Activities, Yayoigaoka 6,Sanda, Hyogo 669-1546, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Ota
authors.affiliation: 1 School of Agriculture, Meiji University, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Mizoguchi
mesh_terms: D063147:Animal Distribution; D000818:Animals; D045303:Cytochromes b / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D014644:Genetic Variation; D062312:Islands; D010802:Phylogeny; D058974:Phylogeography; D034421:Sus scrofa / Q000145:classification / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial; D045303:Cytochromes b
keywords: Ryukyu wild boar; coalescent analysis; divergence time; migration; phylogenetic analysis