| This paper include two aspects: First, mt DNA(Cyt b+D-loop) and nu DNA(rp S7+Rag2) were used to reconstruct the phylogenetic relationships of Microphysogobio species in southern mainland China to speculate the origination of Taiwan freshwater fishes; Second, mt DNA(Cyt b+D-loop) was used to analyze phylogeographic patterns and population genetic structure of 10 Microphysogobio labeoides populations and 4 Onychostoma lepturum populations. We further used nu DNA(Rag2+rp S7) to investigate the population structure and phylogeographic patterns of 10 M. labeoides populations in southern China. Furthermore, we used Cyt b to investigated the genetic diversity of Zacco platypus. The results were shown as follows: 1 Phylogenetic relationships of Microphysogobio species in Southern mainland China and TaiwanThis study analyzed the phylogenetic relationships of Microphysogobio reconstructed by mt DNA(Cyt b+D-loop) 、 nu DNA(rp S7+Rag2) 、 mt DNA(Cyt b+D-loop) and nu DNA(rp S7+Rag2). 163 mt DNA sequences with 1974 base pairs(1027bp Cyt b gene and 947 bp D-loop region); 114 nu DNA(rp S7+Rag2) sequences with 1358bp(729bp Rag2 and 629 bp rp S7 gene); 112 sequences with 3332 base pairs(1027bp Cyt b gene, 947 bp D-loop region, 729 bp Rag2 and 629 bp rp S7 gene). 1) The analysis of mt DNA: 163 individuals defined 109 haplotypes, the phylogenetic tree suggested that the Microphysogobio we sampled maybe divided into 15 species, pairwise distances among these groups are 0.031-0.173(mean=0.103). Microphysogobio brevirostris in northern Taiwan closed to one species in Zhemin area, Microphysogobio alticorpus in southern Taiwan closed to the species from Changjiang, Pearl and Qiantang River. 2) The analysis of nu DNA: 114 samples defined 93 haplotypes, the phylogenetic tree suggested that the Microphysogobio we sampled maybe divided into 12 groups, pairwise distances among these groups are 0.007-0.061(mean=0.033). M. brevirostris in northern Taiwan closed to one species in Zhemin area, M. alticorpus in southern Taiwan closed to the species from Changjiang River. 3) The analysis of mt DNA+nu DNA: the phylogenetic tree suggested that the Microphysogobio we sampled maybe divided into 14 groups(Microphysogobio tafangensis, Microphysogobio yaluensis, Microphysogobio labeoides, Microphysogobio fukiensis, Microphysogobio elongatus, Microphysogobio brevirostris, Microphysogobio alticorpus and M. sp1-7), pairwise distances among these groups are 0.020-0.108(mean=0.069). M. brevirostris in northern Taiwan closed to one species in Zhemin area, M. alticorpus in southern Taiwan closed to the species from Changjiang. The results of S-DIVA suggested that the ancestral haplotype of M. brevirostris distriuted in Zhemin area, while the ancestral haplotype of M. alticorpus distributed in Changjiang, Qiangtang and Pearl River. The genetic variations among M. alticorpus and other species are really high, so we infered there may be some species we had did not sampled. From these we speculated that M. alticorpus in southern Taiwan maybe dispersed from Changjiang and Pearl River; species in northern Taiwan is dispersed from Zhemin area. The analysis of mt DNA and nu DNA revealed that the species diversity may be underestimated in Microphysogobio. 2 Phylogeography of Microphysogobio labeoides and Onychostoma lepturum.Phylogeographic patterns and population genetics of M. labeoides and O. lepturum were investigated based on mt DNA sequences. 1) Genetic diversity: As for M. labeoides, 211 mt DNA sequences with 1974bp(1027bp Cyt b and 947 bp D-loop) defined 67 haplotypes, including 123 variable sites(6.23%), 93 parsimoniously informative sites(4.71%). The average haplotype diversity is 0.9680 and the average nucleotide diversity is 0.016353. For O. lepturum 63 mt DNA sequences with 1748bp(1064bp Cyt b and 674 bp D-loop gene) fall into 31 haplotypes, including 268 variable sites(15.33%), 110 parsimoniously informative sites(6.29%). The average haplotype diversity is 0.9421 and the average nucleotide diversity is 0.023896. 2) Phylogenetic relationship: ML haplotype tree showed that the 9 drainages of M. labeoides can be divided into 7 lineages, Jiulong River(HA), Dongjiang(HY) and Rongjiang(JYRJ) claded in one lineage and the others divided into 6 lineages respectively. And the HH population claded with Hainan populations. The 4 populations of O. lepturum in Hainan Island is divided into 4 lineages. Both of the two species have significantly divergenced. 3) Genetic differentiation and genetic structure among populations: The FST values among populations of M. labeoides were from 0.73260 to 0.97301 and of O. lepturum were from 0.495 to 0.963. AMOVA and SAMOVA revealed that both of the two species have strong phylogeographic structure due to restricted gene flow among geographic populations. WY region in Hainan Island, Beibu wan, Qiongzhou strait, Lianhua mountains and Yunwu mountains are geographic barriers of M. labeoides, WY region is also the geographic barrier for O. lepturum. 4) Demographic History: Neutral test and mismatch analysis revealed that these two species had experienced a population expansion.We further used nu DNA(Rag2+D-loop) to investigate the population genetic of M. labeoides in southern China. 1) Genetic diversity: 115 mt DNA sequences with 1413bp(729bp Rag2 and 684 bp rp S7 gene), fall into 48 haplotypes, including 43 variable sites(3.04%), 28 parsimoniously informative sites(1.98%). There are some insertions in rp S7(6-11bp). The average haplotype and nucleotide diversity are 0. 937 and 0.011304 respectively. 2) Phylogenetic analysis: There is no obvious differentiation among 9 geographic populations of M. labeoides because the slower substitution rate of nuclear genes, this also supported by the network. 3) Genetic structure and differentiation among populations: The FST values among populations of M. labeoides were from-0.07692 to 1.00000, the FST values between HA and HY, JYRJ and LH less than 0. AMOVA and SAMOVA revealed that this species have strong phylogeographic structure due to restricted gene flow among geographic populations. WY region in Hainan Island, Beibu wan, Qiongzhou strait, Lianhua mountains and Yunwu mountains are geographic barriers of M. labeoides. 4) Demographic History: Neutral test and mismatch analysis revealed that this species had not experienced a population expansion.We divided Z. platypus in southern China into 10 matrilines, with relatively high molecular divergence found among them. The Huangshan population had the greatest genetic variation among all sampled regions and hosted six of the ten matrilines. Our results highlight the significance of the Huangshan area for the conservation of Zacco platypus. |
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