Qigen Liu

Population structure and genetic diversity of Sinibrama macrops from Ou River and Ling River based on mtDNA D-loop region analysis, China.

Abstract In order to understand the influence of human activities such as habitat fragmentation on freshwater fish population evolution, we investigated and compared the genetic diversity and phylogeography of Sinibrama macrops populations in the Oujiang River and Ling River. Mitochondrial control region sequences (D-loop region) of 131 specimens from six populations were obtained and analyzed. The diversity of main stream in the Ou River was lower than that in Ling River. Changtan population showed the lowest diversity (H = 0.646 ± 0.077; π = 0.00060 ± 0.00820). Pairwise FST, gene flow (Nm), and genetic distance (Da) indicated that Longquan and Changtan significantly differentiate from other populations. Nested clade phylogeographical analysis (NCPA) showed some clades and total cladogram experienced isolation by distance. In conclusion, the populations from severely fragmented Ou River have the lower diversity and more intense differentiation than that from the mainstream of Ling River, Changtan population present the lowest diversity and were isolated by the dam construction.

Morphology and D-loop sequence analysis of Sinibrama macrops from Qiandaohu Lake

Morphological and genetic differences of three Sinibrama macrops populations from Qiandaohu Lake were compared by traditional morphological method and mitochondrial D-loop region sequence analysis.Based on the results of principal component analysis,specimens clustered together by scatter plots of scores could not be divided.It indicated that there is no morphological differentiation among all samples from Qiandaohu Lake.27 polymorphic sites were detected yielding 72 haplotypes.NJ tree and network showed that the geographic distribution was ambiguous.There were similar base composition among the three populations,and the content of A+T(64.82%)was higher than the content of G+C(35.18%).High genetic variation(h)and low nucleotide diversity(π)were found in the three populations analyzed for D-loop,and the diversity of Fenkou(h=0.968±0.018,π=0.004 76±0.000 49)was the highest,Linqi(h=0.968±0.017,π=0.004 53±0.000 41)was the second,Fuwen(h=0.937±0.037,π=0.003 30±0.000 35)was the lowest.The values of genetic differentiation index(Fst)were lower than 0.05 and not significant(P0.05).A strong gene flow among the populations was observed(Nm4),and the Nm between Fenkou and Fuwen was highest(Nm=27.40).The results showed that the three geographical populations belong to a randomly mating population.Consequently,we suggest keeping the pattern of gene flow of S.macrops,and reducing the influence of human activities so as to protect this important species in fishery resources.