title: DNA barcoding and evaluation of genetic diversity in Cyprinidae fish in the midstream of the Yangtze River.
abstract: The Yangtze River is the longest river in China and is divided into upstream and mid-downstream regions by the Three Gorges (the natural barriers of the Yangtze River), resulting in a complex distribution of fish. Dramatic changes to habitat environments may ultimately threaten fish survival; thus, it is necessary to evaluate the genetic diversity and propose protective measures. Species identification is the most significant task in many fields of biological research and in conservation efforts. DNA barcoding, which constitutes the analysis of a short fragment of the mitochondrial cytochrome c oxidase subunit I (COI) sequence, has been widely used for species identification. In this study, we collected 561 COI barcode sequences from 35 fish from the midstream of the Yangtze River. The intraspecific distances of all species were below 2% (with the exception of Acheilognathus macropterus and Hemibarbus maculatus). Nevertheless, all species could be unambiguously identified from the trees, barcoding gaps and taxonomic resolution ratio values. Furthermore, the COI barcode diversity was found to be low (≤0.5%), with the exception of H. maculatus (0.87%), A. macropterus (2.02%) and Saurogobio dabryi (0.82%). No or few shared haplotypes were detected between the upstream and downstream populations for ten species with overall nucleotide diversities greater than 0.00%, which indicated the likelihood of significant population genetic structuring. Our analyses indicated that DNA barcoding is an effective tool for the identification of cyprinidae fish in the midstream of the Yangtze River. It is vital that some protective measures be taken immediately because of the low COI barcode diversity.
authors.affiliation: The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 Hubei China; University of Chinese Academy of Sciences Beijing 100039 China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Shen
authors.affiliation: College of Life Science and Technology Xinxiang Medical University He'nan Xinxiang 453003 China.
authors.forename: Lihong
authors.initials: L
authors.lastname: Guan
authors.affiliation: The Key Laboratory of Freshwater Biodiversity Conservation Ministry of Agriculture Yangtze River Fisheries Research Institute Chinese Academy of Fishery Sciences Wuhan China.
authors.forename: Dengqiang
authors.initials: D
authors.lastname: Wang
authors.affiliation: The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 Hubei China.
authors.forename: Xiaoni
authors.initials: X
authors.lastname: Gan
keywords: Cyprinidae; DNA barcoding; Kimura's two‐parameter; cytochrome c oxidase subunit I; identification