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基于体侧色斑、背鳍前部形态、吻长及尾柄长的差异,Ng和Kottelat(2007)将分布于中国的黄颡鱼群体划为两个物种:北方群体为Pseudobagrus sinensis,南方群体为P.fulvidraco。本研究通过对70个黄颡鱼标本相关形态特征的测量及对线粒体cyt b基因序列的分析,探讨了P.sinensis物种的有效性问题。结果表明:依据体侧色斑和背鳍前部形态的差异,可将黄颡鱼分为对应于P.sinensis和P.fulvidraco的两种形态类型,但对尾柄长、吻长的测量发现二者没有差异。对70条cyt b基因序列的分析结果为:两种鱼类有1个共同的单倍型;两种鱼类的单系性在系统发育分析中都没有得到重现,而二者聚在一起形成获得100%支持率的单系群;两种鱼类群体之间存在持续的基因交流(Nm=4.7);两种鱼类在单倍型的巢式支系分析(nested clade analysis,NCA)中没有形成各自独立的进化谱系,所有的单倍型以不超过5步的突变全部被纳入同一个进化网络中。因此我们认为P.sinensis不是有效物种,而应被视为黄颡鱼的一种形态类型。基于cyt b基因的序列变异,本研究对黄颡鱼群体的遗传多样性和种群结构作了初步分析。群体的核苷酸不配对分布及Tajima’s D中性检验表明,约在10.1-14.1万年前,黄颡鱼在其分布范围内经历过群体扩张,推测这可能是导致黄颡鱼群体单倍型多样度高(h=0.857±0.0014)而核苷酸多样度低(π=0.0023±0.0003)的主要原因。此外,分析结果显示黄颡鱼群体缺乏明显的地理结构,推测原因可能是历史上水系的连通促进了不同地理群体之间的基因交流。
Based on the difference between the plaque in the body, the anterior segment of the dorsal fin and the length of the tail and the length of the caudal peduncle, Ng and Kottelat (2007) classified the catfish population distributed in China as two species: the northern group Pseudobagrus sinensis, the southern group P.fulvidraco. In this study, we measured the related morphological characteristics of 70 specimens of the yellow croaker and analyzed the sequence of mitochondrial cyt b gene, and discussed the validity of P. sinensis species. The results showed that, according to the difference of the frontal dorsal fin and pigmentation, the yellow catfish could be divided into two morphological types corresponding to P.sinensis and P. fulvidraco. However, There is no difference. The analysis of the 70 cytb gene sequences showed that the two fish shared a common haplotype; the monophyleticity of both species did not reproduce in the phylogenetic analysis, and the two clustered together Forming a monophyletic group with 100% support; continuous gene exchange between the two fish groups (Nm = 4.7); two fish species in the haplotype nested clade analysis (NCA) Did not form their own independent evolutionary lineages, all haplotypes with no more than 5 mutations are all included in the same evolutionary network. Therefore, we think P.sinensis is not a valid species, but should be regarded as a morphological type of yellow catfish. Based on the sequence variation of cyt b gene, the genetic diversity and population structure of the catfish population were preliminarily analyzed. Population unpaired nucleotide distribution and Tajima’s D neutral test showed that about 10.1-14.1 million years ago, yellow catfish excreted within its distribution of population expansion, speculated that this may lead to yellow catfish haplotype The main reason for high diversity (h = 0.857 ± 0.0014) and low nucleotide diversity (π = 0.0023 ± 0.0003). In addition, the results of the analysis showed that there was a lack of a clear geographical structure in the catfish population, presumably due to the fact that historical water system connectivity facilitated gene exchange among different geographical groups.