华南长江和西江流域鲤科宽鳍鱲和马口鱼不同线粒体DNA谱系之间的体形分化

本文研究了两种鲤科鱼类,即分布于华南长江与西江的宽鳍鱲和马口鱼的不同线粒体DNA谱系之间的体形差异。近期基于线粒体DNA的这两个物种的系统发育分析认为这两个类元内包含多个谱系(宽鳍鱲A-D和马口鱼1-5)。本文采用几何形态度量学的方法研究了这些不同线粒体DNA谱系间是否存在体形方面的差异。在宽鳍鱲的4个不同的线粒体DNA谱系中,有3个被纳入本研究内容。结果显示:在宽鳍鱲的3个线粒体DNA谱系中,2个具有体形的差异。在马口鱼的5个线粒体DNA谱系中,3个被纳入本文的研究。结果显示所有3个谱系均存在体形差异。因此,线粒体DNA的谱系差异很大程度上表现在谱系间的体形差异方面,表明线粒体DNA谱系可能对应于不同的物种。

Body shape differentiation among mitochondrial-DNA lineages of Zacco platypus and Opsariichthys bidens ( Cyprinidae ) from the Changjiang and Xijiang river drainage areas in southern China

Recent advances in molecular methods have revealed many new lineages within taxa which formerly were seen as one distinct group(Avise,2000;Scotland et al.,2003).Some of these new lineages are described without data on the shape and morphology of the organism.Shape and morphology provide a lot of ecological information that might help to explain the diversification of new lineages(Schluter,2000)and the exclusion of shape and morphology subtracts important biological information.The cyprinids of Asia are a highly diversified group of freshwater fishes with more than 205 lineages(Rainboth,1991).Recent phylogeographic studies in this group have revealed that the current species taxonomy of several groups consists of a number of mitochondrial-DNA lineages,and that these lineages are mainly associated with geographical patterns of the drainage systems(Xiao et al.,2001;Perdices et al.,2004;Perdices et al.,2005).Perdices et al.(2004,2005)examined mitochondrial-DNA diversity of the cyprinids Zacco platypus and Opsariichthys bidens in drainages of the Changjiang(Yangtze)and Xijiang(Pearl)rivers in southern China,and found that the population structure in this area consisted of 4 and 5 lineages respectively.The authors suggested that the mitochondrial-DNA lineages of Zacco A-D and Opsariichthys 1-5 might correspond to different species.The purpose of this study is to examine if these mitochondrial-DNA lineages differ in body shape.I do this by analyzing body shape with geometric morphometrics(Rohlf and Marcus,1993).If the different mitochondrial-DNA lineages differ in body shape,this information will provide addition support to the suggestion that the lineages might correspond to different species(Perdices et al.,2004,2005).Analyzing the association of shape and genetic variation is beyond the scope of my study,and in addition such an analysis has many unresolved problems(Rohlf,2002).It should also be noted,that the aim of my study is not to describe new species.The aim is to examine whether the pattern demonstrated by the mitochondrial data is mirrored in shape differences among the lineages.