云南红河水系李仙江麦穗鱼不同地理居群的形态分化

Morphological differentiation of Pseudorasbora parva among different geographical populations from Lixianjiang

摘要:

对采自李仙江流域江城、墨江和镇沅三个居群89尾麦穗鱼标本进行11个常规性状和16个框架结构性状的测量，应用多变量形态度量学结合主成分分析、判别分析和差异系数分析等3种方法比较李仙江3个地理居群间的形态差异。结果均支持镇沅居群较为独立。其中，主成分分析中PC1、PC2和PC3贡献率分别为55.094%，8.397%，6.988%，累积贡献率达70.469%，在PC1、PC2散点图中，镇沅居群个体基本独立分出。应用判别分析，从27个性状变量逐步筛选出对区分3个居群标本贡献较大的7个性状（P<0.01），建立麦穗鱼三个地理居群的判别函数式，发现对镇沅居群的判别率高达100%，对江城、墨江居群的判别率均为96.7%。同样取起主要贡献作用的7个性状与体长的比值进行形态差异系数分析，发现江城居群与镇沅居群之间差异系数大于1.28的性状有3个，墨江居群与镇沅居群之间亦有3个。镇沅居群产生形态变异，除可能受来源、生境因素影响外，遗传因素也发挥着不可忽视的作用。因此在后续研究中还需借助分子生物学手段进行分析。

Abstract:

In this study, 11 normal characters and 16 frame traits had been measured in 89 Pseudorasbora parva among different geographical populations (Zhenyuan, Mojiang and Jiangcheng) from Lixianjiang, Red River drainage. These data were analyzed by three different methods, the principal component analysis (PCA), the discriminant analysis and the coefficient of difference analysis to compare the morphological differences among the three geographical populations of P. parva. The results showed that Zhenyuan population was independent from the other populations. In PCA analysis, the contribution rates of PC1, PC2 and PC3 were 55.094%, 8.397%, and 6.988% respectively, and cumulatively to 70.469%. Furthermore, largely independent samples in Zhenyuan were separated in the scatter plot results by the PC1 and PC2. Also in the discriminant analysis, the discriminant rate based on 7 characters variable (P<0.01) reached 100% in Zhenyuan populations, while 96.7% both in Mojiang and Jiangcheng populations. Then, the same 7 traits with body length ratio were used for coefficient of difference analysis, and it was found that both with 3 characters with the more difference coefficient than 1.28 between Jiangcheng and Zhenyuan, Mojiang and Zhenyuan populations. It is speculated that there are morphological variations in Zhenyuan P. parva. Except the real source of the P. parva, environmental factors, genetic factors may also play a significant role in morphological variation. Therefore, it is necessary to study it by means of molecular biology in future.