中国二化螟不同地理种群的AFLP遗传分析

Genetic diversity of different geographical populations of Chilo suppressalis in China as determined by AFLP

利用AFLP标记对中国11省13个二化螟Chilo suppressalis(Walker)地理种群进行遗传多态性分析,以揭示不同区域种群间遗传分化,为建立较准确的二化螟发生区划及区域治理对策提供新的依据。选取3对引物,共扩增出445个位点,其中多态性位点数为386,多态性比率为86.8%。种群间分化系数(Gst)为0.74,基因流仅为0.176;13个地理种群间遗传一致度较高,均大于0.67。遗传距离聚类分析表明,二化螟13个地理种群可区分为4类,其中淮北平原类(赣榆、阜宁、阜南)、东南山区类(鄞县、闽侯)、荆湘川类(荆州、邵阳、德阳)三类种群分别具有较一致的地理气候特征或相对较近的距离。研究还表明,与其他测试种群的遗传距离普遍较大、相对孤立的地理种群,其聚类结果有一定的随机性,因此,取样点较多、且样点分布较均匀的聚类分析结果才有较高可信度。

DNA molecular markers produced by amplified fragment length polymorphism （AFLP） were used to detect genetic variation in 13 geographical populations of Chilo suppressalis （Walker） collected from 11 Chinese provinces. A total of 445 distinct alleles were amplified by three AFLP primer pairs from genomic DNA, of which 386 （86. 8% ） were found to be polymorphic. The coefficient of gene differentiation between populations was 0.74. Genetic identity between the 13 populations was greater than 0. 67. Cluster analysis showed that all the tested populations could be grouped into 4 clades. The northern Huai River plain clade was comprised of the GY, FN and FNing populations, the east-south region clade of the YX and MH populations, and the Jing-Xiang-Chuang plain clade of the JZ, SY and DY populations. This classification is credible in that the populations within each of the clades share similar climatic conditions and proximity. However, a single population with a relatively long genetic distance to all other populations probably belongs to a random clade. Investigations of genetic diversity between populations should use as many widely dispersed populations as possible.