RAPD标记研究马褂木地理种群的遗传分化

GENETIC DIFFERENTIATION OF GEOGRAPHIC POPULATIONS IN LIRIODENDRON CHINENSE USING RAPD MARKERS

利用RAPD标记对马褂木全分布区 15个种群的遗传多样性进行了分析。研究发现 ,马褂木具有丰富的遗传多样性 ,但东部种群因现有种群小 ,其遗传多样性明显地低于西部种群。种群遗传学研究揭示 ,由于小种群效应 ,以及缺乏有效的基因流和特有的致濒机制 ,马褂木种群间的遗传分化巨大 ,30 %以上的遗传变异存在于种群间。但在不同的地理区域 ,种群间的遗传分化程度不同。在西部分布区 ,地域上相距不远的种群其遗传距离较小 ,而在东部即使两个相邻的种群 ,其遗传距离也非常大。使用Nei’s遗传距离进行算术平均数的非加权成组配对法分析 (UPGMA) ,其聚类结果可以很好地将马褂木划分为西部和东部两个种源区 。

Genetic diversity of 15 populations from whole natural range of \%L.chinense\% was analyzed by using RAPD markers.It was found that \%L.chinense\% had a relatively high genetic diversity,but genetic diversity of the eastern populations was obviously less than that of the western because the eastern population had a small population size.Population genetics revealed that the small population effect,for lack of gene flow and special endangering mechanism resulted in a high genetic differentiation within populations which amounted to 34.34% of the genetic variation.Genetic differentiation among populations varied with geographic regions.Neighboring populations at eastern region showed large genetic differentiation,comparing with the western populations.The whole natural distribution range of \%L.chinense\% might be divided obviously into the western and the eastern provenance zone,the former could be further subdivided into Southwest and Center China subzone by cluster analysis(UPGMA) based on Nei's unbiased genetic distance.