利用RAPD标记分析卧龙自然保护区不同海拔沙棘种群的遗传变异

从1800m到3400m五个海拔连续取样,用RAPD分子标记研究了卧龙自然保护区中国沙棘种群的遗传结构和遗传变异.用11条寡核苷酸引物,扩增得到151个重复性好的位点,其中143个多态位点,多态率达94.7%.在5个沙棘种群中,总遗传多样性值(HT)为0.289,B种群内的遗传多样性值为0.315,这完全符合沙棘这种多年生、远交的木本植物高遗传变异的特性.5个种群内遗传多样性随海拔升高呈低—高—低变异趋势,在2200m海拔处的B种群遗传多样性达最大值0.315,3400m海拔处的E种群则表现最小,仅0.098.5个种群间的遗传分化值GST=0.406,也即是说有40.6%的遗传变异存在于种群间,59.4%存在种群内.1800m海拔处的A种群与其他种群的明显分离是造成种群间遗传分化大的原因.UPGMA聚类图和PCoA散点图分别进一步确证了5个种群间关系和所有个体间的关系.最后,经过Mantel检测,遗传距离与海拔表现了明显的相关性(r=0.646,P=0.011).

Genetic Variation of Hippophae rhamnoides Populations at Different Altitudes in the Wolong Nature Reserve Based on RAPDs

To estimate genetic variation and genetic structure of Hippophae rhamnoides ssp. sinensis at different altitudes, five natural populations in the Wolong Nature Reserve at altitudes ranging from 1 800 to 3 400 m above sea level (a.s.l.) were surveyed using random amplified polymorphic DNA markers (RAPDs). Based on 11 decamer primers, a total of 151 reproducible DNA loci were yielded, and 143 of them were polymorphic, accounting for 94.7%. Among the five populations investigated, the total gene diversity (HT) and gene diversity within population B equaled 0.289 and 0.315, respectively, which are modest for a subspecies of H. rhamnoides that is an outcrossed and long-lived woody plant. The amount of genetic variation among populations varied from 0.098 within population E (3 400 m a.s.l.) to 0.315 within population B (2 200 m a.s.l.). The coefficient of gene differentiation (GST) among populations equaled 0.406, and revealed that 40.6% of the genetic variance existed among populations and 59.4% within populations. The population A (1 800 m a.s.l.) differed greatly from the other four populations, which contributes to high genetic differentiation. A UPGMA cluster analysis and principal coordinate analyses based on Nei's genetic distances further corroborated the relationships among the five populations and all the sampling individuals, respectively. Mantel tests detected a significant correlation between genetic distances and altitudinal gradients (r=0.646, P=0.011).