【摘要】 由于不同种群遗传多样性的不均匀分布以及资金和人力资源等的限制 ,加上经济发展常与生物多样性保护存在矛盾 ,对于珍稀濒危物种等需要确定优先保护的种群。确定优先保护种群有 3种途径 :一是以种群遗传变异为依据 ,这一方法常用于指导种质资源收集 ;二是遗传差异为依据 ,如进化显著单元 ;三是以综合考虑种群内遗传变异和遗传差异的遗传贡献率为依据。前两种方法各自考虑了一个方面 ,存在一定缺陷 ,第 3种方法弥补了这种不足 ,但是目前缺少计算遗传贡献率的模型。采用等位基因丰富度参数 ,从种群内遗传变异、种群间遗传变异以及物种水平遗传变异之间的关系出发 ,提出了将种群间遗传变异分配到各种群的模型 ,以及计算各种群遗传贡献的方法。利用获得的 6个银杏种群 cp DNA PCR- RFL P单倍型数据对模型进行了说明 ,并根据计算结果得出金佛山、妥乐种群位于需要优先保护前列的初步结果更多还原

【Abstract】 Due to the uneven distribution of genetic variation and therefore differences in the significance of populations, limits of fund and human resources, and the contradiction usually occurred between conservation and economic development, we had to decide what and where to conserve the threatened species, though all populations should be conserved effectively. Genetic diversity-based methods in germplasm collections and genetic distinctiveness-based methods in identifying evolutionarily significant units （ESUs） can also be used in determining populations for priority conservation. However, each of them considers one aspect of contribution of a population to genetic variation at species level. Genetic variation includes two parts: variation within populations and among populations. Although lots of methods have been proposed to estimate these two parts, no method was available to determine the contribution of a specific population to the variation among populations, and further genetic contribution to the genetic variation at species level. We expanded the relationship between species richness at local and regional levels, β=γ/-1, suggested by Whittaker, to the relationship between allele richness at population and species levels,R_T=R_S+R_D, where R_T, R_S and R_D are allele richness at species and population levels and distinctiveness among populations, respectively. We constructed models to estimate the relative contribution of allele richness and distinctiveness of a specific population to the species level, C_RS（k）=(R_S（k）-_S)/R_T, C_RD（k）=(R_D（k）-_D)/R_T, respectively. Models to evaluate the genetic contributions of populations (C_RT（k）=(R_T（k）-_T)/R_T) were also proposed. At last, we evaluated the genetic contributions of six G. biloba populations based on cpDNA haplotypes. Genetic contributions of Jinfoshan and Tuole populations were 34.52% and 8.34%, respectively, and should be conserved with the highest priority.更多还原