Genetic Variability in Natural Populations of Cassia grandis L. F.

ABSTRACT The design of strategies for genetic conservation requires knowledge of the ecologic and genetics aspects of the target species populations. This work aimed to characterize genetically natural populations of Cassia grandis L. F. using isozymes. Genetic diversity was analyzed by allele frequencies ( P ^ i j ) and the following diversity indexes: observed ( H ^ e ) and expected ( H ^ e )average heterozygosity, average number of alleles per locus ( A ^ ) and percentage of polymorphic loci ( P ^); and the genetic structure of populations by Wright's statistics. We estimated gene flow, population effective size and the minimum viable population in the short and long time. The observed results conclude that the studied populations of C. grandis are structured, which can be demonstrated by observation of rare and exclusive alleles, and high genetic diversity among them.

摘要：遗传保护策略的制定，需充分掌握目标物种种群的生态学与遗传学特征。本研究采用同工酶（isozymes）技术，对美丽决明（Cassia grandis L. F.）的自然种群开展遗传学特征解析。研究通过等位基因频率（$P^i_j$）、观测杂合度（$H^e$）与期望杂合度（$H^e$）、每位点平均等位基因数（$A^$）以及多态位点百分率（$P^$）等多样性指数分析遗传多样性，并借助赖特统计量（Wright's statistics）解析种群遗传结构；同时估算了种群的基因流、有效种群大小以及短、长期最小存活种群（minimum viable population）。研究结果显示，本次研究的美丽决明（C. grandis）种群具有遗传结构，该结论可通过稀有等位基因与特有等位基因的检出，以及种群间较高的遗传多样性得到佐证。