Mateu-Andrés Isabel
Instituto Cavanilles de Biodiversidad y Biología Evolutiva, C/Dr. Moliner 50, E-46100 Burjassot, Valencia, Spain.
Ann Bot. 2004 Dec;94(6):797-804. doi: 10.1093/aob/mch204. Epub 2004 Oct 11.
This study was designed to compare levels of genetic variation and its partitioning in three related species of Antirrhinum, A. subbaeticum, A. pertegasii and A. pulverulentum, and to check the hypothesis that species with small total population size have lower levels of genetic variability than those with bigger ones. This information should contribute to the development of conservation strategies of rare endemic species of Antirrhinum.
One hundred and seventy-seven plants were screened for variability at 14 allozyme loci by means of horizontal starch gel. Parameters of genetic diversity, and its partitioning, were calculated. An indirect estimate of gene flow was based on the equation: Nm = (1 - GST)/4GST.
Genetic variabilities in A. subbaeticum and A. pertegasii were found to be the lowest known for the genus, the within-population genetic diversity being correlated with population size in both species. The distribution of genetic diversity is strikingly different among species, with 85 % of the total variation distributed among populations in A. subbaeticum, 6 % in A. pertegasii and 23 % in A. pulverulentum. Estimated levels of gene flow were negligible for A. subbaeticum (0.04), high for A. pertegasii (3.92), and substantial for A. pulverulentum (0.83). Genetic and geographic distances were negatively correlated in A. pertegasii, whereas no significant correlation was found in the other two species.
Levels of total genetic diversity agree with the hypothesis that species with small total population size have lower levels of genetic variability than those with bigger ones. Strategies for the conservation of the species are recommended, such as preservation of natural populations and avoidance of possible causes of threat, as well as ex situ preservation of seeds, reinforcement of small populations of A. subbaeticum with plants or seeds from the same population, and avoidance of translocations among populations.
本研究旨在比较三种相关的金鱼草属植物，即苏贝蒂金鱼草（Antirrhinum subbaeticum）、佩尔泰加斯金鱼草（A. pertegasii）和粉状金鱼草（A. pulverulentum）的遗传变异水平及其分配情况，并检验以下假设：总种群规模较小的物种比总种群规模较大的物种具有更低的遗传变异性。这些信息应有助于制定金鱼草属稀有特有物种的保护策略。
通过水平淀粉凝胶对177株植物的14个等位酶位点的变异性进行筛选。计算遗传多样性参数及其分配情况。基于公式Nm = (1 - GST)/4GST对基因流进行间接估计。
发现苏贝蒂金鱼草和佩尔泰加斯金鱼草的遗传变异性是该属已知的最低水平，两个物种的种群内遗传多样性均与种群规模相关。遗传多样性在物种间的分布差异显著，苏贝蒂金鱼草中85%的总变异分布在种群间，佩尔泰加斯金鱼草中为6%，粉状金鱼草中为23%。苏贝蒂金鱼草的估计基因流水平可忽略不计（0.04），佩尔泰加斯金鱼草的基因流水平较高（3.92），粉状金鱼草的基因流水平可观（0.83）。在佩尔泰加斯金鱼草中，遗传距离与地理距离呈负相关，而在其他两个物种中未发现显著相关性。
总遗传多样性水平与以下假设一致，即总种群规模较小的物种比总种群规模较大的物种具有更低的遗传变异性。建议采取物种保护策略，如保护自然种群、避免可能的威胁因素，以及进行种子的迁地保存、用同一种群的植物或种子增强苏贝蒂金鱼草的小种群数量，避免种群间的迁移。
