High genetic differentiation among remnant populations of the endangered Caesalpinia echinata Lam. (Leguminosae-Caesalpinioideae)
High genetic differentiation among remnant populations of the endangered Caesalpinia echinata Lam. (Leguminosae-Caesalpinioideae)
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DOI：
10.1046/j.1365-294x.1998.00363.x
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发表时间：
1998-05-01
影响因子：
4.9
通讯作者：
De Oliveira, DE
中科院分区：
文献类型：
--
作者：
Cardoso, MA;Provan, J;De Oliveira, DE
在过去的400年里，巴西大西洋沿岸的森林碎片受到了广泛的人类活动的严重影响。刺苏木(Caesalpinia echinata，豆亚科Caesalpinioideae)在这一时期因其作为一种染料的经济价值而被过度开发。结果，该物种已经濒临灭绝，今天它的总种群数量受到了非常有限的限制。利用随机扩增多态性DNA(随机扩增多态性DNA)标记技术，对巴西木属5个自然居群的遗传变异分布进行了研究。在总的遗传变异中，28.5%归因于两个地理群体间的差异，29.6%归因于群体内的群体差异，42.0%归因于群体内的个体差异。观察到的高水平的种群分化与最初异交的多年生木本植物的预期相反，并表明可能存在一定程度的近亲繁殖。我们的结果与以前的研究一致，这些研究假设棘球绦虫总是以丛生形式出现，在一些地方很常见，但在两者之间很少见。从保护的角度来看，代表不同地区的不同种群应该受到保护，但不应在恢复过程中冒着遗传信息丢失和稀释的风险将不同来源的植物合成成种群。这项研究表明，在遗传距离和地理距离之间建立明确的相关性和识别最大多样性区域方面，随机扩增多态性DNA标记是有效的，可以作为评估该濒危物种遗传变异划分的初步方法。
Forest fragments along the Atlantic coastland of Brazil have been highly impacted by extensive human activities for the last 400 years. Caesalpinia echinata (Leguminosae-Caesalpinioideae), brazilwood, was overexploited during this period due to its economical importance as a dye. As a result, the species has become endangered and today its total population size is very restricted. We have assessed the distribution of genetic variation between five natural populations of brazilwood by means of RAPD (random amplified polymorphic DNA) markers. Of the total genetic variability, 28.5% was attributable to differences between two geographical groups, 29.6% to population differences within groups and 42.0% to individual differences within populations. The high level of population differentiation observed is in contrast to that expected for a primarily outcrossed woody perennial plant, and suggests that there may be a degree of inbreeding. Our results are in agreement with previous studies which postulated that C. echinata has always occurred in clumps, being common in some places but rare in between. From a conservation point of view, different populations representing different regions should be protected and, yet, plants with different origins should not be synthesized into populations in a recovery process at the risk of loss and dilution of genetic information. This study demonstrates that RAPD markers were effective in establishing a clear correlation between genetic and geographical distance and in identifying areas of maximum diversity, and may be used as an initial approach to assess the partitioning of genetic variation in this endangered species.