Maharramova Elmira H, Safarov Hajiaga M, Kozlowski Gregor, Borsch Thomas, Muller Ludo A
Botanischer Garten und Botanisches Museum Berlin-Dahlem, Freie Universität Berlin, 14195 Berlin, Germany Institute of Botany, Azerbaijan National Academy of Sciences, AZ1073 Baku, Azerbaijan.
Hirkan National Park, AZ4235 Lankaran, Azerbaijan.
Am J Bot. 2015 Jan;102(1):119-28. doi: 10.3732/ajb.1400370. Epub 2015 Jan 6.
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The Caucasus represents one of the world's biodiversity hotspots and includes the climatic refugia Hyrcan on the southern coast of the Caspian Sea and Colchis on the eastern coast of the Black Sea, where different species survived during the Quaternary climatic oscillations. We evaluated the genetic diversity of the relict tree Zelkova carpinifolia shared between the two refugia and distributed throughout the Caucasus and adjacent areas.•
Specimens were collected from 30 geographical sites in Azerbaijan, Georgia, Iran, and Turkey and screened for variability at eight nuclear microsatellite loci. The genetic diversity among and within populations was assessed using a set of statistical measures.•
We detected 379 different genotypes from a total of 495 individuals with varying degrees of clonal reproduction at the different sites. Low to intermediate levels of genetic diversity were observed at all sites, and strong differentiation between sampling sites was absent. In addition, we observed no clear genetic differentiation between the Colchis and Hyrcan. Bayesian clustering of the genotypes revealed three populations with high levels of admixture between the sampling sites.•
The lack of strong genetic structure of studied populations of Z. carpinifolia contrasts with a previous study based on chloroplast markers and suggests that long-distance pollen dispersal is an important factor of gene flow among populations of Z. carpinifolia. The present study does not reveal any particular site with particularly isolated genotypes that would deserve more attention for conservation purposes than others, although some sites should be considered for further investigation.
研究前提：高加索地区是世界生物多样性热点地区之一，包括里海南岸的希尔卡尼亚气候避难所和黑海东岸的科尔基斯气候避难所，在第四纪气候振荡期间，不同物种在这些地方得以幸存。我们评估了分布于高加索地区及相邻区域、在这两个避难所都存在的孑遗树种高加索 Zelkova carpinifolia 的遗传多样性。
方法：从阿塞拜疆、格鲁吉亚、伊朗和土耳其的30个地理位点采集样本，并对8个核微卫星位点的变异性进行筛选。使用一系列统计方法评估种群间和种群内的遗传多样性。
主要结果：在总共495个个体中检测到379种不同基因型，不同位点存在不同程度的克隆繁殖。所有位点均观察到低至中等水平的遗传多样性，采样位点之间没有明显分化。此外，我们未观察到科尔基斯和希尔卡尼亚之间存在明显的遗传分化。基因型的贝叶斯聚类分析显示有三个种群，采样位点之间存在高度混合。
结论：所研究的高加索 Zelkova carpinifolia 种群缺乏强烈的遗传结构，这与之前基于叶绿体标记的研究结果不同，表明长距离花粉传播是高加索 Zelkova carpinifolia 种群间基因流动的一个重要因素。本研究未发现任何具有特别孤立基因型的特定位点，这些位点比其他位点更值得在保护方面给予更多关注，不过有些位点应考虑进一步调查。
