Artyukova E V, Kozyrenko M M, Kholina A B, Zhuravlev Y N
Institute of Biology and Soil Science, Far East Branch of Russian Academy of Sciences, Vladivostok, Russia.
Genetica. 2011 Feb;139(2):221-32. doi: 10.1007/s10709-010-9539-8. Epub 2010 Dec 16.
Oxytropis chankaensis Jurtz. (Fabaceae) is an endangered perennial tetraploid species endemic to the Khanka Lake coast. In Russia, O. chankaensis is distributed across a very restricted zone along the western shore of this lake. To characterise all known populations of this species, we assessed the genetic diversity of four noncoding regions of chloroplast DNA (cpDNA). Variable sites detected within the trnL-trnF, the petG-trnP, and the trnS-trnG regions allowed the identification of seven haplotypes. On the other hand, no variation was found in the trnH-psbA region. O. chankaensis exhibited an overall low level of nucleotide diversity (π = 0.00052) but a marked haplotype diversity (h = 0.718). A combination of three or four haplotypes was found in each population, and most of the cpDNA variation (above 90%) was distributed within populations. The level of genetic structure that we detected in O. chankaensis using maternal plastid DNA markers was much lower (G (ST) = 0.037) than the average that is estimated for angiosperms. We found no evidence for isolation by distance or for phylogeographic structuring in O. chankaensis. Our data suggest that autopolyploidy has arisen more than once in the evolutionary history of this species. Repetitive expansion and contraction during past and ongoing demographic events both seem to be involved in shaping the current genetic structure of O. chankaensis. This study provides valuable information for developing the most appropriate strategy for conserving this endemic species with a narrow habitat range.
长白棘豆（豆科）是一种濒危的多年生四倍体物种，为兴凯湖沿岸特有。在俄罗斯，长白棘豆分布于该湖西岸一个非常有限的区域。为了描述该物种所有已知种群的特征，我们评估了叶绿体DNA（cpDNA）四个非编码区的遗传多样性。在trnL-trnF、petG-trnP和trnS-trnG区域检测到的可变位点可鉴定出7种单倍型。另一方面，trnH-psbA区域未发现变异。长白棘豆的核苷酸多样性总体水平较低（π = 0.00052），但单倍型多样性显著（h = 0.718）。每个种群中发现了三种或四种单倍型的组合，并且大多数cpDNA变异（超过90%）分布在种群内部。我们使用母系质体DNA标记在长白棘豆中检测到的遗传结构水平（G(ST) = 0.037）远低于被子植物的平均估计值。我们没有发现长白棘豆存在距离隔离或系统发育地理结构的证据。我们的数据表明，在该物种的进化历史中，同源多倍体不止一次出现。过去和当前人口事件中的反复扩张和收缩似乎都参与了塑造长白棘豆当前的遗传结构。本研究为制定保护这种栖息地范围狭窄的特有物种的最合适策略提供了有价值的信息。
