Wang X R, Szmidt A E, Savolainen O
Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, 100093 Beijing, China.
Genetics. 2001 Sep;159(1):337-46. doi: 10.1093/genetics/159.1.337.
Pinus densata has been suggested to have originated from hybridization events involving P. tabulaeformis and P. yunnanensis. In this study, allozyme differentiation at 12 loci was studied in 14 populations of P. tabulaeformis, P. densata, and P. yunnanensis from China. The observed genetic composition of P. densata supported the hybrid hypothesis and showed varying degrees of contribution from P. yunnanensis and P. tabulaeformis among its populations. These data, together with previous chloroplast DNA results, indicated different evolutionary histories among P. densata populations. To examine the possibility of ongoing hybridization among the three species, we analyzed patterns of linkage disequilibria between allozyme loci in ovule, pollen, and zygote pools. None of these tests suggested that there is significant ongoing gene exchange, implying that populations of P. densata have a stabilized hybrid nature. The normal fertility and high fecundity of P. densata indicate that this hybrid is maintained through sexual reproduction. P. densata represents an example of diploid hybrid speciation in an extreme ecological habitat that is both spatially and ecologically separated from that of its parents.
高山松被认为起源于油松和云南松之间的杂交事件。在本研究中，我们对来自中国的14个油松、高山松和云南松种群的12个位点的等位酶分化进行了研究。观察到的高山松遗传组成支持杂交假说，并显示其种群中云南松和油松的贡献程度各不相同。这些数据与之前叶绿体DNA的结果一起，表明高山松种群之间存在不同的进化历史。为了检验这三个物种之间正在进行杂交的可能性，我们分析了胚珠、花粉和受精卵池中同工酶位点之间的连锁不平衡模式。这些测试均未表明存在显著的正在进行的基因交换，这意味着高山松种群具有稳定的杂交性质。高山松正常的育性和高繁殖力表明这种杂种是通过有性繁殖维持的。高山松代表了二倍体杂交物种形成的一个例子，它处于一个极端的生态栖息地，在空间和生态上都与其亲本物种相分离。
