Demographic history and interspecific hybridization of four Shorea species (Dipterocarpaceae) from Peninsular Malaysia inferred from nucleotide polymorphism in nuclear gene regions
Demographic history and interspecific hybridization of four Shorea species (Dipterocarpaceae) from Peninsular Malaysia inferred from nucleotide polymorphism in nuclear gene regions
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DOI：
10.1139/x07-218
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发表时间：
2008-05-01
影响因子：
2.2
通讯作者：
Szmidt, Alfred E.
中科院分区：
文献类型：
--
作者：
Ishiyama, Hiroko;Inomata, Nobuyuki;Szmidt, Alfred E.
Shorea acuminata Dyer、Shorea curtisii Dyer ex King、Shorea leprosula Miq. 和 Shorea parvifolia Dyer 是马来西亚半岛热带雨林的优势树种，在更新世期间经历了几次气候变化。为了调查这些物种当前的种群结构和人口统计历史，我们分析了核基因区域 PgiC 的核苷酸多态性水平和模式。我们还使用了之前研究中获得的 GapC 基因区域的序列数据。在 S. curtisii、S. leprosula 和 S. parvifolia 的两个研究基因区域中观察到的负 Tajima D 值意味着所有三个物种都经历了种群扩张事件。 S. acuminata 和 S. curtisii 的种群分化程度较低至中等程度表明，在马来西亚半岛的冰期后殖民化之后，最近调查的种群出现了分歧。此外，一些单倍型与其他物种的单倍型相似或相同。这种单倍型的存在可以部分地通过种间杂交来解释。事实上，我们发现了一些假定的混血个体。密切相关物种之间的种间杂交可能有助于所研究物种的多态性。
Shorea acuminata Dyer, Shorea curtisii Dyer ex King, Shorea leprosula Miq., and Shorea parvifolia Dyer are dominant tree species in the tropical rainforest of Peninsular Malaysia, which experienced several climatic changes during Pleistocene. To investigate the current population structure and demographic history of these species, we analyzed levels and patterns of nucleotide polymorphism of the nuclear gene region PgiC. We also used sequence data of the GapC gene region obtained in our previous study. Negative Tajima's D values observed in both investigated gene regions for S. curtisii, S. leprosula, and S. parvifolia implied that all three species have experienced population expansion events. Little to moderate levels of population differentiation in S. acuminata and S. curtisii suggested recent divergence of the investigated populations after postglacial colonization of the Peninsular Malaysia. In addition, some haplotypes were similar or identical to haplotypes of the other species. The existence of such haplotypes could be partially explained by interspecific hybridization. Indeed, we found some putative hybrid individuals. Interspecific hybridization among closely related species might have contributed to the polymorphism of the investigated species.