State Key Laboratory of Earth Surface Processes and Resource Ecology & College of Life Sciences, Beijing Normal University Beijing, 100875, China.
Ecol Evol. 2014 Nov;4(22):4370-9. doi: 10.1002/ece3.1295. Epub 2014 Oct 28.
Historical climate change can shape the genetic pattern of a species. Studies on this phenomenon provide great advantage in predicting the response of species to current and future global climate change. Chinese seabuckthorn (Hippophae rhamnoides subsp. sinensis) is one of the most important cultivated plants in Northwest China. However, the subspecies history and the potential genetic resources within the subspecies range remain unclear. In this study, we utilized two intergenic chloroplast regions to characterize the spatial genetic distribution of the species. We found 19 haplotypes in total, 12 of which were unique to the Chinese seabuckthorn. The populations observed on the Qinghai-Tibet Plateau (QTP) consisted of most of the haplotypes, while in the northeast of the range of the subspecies, an area not on the QTP, only four haplotypes were detected. Our study also revealed two distinct haplotype groups of the subspecies with a sharp transition region located in the south of the Zoige Basin. 89.96% of the genetic variation located between the regions. Mismatch analysis indicated old expansions of these two haplotype groups, approximately around the early stage of Pleistocene. Additional morphological proofs from existing studies and habitat differentiation supported a long independent colonization history among the two regions. Potential adaptation probably occurred but needs more genome and morphology data in future. Chinese seabuckthorn have an older population expansion compared with subspecies in Europe. The lack of large land ice sheets and the heterogeneous landscape of the QTP could have provided extensive microrefugia for Chinese seabuckthorn during the glaciation period. Multiple localities sustaining high-frequency private haplotypes support this hypothesis. Our study gives clear insight into the distribution of genetic resources and the evolutionary history of Chinese seabuckthorn.
历史气候变化可以塑造物种的遗传模式。对这一现象的研究在预测物种对当前和未来全球气候变化的反应方面具有很大的优势。中国沙棘（Hippophae rhamnoides subsp. sinensis）是中国西北地区最重要的栽培植物之一。然而，亚种的历史和亚种范围内的潜在遗传资源仍不清楚。在本研究中，我们利用两个基因间叶绿体区域来描述物种的空间遗传分布。我们总共发现了 19 种单倍型，其中 12 种是中国沙棘特有的。在青藏高原（QTP）上观察到的种群包含了大多数的单倍型，而在亚种范围的东北部，一个不在 QTP 上的地区，只检测到了 4 种单倍型。我们的研究还揭示了亚种的两个不同的单倍型组，一个明显的过渡区域位于卓格盆地的南部。89.96%的遗传变异位于这两个区域之间。不匹配分析表明，这两个单倍型组大约在更新世早期发生了古老的扩张。来自现有研究的额外形态学证据和栖息地分化支持了这两个地区之间长期独立的殖民历史。可能发生了潜在的适应，但在未来需要更多的基因组和形态学数据。与欧洲的亚种相比，中国沙棘的种群扩张历史更为悠久。青藏高原上缺乏大型陆地冰盖和异质的景观，可能为沙棘在冰期提供了广泛的微生境。多个维持高频特有单倍型的地点支持了这一假说。本研究清晰地揭示了中国沙棘遗传资源的分布和进化历史。
