State Key Laboratory of Grassland Agro-Ecosystems and College of Ecology, Lanzhou University, Lanzhou, 730000, China.
Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China.
New Phytol. 2022 Apr;234(2):392-404. doi: 10.1111/nph.17956. Epub 2022 Jan 30.
The Qinghai-Tibet Plateau (QTP) sensu lato (sl), comprising the platform, the Himalaya and the Hengduan Mountains, is characterized by a large number of endemic plant species. This evolutionary cradle may have arisen from explosive species diversification because of geographic isolation. However, gene flow has been widely detected during the speciation processes of all groups examined, suggesting that natural selection may have also played an important role during species divergence in this region. In addition, natural hybrids have been recovered in almost all species-rich genera. This suggests that numerous species in this region are still 'on the speciation pathway to complete reproductive isolation (RI)'. Such hybrids could directly develop into new species through hybrid polyploidization and homoploid hybrid speciation (HHS). HHS may take place more easily than previously thought through alternate inheritance of alleles of parents at multiple RI loci. Therefore, isolation, selection and hybridization could together have promoted species diversification of numerous plant genera on the QTP sl. We emphasize the need for identification and functional analysis of alleles of major genes for speciation, and especially encourage investigations of parallel adaptive divergence causing RI across different lineages within similar but specific habitats in this region.
青藏高原（QTP）广义概念（sl）包括高原、喜马拉雅山和横断山脉，其特点是拥有大量的特有植物物种。这个进化的摇篮可能是由于地理隔离导致的物种爆炸性多样化而产生的。然而，在所有被研究的群体的物种形成过程中，基因流已经被广泛检测到，这表明自然选择在该地区的物种分化过程中也可能发挥了重要作用。此外，几乎在所有物种丰富的属中都发现了天然杂种。这表明该地区的许多物种仍然处于“通过完全生殖隔离（RI）完成的物种形成途径上”。这些杂种可以通过杂种多倍体化和同倍体杂种形成（HHS）直接发育成新的物种。通过在多个 RI 位点上交替遗传亲本的等位基因，HHS 可能比以前认为的更容易发生。因此，隔离、选择和杂交可能共同促进了青藏高原 sl 上众多植物属的物种多样化。我们强调需要识别和功能分析用于物种形成的主要基因的等位基因，特别是鼓励在该地区类似但特定的生境中，对不同谱系之间导致 RI 的平行适应性分歧进行调查。
