Knowledge Management System of Northwest Institute of Plateau Biology, CAS
Origin of the Qinghai-Tibetan Plateau endemic Milula (Liliaceae): further insights from karyological comparisons with Allium | |
Tang, HG ; Meng, LH ; Ao, SQ ; Liu, JQ | |
2005-10-01 | |
发表期刊 | CARYOLOGIA
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摘要 | Milula, a monotypic genus endemic to the Qinghai-Tibetan Plateau, was found to be nested deeply within Allium by the molecular phylogeny despite the aberrant morphology. It remains unknown what had contributed to the rapid evolution of morphology and origin of this exceptional species. In contrast to a previous report of its karyotypes with 2n = 16 = 8M+8SM (2SAT), similar to most species of Allium, a rather different karyotype, 2n = 20 = 4M +10SM+6T (2SAT), was found in examined 31 individuals from 6 populations of M. spicata distributed in the central Tibet. Karyotypes of 7 Allium species occurring in the Qinghai-Tibetan Plateau were further reported. The basic number x = 8 was confirmed for all of them and their karyotypes consist mainly of metacentric and submetacentric chromosomes with rare subterminal and terminal chromosomes. The karyotype of M. spicata is distinctly different from that of most Allium species occurring in the plateau through a complete comparison of all available species in this region and adjacent areas. However, the same chromosome number and similar karyotypic structure were found in A. fasciculatum of Sect. Bromatorrhiza, indicating a possible close relationship between them. But this similarity is contradictory to the preliminary molecular phylogenetic analysis that Milula was closely related to A. cyathophorum of Sect. Bromatorrhiza with x=8, but the other species with x=10 and 11 in this section were clearly placed in the other clade. We therefore suggested that the paralleling evolution from x=8 to x=9, 10 and 11 with increasing asymmetry of karyotype possibly due to the chromosomal Robertsonian translocation might occur separately in the two recognized phylogenetic lineages of Allium. In addition to aneuploidy and following change of the chromosomal structures, the habitat isolation due to the recent uplift of the Qinghai-Tibetan Plateau and the Quaternary climatic oscillation, plays a greater role in origin of Milula and other endemic species (genera) with aberrant morphology from their progenitors.; Milula, a monotypic genus endemic to the Qinghai-Tibetan Plateau, was found to be nested deeply within Allium by the molecular phylogeny despite the aberrant morphology. It remains unknown what had contributed to the rapid evolution of morphology and origin of this exceptional species. In contrast to a previous report of its karyotypes with 2n = 16 = 8M+8SM (2SAT), similar to most species of Allium, a rather different karyotype, 2n = 20 = 4M +10SM+6T (2SAT), was found in examined 31 individuals from 6 populations of M. spicata distributed in the central Tibet. Karyotypes of 7 Allium species occurring in the Qinghai-Tibetan Plateau were further reported. The basic number x = 8 was confirmed for all of them and their karyotypes consist mainly of metacentric and submetacentric chromosomes with rare subterminal and terminal chromosomes. The karyotype of M. spicata is distinctly different from that of most Allium species occurring in the plateau through a complete comparison of all available species in this region and adjacent areas. However, the same chromosome number and similar karyotypic structure were found in A. fasciculatum of Sect. Bromatorrhiza, indicating a possible close relationship between them. But this similarity is contradictory to the preliminary molecular phylogenetic analysis that Milula was closely related to A. cyathophorum of Sect. Bromatorrhiza with x=8, but the other species with x=10 and 11 in this section were clearly placed in the other clade. We therefore suggested that the paralleling evolution from x=8 to x=9, 10 and 11 with increasing asymmetry of karyotype possibly due to the chromosomal Robertsonian translocation might occur separately in the two recognized phylogenetic lineages of Allium. In addition to aneuploidy and following change of the chromosomal structures, the habitat isolation due to the recent uplift of the Qinghai-Tibetan Plateau and the Quaternary climatic oscillation, plays a greater role in origin of Milula and other endemic species (genera) with aberrant morphology from their progenitors. |
文献类型 | 期刊论文 |
条目标识符 | http://210.75.249.4/handle/363003/20276 |
专题 | 中国科学院西北高原生物研究所 |
推荐引用方式 GB/T 7714 | Tang, HG,Meng, LH,Ao, SQ,et al. Origin of the Qinghai-Tibetan Plateau endemic Milula (Liliaceae): further insights from karyological comparisons with Allium[J]. CARYOLOGIA, Tang HG, Meng LH, Ao SQ, Liu JQ.Origin of the Qinghai-Tibetan Plateau endemic Milula (Liliaceae): further insights from karyological comparisons with Allium.CARYOLOGIA,2005,58(4):320-331,2005. |
APA | Tang, HG,Meng, LH,Ao, SQ,&Liu, JQ.(2005).Origin of the Qinghai-Tibetan Plateau endemic Milula (Liliaceae): further insights from karyological comparisons with Allium.CARYOLOGIA. |
MLA | Tang, HG,et al."Origin of the Qinghai-Tibetan Plateau endemic Milula (Liliaceae): further insights from karyological comparisons with Allium".CARYOLOGIA (2005). |
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