種間雜交可以導(dǎo)致基因或基因組在種間滲透以及分類上的混亂,。張亞平院士,，云南大學(xué)于黎研究員和博士生劉江通過分析124個(gè)中國兔鼠物種個(gè)體的線粒體基因和核基因序列,，第一次發(fā)現(xiàn)在6個(gè)中國兔屬物種間存在著通過種間雜交而導(dǎo)致的基因滲透,。令人驚奇的是,，東北兔的線粒體完全被來自雪兔和華南兔的線粒體所替代,。此外,，核基因分析發(fā)現(xiàn)在中國兔屬物種間存在高比例的雜合子，在多個(gè)物種間有共享單倍型,，提示中國兔屬物種間的核基因的滲透是一個(gè)正在發(fā)生的過程,。因此，推測由頻繁的雜交事件所導(dǎo)致的形態(tài)上的過渡類型以及非典型的線粒體基因組世系的存在可能是導(dǎo)致中國兔屬物種分類混亂的真正原因,。
該研究結(jié)果近期發(fā)表在BMC Evolutionary Biology刊物上,。(生物谷 Bioon.com)
doi:BMC Evolutionary Biology 2011, 11:223
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PMID:
Reticulate evolution: frequent introgressive hybridization among Chinese hares (genus Lepus) revealed by analyses of multiple mitochondrial and nuclear DNA loci
Jiang LiuLi YuMichael ArnoldChun-Hua WuShi-Fang WuXin LuYa-Ping Zhang
Interspecific hybridization may lead to the introgression of genes and genomes across species barriers and contribute to a reticulate evolutionary pattern and thus taxonomic uncertainties. Since several previous studies have demonstrated that introgressive hybridization has occurred among some species within Lepus, therefore it is possible that introgressive hybridization events also occur among Chinese Lepus species and contribute to the current taxonomic confusion. Results: Data from four mtDNA genes, from 116 individuals, and one nuclear gene, from 119 individuals, provides the first evidence of frequent introgression events via historical and recent interspecific hybridizations among six Chinese Lepus species. Remarkably, the mtDNA of L. mandshuricus was completely replaced by mtDNA from L. timidus and L. sinensis. Analysis of the nuclear DNA sequence revealed a high proportion of heterozygous genotypes containing alleles from two divergent clades and that several haplotypes were shared among species, suggesting repeated and recent introgression. Furthermore, results from the present analyses suggest that Chinese hares belong to eight species. Conclusion: This study provides a framework for understanding the patterns of speciation and the taxonomy of this clade. The existence of morphological intermediates and atypical mitochondrial gene genealogies resulting from frequent hybridization events likely contribute to the current taxonomic confusion of Chinese hares. The present study also demonstrated that nuclear gene sequence could offer a powerful complementary data set with mtDNA in tracing a complete evolutionary history of recently diverged species.
