Evolutionary trends of the mitochondrial lineage differentiation in species of genera Martes and Mustela

We compared partial sequences (402 bp) of the mitochondrial cytochrome b gene in 68 individuals of martens (Martes), weasels (Mustela) and their relatives from the Northern Hemisphere to identify the modes of geographic differentiation in each species. We then compared complete sequences (1140 bp) of the gene in 17 species of the family Mustelidae to know the spatial and temporal modes of speciation, constructing linearized trees with transversional substitutions for deeper lineage divergences and with transversions and transitions for younger lineages. Our data suggested that these lineages of Martes and Mustela differentiated in a stepwise fashion with five radiation stages from the generic divergences (stage I) to the intraspecific divergences (stage V), during the last 10 or 20 million years as the fossil evidence suggests. In the lineage of Martes, the first offshoots are of Martes flavigula, M. pennanti, and Gulo gulo (stage II), the second is M. foina (stage III), and the third are M. americana, M. martes, M. melampus, and M. zibellina (stage IV). The divergence of the lineages of Mustela is likely to have taken place concurrently with the radiations of the Martes. These divergence processes are attributable in part to the geographic allocation along the two continents, North America and Eurasia, as well as among peripheral insular domains, such as Taiwan and the Japanese Islands. In addition, the Eurasian continent itself was shown to have been involved in the species diversification in the martens and weasels.

Mitochondrial cytochrome b gene sequence diversity in the Korean hare, Lepus coreanus Thomas (Mammalia, Lagomorpha)

Partial sequences of the mitochondrial cytochrome b gene of the Korean hare (Lepus coreanus) were analyzed to determine the degree of genetic diversity. Nine haPlotyes were observed, and the maximum Tamura-Nei nucleotide distance among them was 2.8%, indicating that genetic diversity of L. coreanus is moderate. In order to clarify the Korean hare's taxonomic status and relationship with the Manchurian hare (L. mandshuricus) and the Chinese hare (L. sinensis), these nine haplotypes of the Korean hare were compared with 13 haplotypes from five other species of eastern Asian Lepus including L. mandshwicus and L. sinensis. The Korean hare was distinct in its cytochrome b gene, and it is confirmed that L. coreanus is a valid species, as noted by Jones and Johnson (1965, Univ. Kansas Publ. (Mus. Nat. Hist.) 16:357). Further analyses of mtDNA cytochrome b gene with additional specimens of L. coreanus from North Korea and other species of Lepus from eastern Asia are needed to clarify the taxonomic status of the divergent mtDNA clades of L. mandshuricus and L. sinensis.

Mitochondrial DNA control region and cytochrome b sequence variation in the genus Mystacoleucus Gunther (Pisces : Cyprinidae : Barbinae) from China

Mitochondrial DNA (mtDNA) hypervariable segment I sequences (HVSI, 471 bp) of the control region and partial cytochrome b sequences (Cytb, 403 bp) were analyzed in three tentative species of the genus Mystacoleucus in China (M. chilopterus, M. marginatus, and M. lepturus). Not more than two mutations were found in both the HVSI and Cytb fragments among the samples from M. chilopterus and M. marginatus. However, M. lepturus differed from each of them by at least 25 mutations in Cytb and 51 mutations in HVSI. Moreover, the HVSI sequence variation within M. lepturus was larger than that between M. chilopterus and M. marginatus. Given that M. chilopterus and M. marginatus are very similar in morphology, it is reasonable to consider M. chilopterus and M. marginatus as conspecific. Our results also suggest a recent radiation of M. marginatus from downstream to upstream of the Lancangjiang (Mekong) River.

Molecular phylogeny of wood mice (Apodemus, Muridae) in East Asia

Sequences of the mitochondrial cytochrome b (1140 bp) and nuclear IRBP (1152 bp) genes were used to assess the evolutionary history of Apodemus, using the complete set of Asian species. Our results indicate that speciation in Asia involved three radiations, which supports an earlier study. The initial radiation yielded A. argenteus (Japanese endemic), A. gurkha (Nepalese endemic), and the ancestral lineage of the remaining Asian species. This lineage subsequently diverged into four groups: agrarius-chevrieri (agrarius group), draco-latronum-semotus (draco group), A. peninsulae, and A. speciosus (Japanese endemic). The final step consisted of divergence within two species groups as a consequence of the geography of the Yunnan-Guizhou plateau and Taiwan. The ecological ability of two Apodemus-species to inhabit one locality via niche partitioning likely drove the second radiation and shaped the basic geographical pattern seen today: A. argenteus and A. speciosus in Japan, A. agrarius and A. peninsulae in northern China, and the A. agrarius and A. draco groups in southern China. The three radiations are estimated to have occurred 7.5, 6.6, and 1.8-0.8 Mya respectively, using the IRBP clock, based on rat-mouse divergence 12 Mya. (C) 2003 The Linnean Society of London.

Late Pleistocene divergence and subsequent population expansion of two closely related fish species, Japanese anchovy (Engraulis japonicus) and Australian anchovy (Engraulis australis)

Climatic oscillations during the Pleistocene ice ages produced great changes in species' geographical distribution and abundance, which could be expected to have genetic consequences. Living in the temperate upwelling zones of the northwestern Pacific, Ja

Differential population structuring and demographic history of two closely related fish species, Japanese sea bass (Lateolabrax japonicus) and spotted sea bass (Lateolabrax maculatus) in Northwestern Pacific

The Quaternary cold periods in the Northwestern Pacific are thought to have heavily influenced the amount and distribution of intraspecific genetic variation in marine fishes. To estimate the demographic history and genetic structure of Lateolabrax macula

Mitochondrial Cytochrome b Sequence Variations and Population Structure of Siberian Chipmunk (Tamias sibiricus) in Northeastern Asia and Population Substructure in South Korea

Twenty-five chipmunk species occur in the world, of which only the Siberian chipmunk, Tamias sibiricus, inhabits Asia. To investigate mitochondrial cytochrome b sequence variations and population structure of the Siberian chipmunk in northeastern Asia, we

Analysis of mitochondrial DNA variants in Japanese patients with schizophrenia

To test the hypothesis that mitochondrial DNA (mtDNA) variants contribute to the susceptibility to schizophrenia, we sequenced the entire mtDNAs from 93 Japanese schizophrenic patients. Three non-synonymous homoplasmic variants in subunit six of the ATP s

Anti-HIV-1 Activities of Hemslecins A and B

目的:研究从药用植物金佛山雪胆分离的雪胆素A和雪胆素B两个三萜类化合物的体外抗HIV活性.方法:应用合胞体抑制实验、p24抗原产生的抑制实验、慢性感染细胞和正常细胞间的细胞融合抑制实验等技术检测化合物的体外抗HIV-l活性;利用HIV-l逆转录酶、蛋白酶抑制实验,NCp7锌离子逐出实验探讨化合物的作用机制.结果:雪胆素A和雪胆素B在体外有较好的抑制HIV-l活性,其活性主要表现为:(1)抑制HIV-l诱导合胞体形成,EC50值分别为3.09 μg·mL-1和2.53μg·mL-1;(2)抑制HIV- 急性感染的C8106细胞p24抗原产生,EC50值分别为3.97μg·mL-1和18.90μg·mL-1;(3)抑制HIV-1 慢性感染H9与正常C8166细胞间融合,EC50分别为1.76μg·mL-1和11.95μg·mL-1.雪胆素A和雪胆素B对HIV-l逆转录酶、蛋白酶、NCp7锌离子逐出均没有抑制作用.雪胆素A对HIV-1整合酶有微弱的结合活性,而雪胆素B对HIV-1整合酶没有结合活性.在共培养实验中,雪胆素A和雪胆素B预处理C8166细胞组比未经预处理细胞组能够更有效的抑制HIV-l活性.结论:化合物雪胆素A和雪胆素B体外有较好的抗HIV-1活性,可能主要作用于HIV-1病毒进入细胞阶段.

槐花提取化合物K3体外抗HIV-1活性的研究

目的:研究槐花提取化合物K3的体外抗HIV-1活性,并对其抗HIV-1机制进行初步探讨.方法:采用MTT比色法检测化合物对各种细胞的毒性.用合胞体形成计数法,p24抗原捕获ELISA法及RT-PCR等多种方法研究化合物体外抗HIV-1活性.结论:槐花提取化合物K3体外有较好的抗HIV-1活性,能够抑制病毒实验株(HIV-1ⅢB,耐药株(HIV-1 74v)和临床分离株(HIV-1KM018)等多种病毒株的复制,且其作用机制是多靶点的,不仅可以抑制病毒的进入,还可以抑制HIV-1逆转录酶活性.

银额果蝇B染色体特异性基因的初步研究

采用代表性差异分析法(RDA)研究了银额果蝇两个单雌系AKM46(含B染色体)和AGZ2(不含B染色体)两基因组间的差异。用AKM46作检测(tester)扩增子,AGZ2作驱赶(driver)扩增子,通过三轮消减杂交后,获得了6个差异片段(100bp-300bp)。实验证实了其中两个片段来自含有B染色体的单雌系AKM46,而且可能是B染色体上的特异基因片段。

中国银额果蝇自然群体B染色体的分布

中国(台湾省外)银额果蝇自然群体中普遍存在Bs。结合前人报道提出,Bs频率的地理分布出现了由东向西和由南向北的规律性的依次升高趋势。这种跨越不同地理环境的区域性梯度变异与其宿主向大陆内地扩散的推论相符。Bs频率最高(87.7%)的是海南岛的孤立隔离群体。大部分群体含Bs的数目多,最多达14条,为标准染色体数目(2n=6)的2.3倍。同时依据该果蝇Bs频率的地理分布特点,将我国现生的银额果蝇划归为5个生态型群体,即沿海丘陵群体、高原型群体、岛屿型群体、山地型群体和峡谷群体等。