52 resultados para South East-Asia


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Partial (DNA) sequences were examined for one nuclear (28S rRNA gene) and one mitochondrial (16S rRNA) locus for nine species of pomatiopsid snail (Gastropoda: Rissooidea: Pomatiopsidae) from south-east Asia and south-west China. Fresh field samples were

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A total of 38 Amiota (s. str.) species (about 40% of the world total) are reported from southern China, with descriptions of 23 new species, i.e. sinuata species-group: aculeata Chen and Aotsuka, sp. nov., subsinuata Chen and Aotsuka, sp. nov., xishuangbanna Chen and Aotsuka, sp. nov.; basdeni species-group: brevipartita Chen and Gao, sp. nov., curvispina Chen and Gao, sp. nov., lipingae Chen and Gao, sp. nov., huae Chen and Gao, sp. nov., longispina Chen and Gao, sp. nov.; taurusata species-group: asymmetrica Chen and Takamori, sp. nov.; femorata Chen and Takamori, sp. nov., yixiangensis Chen and Takamori, sp. nov.; alboguttata species-group: ailaoshanensis Chen and Watabe, sp. nov., arcuata Chen and Watabe, sp. nov., dehiscentia Chen and Watabe, sp. nov., jizushanensis Chen and Watabe, sp. nov., latitabula Chen and Watabe, sp. nov., luguhuensis Chen and Watabe, sp. nov., nozawai Chen and Watabe, sp. nov., paraspinata Chen and Watabe, sp. nov., shangrila Chen and Watabe, sp. nov.; and ungrouped: fuscicata Chen and Zhang, sp. nov., wangi Chen and Zhang, sp. nov., wuyishanensis Chen and Zhang, sp. nov. A key to all species from southern China is provided. The Amiota fauna of southern China at the species-group level is compared with that of six geographic regions. The subgenus Amiota is assumed to have originated and produced many species-groups in the Oriental region of East Asia, and then the basdeni, alboguttata and rufescens species-groups might have spread to Europe and North-Central America throughout the Palearctic region of East Asia and both the apodemata, sinuata and nagatai species-groups to tropical regions of South-East Asia.

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Background: The emergence of agriculture about 10,000 years ago marks a dramatic change in human evolutionary history. The diet shift in agriculture societies might have a great impact on the genetic makeup of Neolithic human populations. The regionally restricted enrichment of the class I alcohol dehydrogenase sequence polymorphism (ADH1BArg47His) in southern China and the adjacent areas suggests Darwinian positive selection on this genetic locus during Neolithic time though the driving force is yet to be disclosed. Results: We studied a total of 38 populations (2,275 individuals) including Han Chinese, Tibetan and other ethnic populations across China. The geographic distribution of the ADH1B*47His allele in these populations indicates a clear east-to-west cline, and it is dominant in south-eastern populations but rare in Tibetan populations. The molecular dating suggests that the emergence of the ADH1B*47His allele occurred about 10,000 similar to 7,000 years ago. Conclusion: We present genetic evidence of selection on the ADH1BArg47His polymorphism caused by the emergence and expansion of rice domestication in East Asia. The geographic distribution of the ADH1B*47His allele in East Asia is consistent with the unearthed culture relic sites of rice domestication in China. The estimated origin time of ADH1B*47His allele in those populations coincides with the time of origin and expansion of Neolithic agriculture in southern China.

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By using 19 Y chromosome biallelic markers and 3 Y chromosome microsatellite markers, we analyzed the genetic structure of 31 indigenous Sino-Tibetan speaking populations (607 individuals) currently residing in East, Southeast, and South Asia. Our results showed that a T to C mutation at locus M122 is highly prevalent in almost all of the Sino-Tibetan populations, implying a strong genetic affinity among populations in the same language family. Furthermore, the extremely high frequency of H8, a haplotype derived from M122C, in the Sino-Tibetan speaking populations in the Himalayas including Tibet and northeast India indicated a strong bottleneck effect that occurred during a westward and then southward migration of the founding population of Tibeto-Burmans. We, therefore, postulate that the ancient people, who lived in the upper-middle Yellow River basin about 10,000 years ago and developed one of the earliest Neolithic cultures in East Asia, were the ancestors of modem Sino-Tibetan populations.

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The prehistoric peopling of East Asia by modern humans remains controversial with respect to early population migrations. Here, we present a systematic sampling and genetic screening of an East Asian-specific Y-chromosome haplogroup (O3-M122) in 2,332 individuals from diverse East Asian populations. Our results indicate that the O3-M122 lineage is dominant in East Asian populations, with an average frequency of 44.3%. The microsatellite data show that the O3-M122 haplotypes in southern East Asia are more diverse than those in northern East Asia, suggesting a southern origin of the O3-M122 mutation. It was estimated that the early northward migration of the O3-M122 lineages in East Asia occurred similar to 25,000-30,000 years ago, consistent with the fossil records of modern humans in East Asia.

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There are around 27 species of Amolops amphibian distributed in South-east of Asia. Seven antimicrobial peptides (AMPs) belonging to two different families were purified from skin of rufous-spotted torrent frog, Amolops loloensis, and designated brevinins

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The now-emerging mitochondrial DNA ( mtDNA) population genomics provides information for reconstructing a well-resolved mtDNA phylogeny and for discerning the phylogenetic status of the subcontinentally specific haplogroups. Although several major East Asian mtDNA haplogroups have been identified in studies elsewhere, some of the most basal haplogroups, as well as numerous minor subhaplogroups, were not yet determined or fully characterized. To fill the lacunae, we selected 48 mtDNAs from >2,000 samples across China for complete sequencing that cover virtually all ( sub) haplogroups discernible to date in East Asia. This East Asian mtDNA phylogeny can henceforth serve as a solid basis for phylogeographic analyses of mtDNAs, as well as for studies of mitochondrial diseases in East and Southeast Asia.

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While it has been widely suggested that freshwater fishes from East Asia invaded the western Palaearctic, details about this process are largely unknown. Here, using the cytochrome b gene, we evaluated the phylogenetic relationships of a small group of Eurasian primary freshwater fishes (Cobitidae), which are widely distributed and species rich in East Asia and Europe, with the purpose of inferring their invasion process of Europe from East Asia. Though phylogenetic relationships of cobitids were not well resolved, our analysis could identify three sister groups formed by the European and East Asian cobitids, which brought new insights into the biogeography of the genera Cobitis, Misgurnus, and Sabanejewia. The present results support the view that Asian cobitid fishes may have invaded Europe at least five times independently, and once reverse colonization of European cobitids to East Asia could also be found. Ancestral Sabanejewia might have been the first cobitids to cross Siberia and invade the EMZS (Euro-Mediterranean zoogeographic subregion) about 33.54 million years ago (MYA). One lineage of Cobitis and the ancestor of Misgurnus fossilis (Linnaeus) almost in the same time invaded the Europe, responding to 16.71 MYA and 16.59 MYA, respectively. Three different lineages of Cobitis were found to have invaded the EMZS from East Asia, and once reverse invasion to East Asia occurred to one subclade of European Cobitis. And our data also suggest that the diversity of East Asian cobitid fishes, especially of the genus Cobitis, is greatly underestimated.

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The family Cyprinidae is one of the largest families of fishes in the world and a well-known component of the East Asian freshwater fish fauna. However, the phylogenetic relationships among cyprinids are still poorly understood despite much effort paid on the cyprinid molecular phylogenetics. Original nucleotide sequence data of the nuclear recombination activating gene 2 were collected from 109 cyprinid species and four non-cyprinid cypriniform outgroup taxa and used to infer the cyprinid phylogenetic relationships and to estimate node divergence times. Phylogenetic reconstructions using maximum parsimony, maximum likelihood, and Bayesian analysis retrieved the same clades, only branching order within these clades varied slightly between trees. Although the morphological diversity is remarkable, the endemic cyprinid taxa in East Asia emerged as a monophyletic clade referred to as Xenocypridini. The monophyly for the subfamilies including Cyprininae and Leuciscinae, as well as the tribes including Labeonini, Gobionini, Acheilognathini, and Leuciscini, was also well resolved with high nodal support. Analysis of the RAG2 gene supported the following cyprinid molecular phylogeny: the Danioninae is the most basal subfamily within the family Cyprinidae and the Cyprininae is the sister group of the Leuciscinae. The divergence times were estimated for the nodes corresponding to the principal clades within the Cyprinidae. The family Cyprinidae appears to have originated in the mid-Eocene in Asia, with the cladogenic event of the key basal group Danioninae occurring in the early Oligocene (about 31-30 MYA), and the origins of the two subfamilies, Cyprininae and Leuciscinae, occurring in the mid-Oligocene (around 26 MYA). (c) 2006 Elsevier Inc. All rights reserved.

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Loaches of the genus Niwaella, family Cobitidae, are distributed only in East Asia. At present only in Japan and South Korea have fishes of the genus Niwaella been found. Herein we revise the genus Niwaella in China. Son and He ( 2001) transferred the species Cobitis laterimaculata to the genus Niwaella, but their specimens were not N. laterimaculata, but a new species, N. longibarba sp. n., collected from Cao'ejiang River, Huangzezhen, Chengxian County, Zhejiang Province. The new species is distinguished from N. laterimaculata by its colour pattern of a row of slightly large, and long, scattered dark brown vertical bars on the dorsolateral surface, two or three striations on the caudal fin, and long barbels and undeveloped mental lobes. In this paper we also describe another new species, N. xinjiangensis sp. n., collected from Xinjiang River, Guangfeng County, Jiangxi Province, May 1990, with diagnostic colour pattern of 17 - 20 large and long, dark brown vertical bars on the dorsolateral surface, a dark stripe or rounded black spots along the lateral midline and some blotches below the lateral midline; it is a large-sized species, with shorter barbels, and longer caudal peduncle. Thus five species of the genus Niwaella are known, three are endemic to eastern China and two are endemic to either Japan or South Korea.