The ADH1B Arg47His polymorphism in East Asian populations and expansion of rice domestication in history

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.

Biogeography and molecular phylogeny of the genus Schizothorax (Teleostei : Cyprinidae) in China inferred from cytochrome b sequences

Aim: To test a vicariant speciation hypothesis derived from geological evidence of large-scale changes in drainage patterns in the late Miocene that affected the drainages in the south-eastern Tibetan Plateau. Location: The Tibetan Plateau and adjacent areas. Methods: The cytochrome b DNA sequences of 30 species of the genus Schizothorax from nine different river systems were analysed. These DNA sequences were analysed using parsimony, maximum likelihood and Bayesian methods. The approximately unbiased and Shimodaira-Hasegawa tests were applied to evaluate the statistical significance of the shortest trees relative to alternative hypotheses. Dates of divergences between lineages were estimated using the nonparametric rate smoothing method, and confidence intervals of dates were obtained by parametric bootstrapping. Results: The phylogenetic relationships recovered from molecular data were inconsistent with traditional taxonomy, but apparently reflected geographical associations with rivers. Within the genus Schizothorax, we observed a divergence between the lineages from the Irrawaddy-Lhuit and Tsangpo-Parlung rivers, and tentatively dated this vicariant event back to the late Miocene (7.3-6.8 Ma). We also observed approximately simultaneous geographical splits within drainages of the south-eastern Tibetan Plateau, the Irrawaddy, the Yangtze and the Mekong-Salween rivers in the late Miocene (7.1-6.2 Ma). Main conclusions: Our molecular evidence tentatively highlights the importance of palaeoriver connections and the uplift of the Tibetan Plateau in understanding the evolution of the genus Schizothorax. Molecular estimates of divergence times allowed us to date these vicariant scenarios back to the late Miocene, which agrees with geological suggestions for the separation of these drainages caused by tectonic uplift in south-eastern Tibet. Our results indicated the substantial role of vicariant-based speciation in shaping the current distribution pattern of the genus Schizothorax.

滇南、滇东南黑长臂猿分布与数量及金平芭蕉河黑长臂猿栖息地选择与利用

长臂猿是现存最小的类人猿（俗称小猿），主要分布于东南亚的的热带雨林、季雨林及亚热带常绿阔叶林中，是典型的树栖灵长类动物。我国现有长臂猿3属5种，包括黑长臂猿(Nomascus concolor)、白颊长臂猿(N. leucogenys)、海南长臂猿(N. hainanus)、白掌长臂猿(Hylobates lar)和白眉长臂猿(Hoolock hoolock)。其中黑长臂猿是主要分布于我国云南省境内的一种长臂猿，在国外仅在越南北部和老挝西北部局部地区分布，越南北部的数量不足100只，老挝目前仅发现9群。 滇南、滇东南曾是黑长臂猿广泛分布的地区之一。为掌握该地区近年黑长臂猿分布及种群数量现状，从2003年7月～2004年12月，利用访问调查及利用鸣声定位法对该地区进行了调查。调查结果显示，在云南境内，近40 000 km2的范围内，黑长臂猿在红河以东可能已消失，而红河以西亦仅发现4～7个种群，且孤立分布于3个地区（金平芭蕉河2群6只，金平西隆山1－2群，绿春黄连山1～3群，总计不超过25只），而在江城牛倮河自然保护区、马关古林箐自然保护区、麻栗坡老君山自然保护区及屏边大围山自然保护区可能已绝迹。滇南、滇东南黑长臂猿分布区缩小及种群数量剧减，主要与栖息地丧失及过度捕猎有关。 在长臂猿数量与分布调查的基础上，我们于2004年底确定了以金平芭蕉河黑长臂猿的一个群体为研究对象进行行为生态观察。通过扫描与瞬时取样法记录，结合生境调查及物候监测，对其游走行为及生境利用格局进行了比较和分析，主要结论如下：⑴家域大小（活动范围）不是限制长臂猿日活动距离及活动时间的主要原因；⑵日活动距离及移动时间均与温度呈正相关；⑶食物资源分布及斑块丰富度一定程度上决定了长臂猿对栖息地选择与利用方式；⑷长臂猿对陡坡与沟谷利用强度较高，与其主要行为表现（如;过夜点、休息点、取食点选择）有关；⑸长臂猿过夜点选择与食物资源分布、群体间关系及鸣叫点选择无关，而可能与天气和安全性因素有关；⑹果实树分布对取食点、休息点选择作用明显，而物候变化及食物可得性可能是影响长臂猿对栖息地利用季节性变化的主要原因；⑺在一定程度上，人为干扰只是在短时间内改变了长臂猿的活动路线或时间，而对其总体的生境利用策略并没有太大影响。食物资源的分布及季节性变化在长臂猿的游走行为及生境利用中均起到了重要作用。

Potential refugium on the Qinghai-Tibet Plateau revealed by the chloroplast DNA phylogeography of the alpine species Metagentiana striata (Gentianaceae)

Metagentiana striata is an alpine annual herbaceous plant endemic to the east of the Qinghai-Tibet (Q-T) Plateau and adjacent areas. The phylogeography of M. striata was studied by sequencing the chloroplast DNA (cpDNA) trnS-trnG intergenic spacer. Ten haplotypes were identified from an investigation of 232 individuals of M. striata from 14 populations covering the entire geographical range of this species. The level of differentiation amongst populations was very high (G(ST) = 0.746; N-ST = 0.774) and a significant phylogeographical structure was observed (P < 0.05). An analysis of molecular variance found a high variation amongst populations (76%), with F-ST = 0.762 (highly significant, P < 0.001), indicating that little gene flow occurred amongst the different regions; this was explained by the isolation of populations by high mountains along the Q-T Plateau and adjacent areas (N-m = 0.156). Only one ancestral haplotype (A) was common and widespread throughout the distributional range of M. striata. The populations of the Hengduan Mountains region of the south-eastern Q-T Plateau showed high diversity and uniqueness of haplotypes. It is suggested that this region was the potential refugium of M. striata during the Quaternary glaciation, and that interglacial and postglacial range expansion occurred from this refugium. This scenario was in good agreement with the results of nested clade analysis, which inferred that the current spatial distribution of cpDNA haplotypes and populations resulted from range expansion, together with past allopatric fragmentation events. (c) 2008 The Linnean Society of London.