倭蜂猴静止代谢率和体温调节的研究

通过研究倭蜂猴在不同环境温度下的静止代谢率和体温调节特征发现；倭蜂猴（Ｎｙｃｔｉｃｅｂｕｓ ｐｙｇｍａｅｃｕｓ）的ＲＭＲ为０．４９８±０．０３９６０２ｍｌ／ｈｒ．ｇ，仅为预期值的６３．７％；热中性区不明显，实测 下临界温度为３０℃；平均最低热传导为０． ０８０４±０． ００２１０２ｍｌ／ｈｒ． ｓ．℃；在室温下平均体温为３３． ８ ±０．１８℃；在冷压下体温变化较大，温调指数为０．５３５；在高温时主要以高体温和分泌唾液进行体温调节。显示典型热带原猴类动物热能代谢特征。     

基于线粒体D-loop区和Cyt b基因分析广西禾花鲤三个群体遗传结构

研究基于线粒体D-loop区和Cyt b基因部分序列, 分析了广西全州、融水、环江三地禾花鲤(Cyprinus carpio)的遗传结构。在3个群体中共鉴定到19种D-loop与Cyt b序列的组合单倍型, 总的单倍型多样性(H_d)和核苷酸多样性(π)分别为0.916±0.010和0.008±0.004, 禾花鲤线粒体DNA具有单倍型多样性高和核苷酸多样性低的特点。环江群体单倍型多样性最低, 但是核苷酸多样性却最高, 反映了环江群体存在最明显的谱系混杂。分子方差分析(AMOVA)显示遗传变异主要来源于群体内部(71.54%), 禾花鲤三个群体间有显著的遗传分化(F_st=0.285; P<0.01)。系统发育分析表明, 多数样本的线粒体单倍型属于华南鲤(C. carpio rubrefusus)类型, 同时三地禾花鲤中均检测到一定频率的西鲤(C. carpio carpio)或远东鲤(C. carpio haematopterus)类型的线粒体单倍型, 提示禾花鲤可能受到鲤养殖品种的杂交渐渗。研究初步揭示了广西禾花鲤的种质资源现状, 为禾花鲤这一地方特色“稻鱼共作”品种的选育和苗种管理提供了必要的依据。     

倭蜂猴粪便微生物苯酚羟化酶和邻苯二酚1,2-双加氧酶基因多样性研究

【目的】分析倭蜂猴粪便微生物中苯酚羟化酶(Phenol hydroxylase,PH)和邻苯二酚1,2-双加氧酶(Catechol 1,2-dioxygenase,C12O)的基因多样性。【方法】利用简并引物,以倭蜂猴粪便微生物宏基因组DNA为模板,通过PCR扩增,分别构建PH和C12O基因克隆文库,并对克隆进行测序分析。【结果】倭蜂猴粪便微生物来源的PH和C12O基因序列经BLAST比对分析,与GenBank中相应酶的序列一致性分别介于92%?100%和87%?100%。系统进化树分析表明PH基因序列与Neisseria、Burkholderia、Alcaligenes、Acinetobacter 4个属来源的PH序列相关;C12O基因序列全部与Acinetobacter来源的C12O序列相关。序列比对结果表明PH序列具有LmPH (Largest subunit of multicomponent PH)中高保守的两个DEXRH结构域;C12O序列具有能被Ag+和Hg2+抑制的位点(半胱氨酸)。【结论】倭蜂猴粪便微生物来源的PH为多组分PH,其降解苯酚的中间产物邻苯二酚可以被C12O通过邻位开环途径裂解。     

中国地鼠线粒体Cyt b基因测序及其分子进化

目的测定中国地鼠线粒体DNA细胞色素b基因部分序列,分析其分子系统进化关系。方法提取中国地鼠肝脏的总基因组DNA。设计合成特异引物进行PCR扩增,经检测进行测序。用Blast与GenBank中啮齿类其他常用实验动物的物种细胞色素b基因进行同源序列比较,分析其碱基组成及变异情况,并用邻接法、最大简约法、最小进化法构建了分子系统树,在分子水平上探讨中国地鼠和常用啮齿类实验动物的进化关系。结果获得了中国地鼠线粒体Cytb基因的部分序列,共936bp。结论中国地鼠和金黄地鼠的亲缘关系最近,与小鼠、大鼠存在的差异相对大,与豚鼠的亲缘关系最远,与传统的分类地位基本吻合。     

关于经典遗传学中的基因和分子遗传学中的基因

今天我想借这次全国基因会议的机会,讨论一下有关基因和位点这两个概念。 按照孟德尔-摩尔根的遗传学说,基因是决定遗传性状的一小段染色体,并且可以通过杂交实验决定它在整个染色体上的位置,称为位点(Locus)。     

基于16S rRNA和Cyt b基因序列的鰶亚科系统发育研究

对鰶亚科4属5种鱼类的线粒体基因组16S rRNA和Cyt b基因片段序列进行序列比较和系统发育关系分析。结果显示:5种鰶亚科鱼类的16S rRNA和Cy tb基因片段同源序列长度分别为525 bp和402 bp,序列联合后的序列总长度为927 bp,其中多态位点178个,简约信息位点123个。选取太平洋鲱Clupea pallasii和大西洋鲱C.harengus为外类群,采用邻接法(NJ)、最大简约法(MP)、最大似然法(ML)和贝叶斯法(BI)分别对2个基因片段序列进行了聚类分析,并联合2个基因片段利用邻接法、最大简约法和贝叶斯法进行分析。系统发育分析显示:斑鰶Konosirus punctatus与花鰶Clupanodon thriss亲缘关系最近,分布于美洲大陆的真鰶属Dorosoma鱼类与印度洋、太平洋分布的斑鰶属、花鰶属和海鰶属Nematalosa鱼类亲缘关系较远。     

云南中缅树鼩线粒体细胞色素b和D-loop区遗传多样性研究

对3个地方种群的49只样本的线粒体Cyt b基因全序列（1140 bp）及33只样本的控制区D-loop基因区段（745 bp）进行了序列测定。结果表明：Cyt b基因多态性位点有47个,其中单变异位点位点23个,简约信息位点24个。共定义了24个单倍型,其中种群间的共享单倍型有2个（8.33%）,其余均为某个种群所特有,单倍型多样度范围为0.80952（剑川种群）~0.91532（禄劝种群）,核苷酸多样度指数介于0.00326（禄劝种群）~0.00635（剑川种群）之间;D-loop基因多态性位点有18个,其中单变异位点8个,简约信息位点10个。共定义了16个单倍型,无种群间的共享单倍型,单倍型多样度范围为0.76615（禄劝种群）~0.93333（丽江种群）,核苷酸多样度指数介于0.00269（禄劝种群）~0.00583（丽江种群）之间。从各单倍型的TCS网络进化图显示横断山种群位于分支的末端,表现出中缅树鼩由南向北的扩散模式,支持＂岛屿起源＂假说。     

线粒体Cyt b基因与昆虫分子系统学研究

细胞色素b(cytochrorrle b,Cyt b)是线粒体13个蛋白质编码基因中结构和功能被研究得最为清楚的基因之一,该基因的进化速度适中,适合研究种内到种间甚至科间的系统发育关系,研究内容涉及种及种下阶元的分类鉴定、种上阶元的系统发育分析、种群的遗传变异和进化研究、分子进化研究等方面,本文对Cyt b基因的分子特点及其在昆虫系统学研究中的应用进行综述。     

Phylogeography of the West Indian manatee (Trichechus manatus): how many populations and how many taxa?

To resolve the population genetic structure and phylogeography of the West Indian manatee ( Trichechus manatus ), mitochondrial (mt) DNA control region sequences were compared among eight locations across the western Atlantic region. Fifteen haplotypes were identified among 86 individuals from Florida, Puerto Rico, the Dominican Republic, Mexico, Colombia, Venezuela, Guyana and Brazil. Despite the manatee's ability to move thousands of kilometres along continental margins, strong population separations between most locations were demonstrated with significant haplotype frequency shifts. These findings are consistent with tagging studies which indicate that stretches of open water and unsuitable coastal habitats constitute substantial barriers to gene flow and colonization. Low levels of genetic diversity within Florida and Brazilian samples might be explained by recent colonization into high latitudes or bottleneck effects. Three distinctive mtDNA lineages were observed in an intraspecific phylogeny of T. manatus , corresponding approximately to: (i) Florida and the West Indies; (ii) the Gulf of Mexico to the Caribbean rivers of South America; and (iii) the northeast Atlantic coast of South America. These lineages, which are not concordant with previous subspecies designations, are separated by sequence divergence estimates of d = 0.04–0.07, approximately the same level of divergence observed between T. manatus and the Amazonian manatee ( T. inunguis , n = 16). Three individuals from Guyana, identified as T. manatus , had mtDNA haplotypes which are affiliated with the endemic Amazon form T. inunguis . The three primary T. manatus lineages and the T. inunguis lineage may represent relatively deep phylogeographic partitions which have been bridged recently due to changes in habitat availability (after the Wisconsin glacial period, 10 000 BP ), natural colonization, and human-mediated transplantation.     

Molecular evidence for a recent demographic expansion in the puma (Puma concolor) (Mammalia,Felidae)

The puma is an iconic predator that ranges throughout the Americas, occupying diverse habitats. Previous phylogeographic analyses have revealed that it exhibits moderate levels of genetic structure across its range, with few of the classically recognized subspecies being supported as distinct demographic units. Moreover, most of the species’ molecular diversity was found to be in South America. To further investigate the phylogeographic structure and demographic history of pumas we analyzed mtDNA sequences from 186 individuals sampled throughout their range, with emphasis on South America. Our objectives were to refine the phylogeographic assessment within South America and to investigate the demographic history of pumas using a coalescent approach. Our results extend previous phylogeographic findings, reassessing the delimitation of historical population units in South America and demonstrating that this species experienced a considerable demographic expansion in the Holocene, ca. 8,000 years ago. Our analyses indicate that this expansion occurred in South America, prior to the hypothesized re-colonization of North America, which was therefore inferred to be even more recent. The estimated demographic history supports the interpretation that pumas suffered a severe demographic decline in the Late Pleistocene throughout their distribution, followed by population expansion and re-colonization of the range, initiating from South America.     

Biogeographic Predictors of Genetic Diversity in Populations of Eastern African Chimpanzees (Pan troglodytes schweinfurthi)

I collected mitochondrial DNA sequences—hypervariable region 1 of the control region—from 281 eastern chimpanzees in 19 geographically defined populations and calculated genetic diversity measures to test the hypothesis that populations inhabiting the reconstructed locations of Pleistocene forest refugia harbor higher genetic diversities than those of other populations. The hypothesis is only weakly supported. Population genetic diversity is not significantly correlated with geographic proximity to refugia, with the area of forest that the populations currently occupy, or with the degree of geographic isolation of the populations. However, the two populations displaying the consistently highest genetic diversities are located in refuge areas: Uganda's Rwenzori Mountains and the eastern Democratic Republic of Congo's Ituri Forest. These results, in combination with previously findings, imply that chimpanzees may have lived both in and out of refugia during periods when tropical forests were restricted to refugia. This interpretation is consistent with the notion of chimpanzees as an extraordinarily vagile species, capable of maintaining gene flow across habitat mosaics of forest, woodland, and savannah.     

Global population structure of the tope (Galeorhinus galeus) inferred by mitochondrial control region sequence data

In order to properly manage and conserve exploited shark species, detailed analyses of their population structure is needed. Global populations of Galeorhinus galeus are in decline due to the exploitation of the fishery over the past 80 years. Currently, the genetic structure of eastern Pacific populations of G. galeus is not known and recent observations in the northeastern Pacific suggest an increase in numbers. To evaluate gene flow among populations of G. galeus , 116 samples were collected and analysed from six geographically dispersed locations: Australia, North America, South Africa, South America (Argentina and Peru), and the UK. Analysis of 968 to 1006 bp of the 1068-bp mitochondrial control region revealed 38 unique haplotypes that were largely restricted to their collecting locality. Significant genetic structure was detected among populations (Φ_ST = 0.84; P  < 0.000001) and migration estimates were low ( Nm  = 0.05–0.97). Due to an apparent lack of migration, populations of G. galeus appear to be isolated from each other with little to no gene flow occurring among them. As a consequence of this isolation, increasing numbers of G. galeus in the northeastern Pacific can be best explained by local recruitment and not by input from geographically distant populations.     

线粒体DNA序列特点与昆虫系统学研究

昆虫线粒体DNA是昆虫分子系统学研究中应用最为广泛的遗传物质之一。线粒体DNA具有进化速率较核DNA快 ,遗传过程不发生基因重组、倒位、易位等突变 ,并且遵守严格的母系遗传方式等特点。本文概述了mtDNA中的rRNA、tRNA、蛋白编码基因和非编码区的一般属性 ,分析了它们在昆虫分子系统学研究中的应用价值 ,以及应用DNA序列数据来推导分类阶 (单 )元的系统发育关系时 ,基因或DNA片段选择的重要性