大螟不同地理种群COⅡ基因序列分析

本研究通过对我国大螟Sesamia inferens 9个地理种群的线粒体DNACOII基因的测序,运用软件DNAStar的MegAlign程序分析了大螟不同地理种群之间的COII序列的遗传分歧及相似性;同时运用Mega 3.0软件建立其系统发育关系。结果表明,COII基因在大螟中进化速度较快,不同种群之间已产生较大的差异,序列相似性分析显示大螟种群间序列相似性最低仅为90.7（海南和江西种群）,进化分歧矩阵同时也显示差异最大为0.102（云南和江西种群）。此外,以与大螟同属的非洲大螟及螟蛾科的台湾稻螟为外群进行比较显示,COII基因在属内种间差异明显,遗传相似性为87.7-91.8,进化分歧为0.088-0.137;与台湾稻螟的差异最大,相似性仅为82.2-85.8,进化分歧为0.159-0.202。进化树显示,大螟贵州的丹寨种群、沿河种群和福建的福州种群聚为一个分支,江苏扬州种群和江西新余种群聚为一支,安徽的阜阳种群和芜湖种群关系最近,说明不同地理种群的大螟的遗传分化与地理距离之间具有一定的相关性。     

大螟不同地理种群COII基因序列分析

本研究通过对我国大螟Sesamia inferens 9个地理种群的线粒体DNA COII基因的测序,运用软件DNAStar的MegAlign程序分析了大螟不同地理种群之间的COII序列的遗传分歧及相似性;同时运用Mega 3.0软件建立其系统发育关系.结果表明,COII基因在大螟中进化速度较快,不同种群之间已产生较大的差异,序列相似性分析显示大螟种群间序列相似性最低仅为90.7(海南和江西种群),进化分歧矩阵同时也显示差异最大为0.102(云南和江西种群).此外,以与大螟同属的非洲大螟及螟蛾科的台湾稻螟为外群进行比较显示,COII基因在属内种间差异明显,遗传相似性为87.7～91.8,进化分歧为0.088～0.137;与台湾稻螟的差异最大,相似性仅为82.2～85.8,进化分歧为0.159～0.202.进化树显示,大螟贵州的丹寨种群、沿河种群和福建的福州种群聚为一个分支,江苏扬州种群和江西新余种群聚为一支,安徽的阜阳种群和芜湖种群关系最近,说明不同地理种群的大螟的遗传分化与地理距离之间具有一定的相关性.     

中国东北地区亚洲玉米螟遗传多样性及寄主专化性分析

【目的】为了明确中国东北地区亚洲玉米螟Ostrinia furnacalis不同地理种群、不同田间寄主种群间的遗传分化程度和基因流水平,了解不同种群间是否产生寄主专化性和遗传结构的差异。【方法】采用双向测序法测定了采自中国东北3种主要寄主植物(玉米Zea mays、高粱Sorghum bicolor和谷子Setaria italica)上的23个地理种群400头亚洲玉米螟个体的线粒体细胞色素氧化酶亚基I (COI)基因的1 034 bp序列;利用DnaSP 5. 0和Arlequin3. 5. 1. 2等软件对亚洲玉米螟不同寄主种群以及不同地理种群间的遗传多样性、基因流水平、系统进化发育和分子变异进行分析。【结果】共获得400条长度为1 034 bp的亚洲玉米螟线粒体COI基因序列,包含60个单倍型。亚洲玉米螟总群体的单倍型多样度(Hd)为0. 793±0. 01,不同地理种群间的单倍型多样度范围在0~0. 916±0. 041之间。总基因交流水平较高(Nm=2. 67),总的群体Fst为0. 1579,不同地理种群的Fst范围在-0. 046~0. 627之间。总种群的Tajima’s D为-1. 73602,检验结果不显著,说明中国东北地区亚洲玉米螟未曾在近期经历种群扩张,群体大小稳定。AMOVA分子变异分析结果表明,不同地理种群间的遗传分化较大(Fst=0. 16236,P 0. 0001),83. 76%遗传变异主要来自种群内部,而种群间的遗传变异仅为16. 24%,不同寄主种群间的遗传分化(Fct=0. 01568,P 0. 05)很小,遗传变异仅占1. 57%,说明亚洲玉米螟的遗传分化主要来自种群内部,而非其地理种群间或寄主种群间。各寄主种群的单倍型在系统发育树上和中介网络图上散布在不同种群中,缺乏明显的地理分布和寄主分布格局。【结论】亚洲玉米螟较强的迁飞能力(或随气流进行远距离传播),使各种群间的基因交流未受到地理距离的影响,遗传距离与地理距离之间没有显著相关性。虽其寄主范围较广,但取食不同寄主植物的亚洲玉米螟种群间基因交流频繁,以玉米、高粱和谷子为寄主的种群尚未产生寄主专化性和种群遗传结构的差异。     

基于COI基因的华南地区柑橘木虱系统发育研究

柑橘木虱Diaphorina citri是重要的柑橘害虫,其传播的黄龙病对华南地区柑橘产业造成严重危害。为了解华南地区柑橘木虱不同地理种群间的遗传多样性和进化关系,测定该地区5个地理种群线粒体COI基因900 bp序列,对不同地理种群柑橘木虱遗传距离和系统发育进行分析。结果表明,5个地理种群柑橘木虱间的遗传距离小(0.0%~0.2%)。其中,广州种群和湛江种群的柑橘木虱之间的遗传距离,以及南宁种群、桂林种群和厦门种群的柑橘木虱之间的遗传距离均为0,序列间的相似度极高。基于COI基因系统发育分析显示,位于中国的5个柑橘木虱地理种群之间分化程度较低,与国外其他地区21个种群相比,各种群间的同源性与地理距离无显著相关性。     

资源昆虫角倍蚜遗传多样性及遗传分化的AFLP分析

本研究采用AFLP分子标记技术对资源昆虫角倍蚜Schlechtendalia chinensis 6个种群共102个个体的样本进行遗传多样性分析, 探讨角倍蚜主要分布区不同种群之间的遗传分化及其变异程度, 为合理利用和保护该经济昆虫提供分子方面的证据。结果表明: 经过摸索实验筛选出的4对选择性扩增引物共扩增条带126条, 多态性条带比例为100%, 种群多态性位点比例介于23.81%～66.67%之间; Nei's基因多样性指数介于0.0942～0.1980之间; Shannon's多样性数介于0.1381～0.3027之间; AMOVA分析显示57.99%的变异来源于种群内, 42.41%的变异来源于种群间（P<0.01）; 总群体的Fst值为0.4242; NJ聚类树显示角倍蚜6个种群共形成两个大的聚类簇, 阳雀、丹寨和汉中种群聚为一支, 安县、竹山和龙胜3个种群聚为另一支。总体上, 角倍蚜种内的遗传多样性较低, 而种群间的遗传分化较大, 遗传距离与地理距离之间没有显著的相关关系（P>0.05）。     

基于mtCOII基因对山东省越冬代亚洲玉米螟不同种群的遗传结构分析

亚洲玉米螟Ostrinia furnacalis (Guenée)是我国重要农业害虫.为了全面揭示亚洲玉米螟遗传分化以及山东省亚洲玉米螟不同种群的遗传结构,对山东省越冬代亚洲玉米螟不同种群mtCOⅡ基因序列与来自GenBank的相关序列进行了遗传结构分析,并建立了鉴别不同遗传支系的PCR-RFLP方法.基于对340条mtCOⅡ序列的分析结果表明:所有样本共获得62个单倍型,其中单倍型17(H17)广泛分布于各种群之间,有6个单倍体型为山东种群所特有;亚洲玉米螟分化为2个遗传支系(支系Ⅰ与支系Ⅱ);2个遗传支系均在山东省发现,但以支系Ⅰ为主;亚洲玉米螟各单倍体型散布于山东省各地理种群中,缺乏明显的地理分布格局.山东亚洲玉米螟总体的单倍体型多样性指数Hd为0.695,种群内单倍型多样性指数在0.333-0.889之间;总体的核酸多样性指数π为0.00424,种群内核酸多样性指数在0.00061-0.00809之间.总群体的固定系数Fst为0.79421.AMOVA分析结果表明山东亚洲玉米螟的遗传分化主要来自于2个支系之间(79.42％).构建的亚洲玉米螟2个支系鉴别方法为其生物学与生态学的进一步研究奠定了基础.     

海南岛4条河流李氏吻虾虎鱼的群体遗传结构分析

海南岛众多独立入海的河流形成天然的生物地理屏障，造就了海南丰富的淡水鱼类资源。李氏吻虾虎鱼〔Rhinogobius leavelli （Herre，1935）〕因利用价值低而未被人工大量养殖驯化，可作为评估鱼类遗传多样性的理想物种。本文基于COX1和D-loop分子标记，分析了海南岛南渡江、珠碧江、三亚河和陵水河等4条河流中李氏吻虾虎鱼的种群遗传结构。遗传多样性分析显示，4条水系中43尾李氏吻虾虎鱼COX1、D-loop及联合基因中分别检测出8、14、22个变异位点和6、7、8个单倍型，平均单倍型多样性和核苷酸多样性分别是0.617、0.647、0.649和0.003 9、0.009 4、0.006 3，其中三亚河与陵水河种群的遗传多样性均较高。系统发育树结果均显示，李氏吻虾虎鱼4个水系的5个地理种群聚类为2个进化分支，其中三亚河与陵水河种群聚为一支，南渡江、珠碧江种群聚为一支。遗传距离分子方差分析显示，李氏吻虾虎鱼群体的遗传变异主要来自种群间。上述结果表明，海南岛李氏吻虾虎鱼表现出显著的遗传分化，遗传多样性水平较高，可能因不同水系的隔离效应和李氏吻虾虎鱼较弱的迁移能力导致其种群间的遗传分化，本文为海南岛河流生态系统中鱼类种质资源多样性的研究提供遗传学参考。     

菱角萤叶甲不同地理种群及近缘种rDNA-ITS1基因序列初步分析

通过对我国菱角萤叶甲Galerucella birmanica Jacoby 6个地理种群和褐背小萤叶甲Galerucella grisescens Joannis扬州种群的核糖体DNA第1内转录间隔区（rDNA-ITS1）的测序,并调用GenBank中该属其它4种昆虫的同源序列,运用软件DNAStar的MegAlign程序对小萤叶甲属种间、同种不同地理种群之间的ITS1序列的遗传分歧及相似性进行了分析,运用Mega3.0软件建立系统发育关系.序列分析结果表明,rDNA-ITS1基因在小萤叶甲属昆虫中进化速度较快,种下具有一定的差异,种间差异明显.该基因适合小萤叶甲属种间和种下的分类鉴定研究.进化树显示,菱角萤叶甲泰安种群和扬州种群形成一个分支,益阳种群和新余种群形成一个分支,苏州种群和上海青浦种群形成一个分支,这一现象说明6个地理种群的菱角萤叶甲分化与寄主和地理距离之间具有较高的相关性.     

亚洲小车蝗不同地理种群遗传多样性的等位酶分析

采用等位酶电泳技术对亚洲小车蝗8个地理种群遗传多样性和遗传分化进行了研究,并对8种等位酶系统:苹果酸脱氢酶(MDH)、苹果酸酶(ME)、乙醇脱氢酶(ADH)、谷氨酸脱氢酶(GDH)、谷氨酸-草酰乙酸转氨酶(GOT)、异柠檬酸脱氢酶(IDH)、腺苷酸激酶(AK)和己糖激酶(HK)进行聚丙烯酰胺凝胶电泳分析。结果表明:在亚洲小车蝗8个地理种群中共检测到14个基因位点,其中7个位点为多态位点,检测到25个等位基因;种群总体水平多态位点比率P=42.86%,平均有效基因数A=1.786,平均期望杂合度He=0.072,种群平均遗传距离为0.069～0.235。聚类分析表明,遗传距离与地理距离存在一定相关性。亚洲小车蝗8个种群的遗传分化系数Fst=0.086,基因流Nm=3.142,表明亚洲小车蝗种群间有一定程度的遗传分化及基因交流。     

基于COⅠ基因探讨北京及其周边地区跳钩虾种群遗传结构

跳钩虾Platorchestia japonica栖息于湖泊、河流岸边,是重要的环境指示生物。本研究以线粒体COⅠ基因片段为分子标记,对北京及其周边地区22个采样点的128个样本进行种群遗传多样性和遗传结构研究。结果显示,623 bp的COⅠ基因序列中有567个保守位点、56个变异位点和38个简约信息位点。128个样本检测到43个单倍型,单倍型多样性为0.938,核苷酸多样性为0.011 72。最大似然法和贝叶斯法构建的系统发育树以及单倍型网络图表明,研究区域跳钩虾没有明显的地理种群结构,但所有单倍型形成2个遗传进化支。分子变异分析结果证实,跳钩虾2个进化支间的遗传变异显著高于进化支内的,进化支间固定系数为0.852 19,表明2个进化支遗传分化明显。本研究为进一步研究中国区域跳钩虾的遗传结构提供了有意义的基础数据。     

针叶小爪螨板栗和杉木种群间的遗传分化和杂交试验

为明确针叶小爪螨Oligonychus ununguis（Jacobi）山东板栗种群和浙江杉木种群的遗传分化程度,本研究对其基因序列（线粒体COⅠ和核糖体ITS2）进行了比较,并通过杂交试验测定了两者间的杂交亲和性.采用PCR产物直接测序法获得410 bp的COⅠ片段及469 bp（板栗种群）和513 bp（杉木种群）的完整ITS2序列,COⅠ及ITS2序列在两种群间的差异分别为10.5%~10.8%和15.2%~15.7%.杂交试验表明两种群间存在完全的生殖隔离.根据两者间的序列差异和杂交结果,初步认为山东板栗和浙江杉木上的小爪螨可能是两个不同的种     

Phylogenetic analysis of ecological and morphological diversification in Hispaniolan trunk-ground anoles (Anolis cybotes group)

Abstract Anolis lizards in the Greater Antilles partition the structural microhabitats available at a given site into four to six distinct categories. Most microhabitat specialists, or ecomorphs, have evolved only once on each island, yet closely related species of the same ecomorph occur in different geographic macrohabitats across the island. The extent to which closely related species of the same ecomorph have diverged to adapt to different geographic macro-habitats is largely undocumented. On the island of Hispaniola, members of the Anolis cybotes species group belong to the trunk-ground ecomorph category. Despite evolutionary stability of their trunk-ground microhabitat, populations of the A. cybotes group have undergone an evolutionary radiation associated with geographically distinct macrohabitats. A combined phylogeographic and morphometric study of this group reveals a strong association between macrohabitat type and morphology independent of phylogeny. This association results from long-term morphological evolutionary stasis in populations associated with mesic-forest environments ( A. c. cybotes and A. marcanoi ) and predictable morphometric changes associated with entry into new macrohabitat types (i.e., xeric forests, high-altitude pine forest, rock outcrops). Phylogeographic analysis of 73 new mitochondrial DNA sequences (1921 aligned sites) sampled from 68 geographic populations representing 12 recognized species and subspecies diagnoses 16 allopatric or parapatric groupings of populations differing from each other by 5–18% sequence divergence. At least some of these groupings appear to have attained species-level divergence from others. Evolutionary specialization to different macrohabitat types may be a major factor in the evolutionary diversification of Greater Antillean anoles.     

Indo-Pacific population structure and evolutionary history of the coconut crab Birgus latro

Mitochondrial DNA variation was used to examine population structure in a widespread, marine-dispersed species, Birgus latro . Crabs were collected from eight locations throughout the species' Indo-Pacific distribution. Purified mtDNA from 160 individuals was cut with five restriction enzymes, revealing high haplotype diversity (0.96) and moderate nucleotide diversity (0.75%). Island populations from the Indian Ocean (Christmas I.) and Pacific Ocean were significantly different ( G _ST= 0.37) and had distinct mtDNA lineages with a net sequence divergence of 1.4%. Pacific island populations had diverged in a manner consistent with isolation by distance, with only the most peripheral populations being significantly different. The results for mtDNA are largely concordant with those from allozymes, although estimates of gene flow between the Indian and Pacific Oceans were much lower when based on mtDNA. The mtDNA phylogeny also permitted a deeper examination of the evolutionary and demographic history of Birgus latro . Long-term separation of populations is evident in the complete phylogenetic subdivision of mtDNA lineages between the Indian and Pacific Ocean populations sampled. The starlike phylogeny of alleles from the Pacific suggests a rapid population expansion in the Pacific during the Pleistocene. Including information about allele phylogeny, as well as distribution and frequency, obscured contemporary population structure, but provided unique insights into the evolutionary history of the species.     

亚洲玉米螟幼虫体内保幼激素二醇激酶cDNA片段克隆与序列分析

为研究亚洲玉米螟Ostrinia furnacalis(Guenée)幼虫体内保幼激素二醇激酶(JHDK)表达调控的分子机理,根据不同昆虫保幼激素二醇激酶基因序列的保守区域,设计合成简并引物,采用RT-PCR技术从亚洲玉米螟5龄幼虫中扩增出一段cDNA片段,大小为189bp,编码63个氨基酸,预测分子量为6.78ku,理论等电点pI值为4.57。该基因序列中含有保守的GTP结合蛋白特征指纹基序∑3和∑1。BlastP分析结果表明:该片段氨基酸序列与烟草天蛾JHDK氨基酸序列的一致性最高,为69%;与家蚕和小菜蛾JHDK氨基酸序列的一致性分别为55%和52%。构建系统发育树分析了3种鳞翅目昆虫JHDK进化关系,结果显示:亚洲玉米螟cDNA片段氨基酸序列与家蚕JHDK的亲缘关系最近,与小菜蛾JHDK的亲缘关系最远。半定量PCR结果表明:JHDK基因在中肠中表达量最高,随着5龄幼虫的发育,JHDK基因在血细胞、脂肪体和体壁组织中表达量有下降趋势,但在中肠组织中表达量明显增强。     

Stickleback fishes: Bridging the gap between population biology and paleobiology

Integration of evolutionary mechanisms and phylogeny requires study of phenotypes that change in the fossil record and continue to evolve in extant populations. Pelvic reduction in the three-spined stickle-back has evolved rapidly in a Miocene fossil assemblage and in numerous extant isolated lake populations throughout its distribution. Although pelvic reduction is caused by selection, expression of reduced pelvic phenotypes is constrained by development and other factors. However, lineages with pelvis reduction rapidly go extinct while lineages that retain the fully formed pelvic girdle tend to persist. Existence of pelvic reduction since the Miocene has depended on an equilibrium between divergence and extinction. The phylogenetic topology resulting from this process differs greatly from the conventional view of evolutionary history, and could only be recognized by analysis of both extant populations and fossil material. If this phylogenetic topology is common, it may help to account for the different perceptions that population biologists and paleobiologists have of evolutionary tempo.     

Local adaptation in the rock pocket mouse (Chaetodipus intermedius): natural selection and phylogenetic history of populations

Elucidating the causes of population divergence is a central goal of evolutionary biology. Rock pocket mice, Chaeotdipus intermedius, are an ideal system in which to study intraspecific phenotypic divergence because of the extensive color variation observed within this species. Here, we investigate whether phenotypic variation in color is correlated with local environmental conditions or with phylogenetic history. First, we quantified variation in pelage color (n=107 mice) and habitat color (n=51 rocks) using a spectrophotometer, and showed that there was a correlation between pelage color and habitat color across 14 sampled populations (R2=0.43). Analyses of mtDNA sequences from these same individuals revealed strong population structure in this species across its range, where most variation (63%) was partitioned between five geographic regions. Using Mantel tests, we show that there is no correlation between color variation and mtDNA phylogeny, suggesting that pelage coloration has evolved rapidly. At a finer geographical scale, high levels of gene flow between neighboring melanic and light populations suggest the selection acting on color must be quite strong to maintain habitat-specific phenotypic distributions. Finally, we raise the possibility that, in some cases, migration between populations of pocket mice inhabiting different lava flows may be responsible for similar melanic phenotypes in different populations. Together, the results suggest that color variation can evolve very rapidly over small geographic scales and that gene flow can both hinder and promote local adaptation.     

Malate dehydrogenase: a useful phylogenetic marker for the genus Aeromonas

The reconstruction of correct genealogies among biological entities, the estimation of the divergence time between organisms or the study of the different events that occur along evolutionary lineages are not always based on suitable genes. For reliable results, it is necessary to look at full-length sequences of genes under stabilizing selection (neutral or purifying) and behaving as good molecular clocks. In bacteria it has been proved that the malate dehydrogenase gene (mdh) can be used to determine the inter- and intraspecies divergence, and hence this gene constitutes a potential marker for phylogeny and bacterial population genetics. We have sequenced the full-length mdh gene in 36 type and reference strains of Aeromonas. The species grouping obtained in the phylogenetic tree derived from mdh sequences was in agreement with that currently accepted for the genus Aeromonas. The maximum likelihood models applied to our sequences indicated that the mdh gene is highly conserved among the Aeromonas species and the main evolutionary force acting on it is purifying selection. Only two sites under potential diversifying selection were identified (T 108 and S 193). In order to determine if these two residues could have an influence on the MDH structure, we mapped them in a three-dimensional model constructed from the sequence of A. hydrophila using the human mitochondrial MDH as a template. The presence of purifying selection together with the linear relationship between substitutions and gene divergence makes the mdh an excellent candidate gene for a phylogeny of Aeromonas and probably for other bacterial groups.     

Evolutionary divergence in directions of high phenotypic variance in the ostracode genus poseidonamicus

Trait variation and covariation are understood to influence the response of populations to natural selection on generational time scales, but their role, if any, in shaping long-term macroevolutionary divergence is still unclear. The present study uses the rich fossil record of the ostracode genus Poseidonamicus to reconstruct in great detail the evolutionary history of a set of landmark-based morphometric characters. This reconstruction included two kinds of evolutionary inferences: ancestor-descendant transitions among populations repeatedly sampled at the same location and divergence between lineages measured as independent contrasts on a phylogeny. This reconstructed history was then used to test if evolutionary changes were concentrated in directions (traits or combinations of traits) with high phenotypic variance. Two different statistics of association between evolution and variation tested the null hypothesis that evolutionary changes occur in random directions with respect to trait variability. The first of these measured the similarity between the directions of evolutionary change and the axis of maximum variance, and the second measured the degree to which evolutionary changes were concentrated in directions of high phenotypic variation. Randomization tests indicated that both kinds of evolutionary inferences (ancestor-descendant and phylogenetic contrasts) occurred preferentially in directions of high phenotypic variance (and close to the axis of maximal variation), suggesting that within-population variation can structure long-term divergence. This effect decayed after a few million years, but at least for one metric, never disappeared completely. These results are consistent with Schluter's genetic constraints model in which evolutionary trajectories on adaptive landscapes are deflected by variation within and covariation among traits.