华南6水系与澜沧江-湄公河攀鲈线粒体ND2基因的遗传多样性分析

测定了中国华南6水系及澜沧江(云南勐腊)-湄公河流域(柬埔寨洞里萨湖)的125尾攀鲈(Anabas testudineus)线粒体部分ND2基因1 010 bp序列,分析发现39个变异位点和12个单倍型,总遗传多样性较低(h=0.369,π=0.003 8),推测可能经历过严重的瓶颈效应;中国攀鲈群体遗传多样性更低(h=0.282,π=0.000 4),处于边缘区的中国攀鲈群体是造成低遗传多样性的主要原因。在单倍型网络图中柬埔寨和中国攀鲈各自聚类,具有明显地理结构和谱系结构,推测地质运动和气候变化导致基因交流受阻所致。核苷酸错配图和中性检验表明中国群体经历过种群扩张,时间约为(5.94~4.13)万年前。华南水系群体间基因交流通畅,不存在明显分化;但与云南澜沧江群体间分化大而显著(FST=0.775,P0.01),AMOVA分析显示变异主要来自组群间(77.41%),推测二者分化时间约为(4.0~2.8)万年前,云南群体受末次冰期的影响,基因交流受阻而出现分化。中国群体和柬埔寨群体可作为2个管理单位进行保护;就中国群体而言,韩江水系群体遗传多样性最高,建议优先保护;澜沧江与华南水系间群体分化显著且遗传多样性极低,建议对澜沧江水系群体进行保护,以避免种质资源灭绝。     

建昌马mtDNA D-loop区遗传多样性及系统进化分析

试验旨在以线粒体DNA(mitochondrial DNA,mtDNA)为切入点,研究建昌马的母系遗传多样性与系统进化。从建昌马(n=39)血液中提取基因组DNA,用PCR方法扩增mtDNA D-loop区并直接测序,分析其高变区247 bp序列信息,统计mtDNA D-loop区的单倍型及变异位点,计算单倍型多样性(haplotype diversity,Hd)、核苷酸多样性(nucleotide diversity,Pi)和平均核苷酸变异数(average number of nucleotide differences,K)。构建包括建昌马在内的19个品种马的NJ系统进化树,计算各品种间的遗传距离。结果显示,试验获得了清晰的PCR扩增产物,并通过直接测序方法获得了约1200 bp的序列。39匹建昌马mtDNA D-loop区247 bp序列(其中1个样品缺失1 bp)的AT碱基含量为61.45%,属AT碱基对富集区,检测到33个多态性位点,共显示26种单倍型,其中4种为共享单倍型,且Hap7和Hap1为优势单倍型,单倍型多样性为0.947,核苷酸多样性为0.02399,平均核苷酸变异数为5.901,显示丰富的母系遗传多样性;NJ系统进化树显示,建昌马分布在A、C、D、E、F、G共6个支系中,约50%的样品分布在A支系,显示出复杂的母系起源;建昌马与关中马的遗传距离最小(0.021),其次是三河马、文山马、韩国车巨马(0.024),与韩国济州岛马遗传距离最大(0.032)。本研究结果表明,建昌马的mtDNA D-loop高变区遗传多样性丰富,具有多个母系起源,且A支系占有明显优势,与关中马、文山马可能有共同的母系起源。     

不同地理群体三疣梭子蟹mtDNA本底甲基化水平分析

利用重亚硫酸盐测序法,对适于三疣梭子蟹(Portunus trituberculatus)线粒体基因组甲基化分析的BSP(Bisulfite sequencing PCR)引物进行了筛选,在设计的21对引物中,获得了12对BSP引物。利用这12对引物分析了三疣梭子蟹海州湾群体(江苏连云港)和莱州湾群体(山东东营)线粒体基因组本底甲基化水平,结果表明:海州湾群体不存在甲基化现象,莱州湾群体发现了2个个体在ND2基因(NADH脱氢酶亚基2)位点存在甲基化现象;在存在甲基化的个体中,甲基化类型主要为CHG和CHH类型,还有少量Cp G类型。该研究结果说明,莱州湾群体和海州湾群体线粒体基因组本底水平上的甲基化特征存在一定差异,相关研究值得进一步深入探讨。     

二倍体和四倍体泥鳅线粒体ND-5/6基因多态性的PCR-RFLP分析

采用PCR-RFLP分析方法,对洞庭湖、武汉两地的二倍体和四倍体泥鳅线粒体DNAND-5/6基因多态性及4个群体遗传变异和遗传关系进行了研究。结果表明,120尾泥鳅mtDNAND-5/6扩增片段长度均为2.2kb;从13种限制性内切核酸酶中筛选出6种多态性内切酶(HaeⅢ、DraⅠ、RsaⅠ、TaqⅠ、HinfⅠ、MspⅠ),对扩增产物进行酶切,共检测到66种单倍型。泥鳅群体内单倍型多样性和核苷酸多样性分别为0.7679～0.9385和0.01041～0.03212;其中,洞庭湖二倍体核苷酸多样性最高(0.03212),武汉二倍体其次(0.02452),二倍体群体内核苷酸多样性高于四倍体。群体间的核苷酸多样性(π)大小为0.02588～0.04144,平均值为(0.031737±0.000005)。群体间的核苷酸歧化距离(δ)大小为0.00462～0.01617,平均值为(0.010659±0.000003);其中,武汉二倍体和四倍体之间的核苷酸歧化距离最大(0.01617),武汉四倍体和洞庭湖二倍体之间的核苷酸歧化距离最小(0.00462)。MonteCarlo模拟x2检验表明,4个群体间的单倍型频率存在极...     

竹荚鱼属鱼类线粒体DNA控制区结构及其系统发育分析

采用PCR产物直接测序法测定了2尾来自中国南海的日本竹煲鱼（Trachurus japonicus）线粒体DNA控制区基因全序列，并结合从GenBank中下载的8种竹笑鱼属相应序列，对竹煲鱼属控制区序列进行了结构分析，识别出终止序列区、中央区和保守序列区3个区域，并找到了2个与DNA复制终止相关的序列TAS和中央保守区的保守序列CSB—F、CSB—E和CSB—D，以及保守序列区的保守序列CSBl、CSB2和CSB3。以鳜（Sinipercachuatsi）作为外群，使用邻接法和最大简约法构建了9种竹荚鱼属的系统发育树。竹笑鱼属鱼类为单系类群，蓝竹煲鱼（rpicturatus）、智利竹笑鱼（zmurphyi）、太平洋竹笑鱼（zsymmetricus）、南非竹荚鱼（rcapensis）和竹荚鱼（rtrachurus）构成一支，地中海竹笑鱼（zmediterraneus）、青背竹笑鱼（zdeclivis）、日本竹荚鱼（rjaponicus）和新西兰竹荚鱼（rnovaezelandiae）为另一支；日本竹笑鱼未单独成一支，而是聚人青背竹笑鱼和新西兰竹笑鱼之间，初步猜测日本竹笑鱼和新西兰竹荚鱼为同种异名。     

根据mtDNA控制区序列分析野生唇 的种群遗传结构

为了掌握不同地理种群唇(鱼骨)(Hemibarbu labeo)的遗传多样性和遗传结构,探讨其亲缘地理演化过程,研究分析了乌苏里江、长江、黑龙江、鸭绿江和牡丹江5大水系,8个地理群体(n=42)的mtDNA控制区404 bp片段的变异,该片段共有26个变异位点,变异率为6.43%,平均核苷酸多样性为0.011 5.42尾样本共检测到18个单倍型,这8个地理群体是以HT1和HT2单倍型为中心向外辐射演化的.AMOVA分析结果表明,群体内变异为59.29%,同一水系群体间变异为23.50%,不同水系群体间变异为17.20%,以上变异均达到显著水平(P＜0.05),群体间配对FST分析结果表明,同一水系内有些群体间差异也达到了显著水平.聚类分析发现,最大简约法(MP)和最大似然率法(ML)结果基本一致,嘉荫群体(HRJY)和四川群体(YRSC)绝大部分个体被聚在一支,鸭绿江群体(YRLJ)聚在一支,这与单倍型网络的分析结果一致,以上结果表明唇(鱼骨)的遗传多样较为丰富,黑龙江流域的唇(鱼骨)保持了祖先单倍型,其他地理群体为黑龙江流域内群体向不同方向演化的结果,并且部分地理群体已经形成了特有的单倍型.     

对两个玉米雄性不育系的细胞质分类研究

本文从普通遗传学、植物病理学和分子生物学的水平对玉米雄花不育系—元徐cms—小黄和恩二激cms—大黄进行了综合性的分类研究。大田的育性反应表明，这两个不育系的育性恢复受一对显性基因控制。对花粉染色的观察发现F1可育花粉与败育花粉基本上呈1：1分离。用小斑病T小种接种，这两个不育系不表现专化感染。通过mtDNA的分析     

东亚4个黑山羊群体mtDNA D-环遗传多样性及其起源

为了研究地方山羊品种的起源与分化，了解其遗传背景，为山羊资源的合理利用提供基础资料，利用PCR产物直接测序法对3个中国黑山羊群体和1个韩国黑山羊群体共39个个体的mtDNA D-环部分序列进行了测定和分析。测定的序列经排列比对后选取441bp分析，发现了55个多态位点，单一多态位点11个，简约信息位点44个，确定了29种单倍型，单倍型多样度为0.984。构建系统发育树将29种单倍型分成了明显的3个分支，角猾羊聚入A分支。同时利用群体间的单倍型的错配分布和遗传距离分析了各群体的亲缘关系。结果表明：4个黑山羊群体遗传多样性丰富，至少拥有3个不同的母系起源，角猾羊是家山羊的一个母系祖先。     

Establishing Cytoplasmic Male Sterility in Brassica napus by Mitochondrial Recombination with B. tournefortii

Fusion experiments between B. napus and X-ray-treated B. tournefortii protoplasts were carried out to develop cytoplasmic male sterility (ems) in B. napus. From the regenerants, six lines containing male sterile plants were selected; five lines segregated for male sterility, but one line (25–143) was completely male-sterile from the beginning. Molecular analyses of mitochondrial (mt) and chloroplast (cp) DNA of B. napus, B. tournefortii, B. juncea and cms juncea indicated that the original cytoplasmic donor of the cms juncea-system in B. napus was a B. tournefortii form, while the B. napus genotype used for the fusion experiments had a B. campestris cytoplasm. By analysis (it regenerated plants, line 25–143 was identified as possessing mt-DNA recombined between B. campestris and B. tournefortii. with the major part derived from B. campestris. No differences were detected between epDNAs from H. campestris and from line 25—143. The other five lines were similar to B. campestris with all the probes used. The low frequency of sterile lines from the fusion experiments and the inheritance of the cms in segregating progenies are both discussed.     

Hatchery introgression blurs ancient hybridization between brown trout (Salmo trutta) lineages as indicated by complementary allozymes and mtDNA markers

Populations living on the periphery of a species range are subjected to intense habitat pressures that stress their vulnerability to threats. South Iberian brown trout (Salmo trutta) populations are located on the southwestern boundary of the species range in Europe. This region has been described as a contact zone between Atlantic and Mediterranean populations in other fish species, and allozyme data detected natural hybridization between native Atlantic and Mediterranean brown trout in this area. Nevertheless, native pattern of populations relationships are threatened by hybridization with exogenous hatchery fish. Allozyme data and complete mtDNA control region sequences were used to analyse the ongoing processes of human mediated hybridization between native and hatchery brown trout in this region. Estimates of the persistence of hatchery genes detected a high level of introgression in some of the sampled locations (hatchery ancestry more than 25% in GF-1, GF-2 and GF-3), but results differed from both kinds of markers. The low intrapopulation diversity (H_s = 0.051) indicated that genetic drift could explain discrepancies between markers. At individual level, the complementary use of both markers detected more hatchery origin fish than those detected by the use of a single technique. Based on these results, the importance of considering a large number of genetic markers to evaluate introgression accurately is emphasized. The ability of the current management policies to the protection and conservation of marginal populations that retain complex and special evolutionary histories such as those studied is also questioned.