利用线粒体D-loop区分析家鸭品种遗传多态性与系统进化

通过线粒体DNA控制区的结构和多态性来研究我国家鸭的遗传多态性与系统进化。利用DNA测序技术测定了我国9个家鸭品种106个个体线粒体DNA控制区多变序列。序列分析结果显示:A、C、T、G碱基的平均含量分别为25.6%、33.3%、15.2%和25.9%。检测到34个变异位点,约占分析位点总数的5.1%,有转换、颠换、插入/缺失4种类型的变异。确定了31种单倍型,其中单倍型A7为家鸭的主体单倍型,品种之间有9种共享单倍型。9个家鸭品种单倍型多样度(Hd)平均为0.798,核苷酸多样度(Pi)平均为0.28%,单倍型多样度在荆江麻鸭中最高,其次是攸县麻鸭和恩施麻鸭,在文登黑鸭中最低。9个品种家鸭之间双参数距离范围为0.001 3~0.004 4。31个家鸭单倍型序列的系统发生分析表明,9个家鸭品种只有1个母系起源,没有发现东亚斑嘴鸭对9个家鸭品种起源有贡献的证据。     

新型甜菜细胞质雄性不育系的获得及遗传学鉴定

以野生甜菜Ｂ．ｐａｔｕｌａＡｉｔ作母本，叶用甜菜Ｂ．ｃｉｅｌａＬ．和糖甜菜Ｂ．ｖｕｌｇａｒｉｓＬ．作父本，通过３种间杂交，获得了一种新型甜菜细胞质雄性不育系．细胞学观察表明，该不育系表现出特异的花粉败育特性。以通用的Ｏｗｅｎ型不育系作对照，通过线粒体ＤＭＡ的ＲＦＬＰ分析，结果显示两类不育系的线粒体基因组织结构具有明显差异，从分子生物学角度证实了所获得的不育系为不同于Ｏｗｅｎ型的新型不育系。     

Genetic Diversity of Lueyang Black-bone Chicken Based on Mitochondrial DNA D-loop Region Sequence

This study was aimed to assess mitochondrial DNA D-loop sequence diversity and origin of Lueyang Black-bone chicken.The mtDNA D-loop sequence of 30 individuals from Lueyang Black-bone chicken were amplified by PCR and subsequently sequenced.The mtDNA D-loop sequence of other chicken were collected from GenBank and used as reference sequences to analyze the diversity and origin of Lueyang Black-bone chicken.The results revealed that the average values of base composition of A,C,G and T in mtDNA D-loop the sequence of Lueyang Black-bone chicken were 26.6%,26.6%,13.4% and 33.4%,respectively.26 nucleotide polymorphic sites were transition.The average nucleotide diversity (Pi) of the sites and haplotype diversity (Hd) were 0.00705 and 1.000,and the value of Tajima's D was -0.47272.Phylogenetic tree showed that samples were clusted in 4 clades. In the research, it could be concluded that the genetic diversity was relatively rich and wealthy and there were 4 maternal origins to Lueyang Black-bone chicken population.     

4种河蓝蛤线粒体COI和16S rRNA基因序列的种间遗传分析

对光滑河蓝蛤Potamocorbula laevis、黑龙江河蓝蛤P.amurensis、焦河蓝蛤P.ustulata、红肉河蓝蛤P.rubromuscula4个野生种共40个个体的线粒体COI和16SrRNA基因片段进行了扩增和测序,经过筛选和剪切,得到长度为650bp和450bp的片段。序列分析显示,序列的碱基组成中G+C含量较低,16SrRNA基因种间和种内的变异较低,COI基因片段种内和种间的变异较高。以沙海螂Mya arenaria为外群,用MEGA 4.0软件中的NJ法构建了系统进化树,通过遗传距离和系统进化树可以看出,4种河蓝蛤未能达到不同种之间显著的遗传分化。     

西藏牦牛mtDNA ND6遗传多样性及系统进化分析

为从分子水平上探究西藏牦牛的序列多态性、遗传多态性及其系统进化关系,对西藏15个牦牛类群150个个体的mtDNA ND6基因全序列进行了测定,确定了多态位点和单倍型数目,计算了单倍型多样性(Hd)和核苷酸多样性(Pi),并构建了分子聚类关系图和单倍型系统发育树。结果表明:西藏牦牛mtDNA ND6基因全序列长度均为528bp,T、C、A和G 4种碱基的平均比例分别为42.2%、7.6%、20.9%、29.3%,存在一定的碱基组成偏倚性。序列变异中存在转换、颠换2种核苷酸变异类型,其中转换37次,颠换2次,表现出较强的转换偏倚性。根据序列间核苷酸变异共确定7种单倍型,其中Hap_1为西藏牦牛类群的主流单倍型,其余6种单倍型为部分类群所特有。平均单倍型多样性(Hd)、平均核苷酸多样性(Pi)分别为0.2978、0.00191,揭示西藏牦牛mtDNA ND6遗传多样性较贫乏。根据遗传距离构建了分子聚类关系图,表明西藏15个牦牛类群可分为2大类;根据7种单倍型序列构建了单倍型系统发育树,表明西藏牦牛存在2个母系起源。     

郏县红牛mtDNA D-loop区遗传多样性与母系起源研究

［目的］探究郏县红牛的mtDNA D-loop遗传多样性与母系起源。［方法］采用生物信息学方法。［结果］在46头郏县红牛mtDNA D-loop区全序列共检测到60个变异位点,定义20种mtDNA D-loop单倍型,平均单倍型多样度(Hd)为0.8530,平均核苷酸多样度(Pi)为0.0254,表明郏县红牛有丰富的母系遗传多样性。构建的IQ系统发育树表明郏县红牛具有瘤牛和普通牛两个母系支系。［结论］郏县红牛具有丰富的母系遗传多样性,有普通牛和瘤牛两个母系起源。     

太湖鲢鱼mtDNA D-loop区遗传多样性

采用聚合酶链式反应(PCR)技术对太湖鲢鱼的mtDNA D-loop序列进行扩增,获得了大小约为500 bp的扩增产物。PCR产物经纯化后克隆到pMD19-T Vector进行序列鉴定测序,得到了520 bp的核苷酸片段(除去引物及部分端部序列)。用CLUSTAL X(1.83)软件进行排序比较,在30个个体中,共检测到52个变异位点,包括1个碱基缺失、36个转换位点、15个颠换位点及1个转换与颠换同时存在的位点。运用MEGA软件计算出不同个体间的遗传距离,并据此构建了NJ系统树。用DNASP软件计算出的多态位点数(S)为52、核苷酸多样性(Pi)和平均核苷酸差异数(k)分别为1.24%±0.35%和6.368。研究结果表明,太湖鲢鱼的mtDNA D-loop个体序列变异程度较大,遗传多样性较为丰富。     

基于细胞色素b基因序列分析的华南居氏银鱼遗传多样性研究

测定了广东虎门、广西合浦和广西钦州3个群体45 ind居氏银鱼(Salanx cuvieri)线粒体DNA细胞色素b基因1 017 bp序列片段,发现42个多态位点,28个单倍型。平均单倍型多样性(Hd)和核苷酸多样性(Pi)分别为0.967和0.006,呈现出高单倍型多样性低核苷酸多样性的特点。合浦和钦州群体间遗传分化指数Fst值为-0.029,表明广西的2个群体间没有遗传分化。虎门群体与合浦和钦州群体间的Fst值分别为0.201和0.218,出现中度遗传分化,推测琼州海峡可能阻碍了广东与广西群体间的遗传交流。邻接树上出现2个无明显地理聚群的较弱谱系分支,表明正处于谱系拣选状态。AMOVA分析表明,居氏银鱼群体内遗传差异(86.54%)大于群体间(13.46%)遗传差异,遗传变异主要集中在群体内部。虎门群体中性检测的Tajima’sD为显著负值(-1.847,P=0.018),不对称分布分析呈单峰模式,表明可能在晚更新世(3.2～8.0万年前)经历过种群的快速扩张。建议广东群体和广西群体各作为一个管理保护单位分别加以保护。     

水稻线粒体基因组水平上的蛋白质编码基因克隆方法研究

为探索适用于水稻线粒体基因的克隆方法,以水稻线粒体基因ccmB、nad9为例,分别选用3种不同的方法进行克隆。在对水稻线粒体基因组蛋白质编码基因进行比对分析的基础上,探讨了各种克隆方法的优劣及适用范围。结果表明:常规方法适用于Ⅰ类水稻线粒体基因的克隆,RT-PCR法适用于Ⅱ类水稻线粒体基因的克隆,简易方法只适用于Ⅲ类水稻线粒体基因的克隆。     

Mitochondrial genetic diversity and population structuring of UK bottlenose dolphins (Tursiops truncatus): is the NE Scotland population demographically and geographically isolated?

Concern has been expressed over the status of the bottlenose dolphin population that uses the Moray Firth and adjacent waters in NE Scotland. Consequently, part of this population's range has been proposed as a Special Area of Conservation. Efforts to manage and monitor the status of this population require information on the level of genetic diversity within the population and its genetic relatedness to neighbouring populations to appropriately designate units for management and monitoring. Here we examine mitochondrial genetic diversity within the NE Scotland population, and compare this to other regions around the UK and Ireland. Sequence analysis of 549bp of the mitochondrial DNA control region identified eight unique haplotypes in a sample of 29 individuals. Analysis of molecular variance suggests that the Moray Firth population is genetically more closely related to Welsh animals than to its nearest neighbour population in west Scotland. Furthermore, measures of within-population genetic diversity were markedly lower in the Moray Firth than any other sampled region. The low levels of mtDNA genetic variability observed and its apparent geographic isolation provide further support for the precautionary approach currently being applied to the management of this population, despite the lack of direct evidence of harm.