西藏牦牛微卫星DNA的遗传多样性

为了解西藏牦牛品种或类群的遗传多样性和亲缘关系,文章选用8对微卫星标记引物,利用PCR和复合电泳银染技术,通过计算基因频率(P)、有效等位基因数(Ne)、群体杂合度(He)、多态信息含量(PIC)和遗传距离(D),对西藏11个牦牛类群共480个个体进行了遗传多样性和系统进化分析。结果表明:(1)8个微卫星标记在西藏牦牛类群中均表现出多态性,且均属高度多态位点,遗传多样性丰富;(2)8个微卫星标记的平均多态信息含量在西藏牦牛类群中均高于0.5,其中HEL13最高为0.8496,TGLA57最低为0.7349;在11个牦牛类群中,桑日牦牛的平均多态信息含量最高(0.7949),该群体内部存在较多的遗传变异;丁青牦牛最低(0.7505),则群体相对较纯;(3)在11个牦牛类群中,其杂合度大小分别为:桑日(0.8193)>江达(0.8190)>桑桑(0.8157)>巴青(0.8150)>康布(0.8123)>嘉黎(0.8087)>工布江达(0.8054)>斯布(0.8041)>类乌齐(0.8033)>帕里(0.8031)>丁青(0.7831),西藏东部牦牛的遗传多样性较西部的遗传多样性大,预示西藏东部可能是牦牛的发源地之一;(4)根据遗传距离,用UPGMA法构建聚类关系,表明西藏11个牦牛类群可以分为三大类,即嘉黎牦牛、帕里牦牛、桑桑牦牛、巴青牦牛、类乌齐牦牛、康布牦牛聚为一类,斯布牦牛、工布江达牦牛、桑日额牛、江达牦牛聚为一类,丁青牦牛单独成为一类。综上所述,西藏牦牛的遗传多样性较丰富,所选微卫星标记可用于西藏牦牛遗传多样性的评估。     

西藏牦牛SRAP遗传多样性及分类进化研究

用4对SRAP分子标记引物对西藏11个牦牛类群和四川麦洼牦牛的DNA进行扩增,研究其遗传多样性和分类关系。结果表明,在335头牦牛中,共得到29个基因位点,其中有19个多态位点,多态率占65.52%。12个牦牛群体间的Nei’s遗传多样性和Shannon多样性指数分别为0.048 2和0.073 4,遗传相似系数在0.781 1-0.989 1。巴青牦牛和康布牦牛的遗传多样性指数较其他类群高,分别为0.095 5和0.090 0;桑日牦牛类群的遗传多样性指数最低,仅为0.008 5。这些结果表明,12个牦牛类群的SRAP遗传多样性较低。根据Nei’s遗传距离,利用UPGMAM构建聚类关系图结果显示,嘉黎牦牛、帕里牦牛、类乌齐牦牛、桑桑牦牛、康布牦牛、巴青牦牛、丁青牦牛、斯布牦牛和麦洼牦牛聚为一大类,然后依次才与桑日牦牛、工布江达牦牛和江达牦牛相聚在一起,显示在SRAP分子遗传标记所反映的牦牛基因组的遗传结构中,江达牦牛、工布江达牦牛和桑日牦牛与其他牦牛群体间的亲缘关系较远,牦牛的这种亲缘关系与其地理分布也不一致,说明这12个牦牛的起源、演化关系较复杂,有待于进一步研究分析。     

西藏牦牛mtDNA D-loop区的遗传多样性及其遗传分化

通过测定和分析西藏11个牦牛类群114个个体的mtDNA D-loop区全序列,对西藏牦牛的遗传多样性、类群间的亲缘关系及其遗传分化进行了研究。结果表明:①西藏牦牛mtDNA D-loop区全序列长度为890—896 bp,4种核苷酸T、C、A、G的平均比例分别为28.5%、25.3%、32.4%、13.8%,西藏牦牛mtDNA D-loop区富含碱基A+T,表现出一定的碱基偏好性。②共检测到130个变异位点,占分析总位点数的14.33%;其中单一多态位点85个,占多态位点总数的65.38%,简约信息位点45个,占多态位点总数的34.62%。序列变异中碱基缺失、插入和碱基替换等均有,其中碱基替换变异类型中转换114次,颠换12次,在转换变异类型中以A/G、T/C为主,占95.61%,在颠换变异类型中以A/T为主,占75%。③在114个个体中鉴定出90种单倍型,单倍型多样性为0.981±0.008,核苷酸多样性为0.01056±0.00701,均说明西藏牦牛具有丰富的单倍型类型。④90种单倍型分为2个聚类簇(Ⅰ、Ⅱ),聚类簇Ⅰ包含80种单倍型,占全部单倍型的88.89%,涵盖本研究中所有的西藏牦牛类群;聚类簇Ⅱ中有10种单倍型,占单倍型总数的11.11%,涉及的类群有工布江达、帕里、丁青、巴青、江达、类乌齐、桑桑、桑日、斯布,说明西藏牦牛可能有2个母系起源。⑤西藏牦牛类群间核苷酸分歧度(Dxy)在0.503%—1.416%之间,聚类分析和AMOVA分析显示西藏牦牛可分为两大类,康布牦牛、嘉黎牦牛为一类,其余的牦牛类群为另一类。     

青海高原牦牛mtDNA Cytb基因和D-loop区遗传多样性及系统进化分析

为探究青海高原牦牛的遗传多样性和起源进化关系,本研究通过测定和分析青海高原牦牛155个个体细胞色素b基因(Cytb)和D-loop区全序列,分析多态性及构建系统进化树.结果表明:青海高原牦牛Cytb基因全序列长度为1 140 bp,个体间序列长度无差异,4种核苷酸T、A、G、C的含量分别为26.26％、31.73％、1...     

中国牦牛线粒体DNA多态性及遗传分化

用２０种限制性内切酶分析了我国５个牦牛群体９０个个体的限制性片段长度多态性,其中ＡｖａＩ,ＡｖａＩＩ、ＢｇｌＩＩ、ＥｃｏＲＩ．ＨｉｎｄＩＩＩ、ＨｐａＩ６个酶切类型具有多态性,共发现５种ｍｔＤＮＡ单倍型,每种单倍型中检出５０－５５个位点,并利用双酶切制定出其物理图谱。我国牦牛群体ｍｔＤＮＡ多样度ＨＴ为０．１０６５,群体内的平均一致性概率为０．８９６６,表明我国牦牛群体ｍｔＤＮＡ多态性较贫乏,群体间的平均净遗传距离Ｐｅｔ为０．０００２０１,群体基因分化系数Ｇｓｔ为０．０２９１,我国牦牛群体ｍｔＤＮＡ变异只有２．９１％来自群体间的差异,群体间的分化程度较低。并根据报道,比较了牦牛和其他家养牛种的ｍｔＤＮＡ遗传分化,估计出牦牛和普通牛、瘤牛的分化时间大约分别在１．１－２．２百万年和１．０１－１．０２百万年之间。     

家牦牛线粒体DNA(mtDNA)遗传多样性及其分类

通过分析包括我国10个家牦牛品种(类群)在内共296个样本的mtDNA控制(D-loop)区部分序列的遗传变异,对我国家牦牛的遗传多样性、遗传分化、聚类关系和分类进行了研究.所测序列经比对后,共检测到61个变异位点,定义了77种单倍型.分析显示青海环湖牦牛的单倍型多样性最高,达0.9848±0.0403,而巴州牦牛单倍型多样性最低,为0.8000±0.0825;核苷酸多样性方面,斯布牦牛存在最为丰富的核苷酸序列变异,核苷酸多样性值为0.022582±0.011767,而巴州牦牛仅为0.006856±0.002476,表明我国家牦牛品种(类群)遗传多样性水平存在较大差异.总体上,我国家牦牛单倍型多样性、核苷酸多样性分别为0.9251±0.0095和0.015265±0.007757,呈现出丰富的遗传多样性.聚类分析显示我国家牦牛存在两个聚类簇--斯布牦牛独立为一类;其余9个品种(类群)聚为一类,表明家牦牛品种(类群)间遗传距离与地理分布无明显相关.分子变异分析(AMOVA)显示九龙、嘉黎、斯布牦牛构成的组与其余7个家牦牛品种(类群)构成的组之间存在极显著的遗传分化(?CT=0.05285,P<0.01),且其品种间/组内遗传分化不显著(?SC=0.00648,P>0.05),支持依据遗传分化程度将我国家牦牛划分为两大类型.AMOVA支持的分组在品种(类群)组成上与蔡立的研究结果相符,首次为我国家牦牛划分为横断高山型和青藏高原型两种类型提供了源自分子遗传学的证据.     

中国狼不同地理种群遗传多样性及系统进化分析

为了解中国狼不同地理种群遗传多样性及系统发育情况,从中国境内狼的主要分布区青海、新疆、内蒙古和吉林4个地区采集样品,用分子生物学技术手段成功地获得44个个体线粒体DNA控制区第一高变区(HVRⅠ)序列和40个线粒体Cyt b部分序列。线粒体控制区HVRⅠ共检测到51个变异位点,位点变异率为8.76%;线粒体Cyt b部分序列发现31个变异位点,位点变异率为5.33%,未见插入及缺失现象,变异类型全部为碱基置换。共定义了16个线粒体HVRⅠ单倍型,其中吉林与内蒙种群存在共享单倍型,估计这两地间种群亲缘关系较近。4个地理种群中新疆种群拥有较高的遗传多样性(0.94)。中国狼种群总体平均核苷酸多态性为2.27%,与世界其他国家地区相比,中国狼种群拥有相对较高的遗传多样性。通过线粒体HVRⅠ单倍型构建的系统进化树可以看出,中国狼在进化上分为2大支,其中位于青藏高原的青海种群独立为一支,推测其可能长期作为独立种群进化。基于青海种群与新疆,内蒙种群的线粒体Cyt b遗传距离,推测中国狼2个世系可能在更新世冰川时期青藏高原受地质作用急速隆起后出现分歧,分歧时间大约在1.1 MY前。     

鱼类线粒体DNA的遗传与进化

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基于线粒体DNA的中国亚洲象种群遗传多样性及种群遗传结构

亚洲象是我国国家一级保护动物.本文利用非损伤性取样法,以亚洲象粪便中脱落的肠道上皮细胞为DNA来源,选用线粒体DNA作为分子标记,对分布于我国境内的亚洲象种群的遗传结构和种群遗传多样性进行研究.本研究得到mtDNA序列片段长度为556 bp,经对178个个体进行扩增结果分析,共得到24个单倍型.在5个地理种群中,除南滚河种群外,其他4个种群中的114个个体共享同一单倍型,南滚河种群与其他种群间未观察到共享单倍型.系统发生分析,观察到中国境内现有亚洲象种群在进化上分为两大分支,α和β.其中分支α中包含除南滚河种群外的4个地理种群,分支β仅含有南滚河种群,表明南滚河种群与其他4个地理种群间存在明显分化.遗传多样性分析结果表明,中国境内的亚洲象种群的遗传多样性水平较低,分析原因认为是栖息地破碎化阻断了种群间有效的基因交流.     

松江鲈线粒体DNA控制区结构和遗传多样性分析

为探讨松江鲈(Trachidermus fasciatus Heckel)线粒体控制区特征及其群体遗传结构, 研究测定分析了中国和日本沿海共8个群体的线粒体控制区序列, 分析了其结构特征, 识别出终止序列区(ETAS)、中央保守区(CD)和保守序列区(CSB)的特征序列。遗传多样性分析结果显示: 69个松江鲈个体共检测到47个单倍型, 呈现出核苷酸多样性(0.0079)较低和单倍型多样性(0.978)较高的特点。单倍型邻接关系树和单倍型网络关系图均显示松江鲈分为中国和日本两大世系。遗传分化系数(Fst)和分子方差分析(AMOVA)结果表明, 松江鲈中国群体和日本群体之间存在的遗传差异较显著, 中国沿海各群体之间亦存在着一定程度的遗传差异, 该分化主要由历史环境变动、当代环境因素和自身生态习性等原因造成。     

藏羚羊mtDNA D-Loop区遗传多样性研究

该研究采用非损伤性DNA基因分型技术,对可可西里地区10个藏羚羊（Pantholops hodgsonii）个体的mtDNA非编码区部分片段（444~446bp）进行了序列分析,结果显示A、T%含量（61.8%）明显高于G、C%含量（38.2%）,共发现10种单倍型,包括48个多态位点,其中转换位点44个、颠换位点1个、插入位点1个、缺失位点2个。单倍型间平均遗传距离为0.031,单倍型多态性（h）为1.000,核苷酸多态性（π）为2.96%。说明藏羚羊线粒体控制区存在着丰富变异,最后从藏羚羊的生态习性及地理分布两方面对这一结果进行了分析探讨。      

黄山短尾猴mtDNA控制区序列变异及种群的遗传多样性

短尾猴属灵长目(Primates)猴科(Cercopithecidae)猕猴属(Macaca),是我国特有的国家二级保护动物。为了更有效地保护其野生种群,本文研究了黄山短尾猴种群内的遗传多样性,并对黄山短尾猴与四川短尾猴种群间的遗传差异进行了分析。共测定了黄山短尾猴7个群体中的30个样本的mtDNA控制区5′端493bp的序列,只发现了7个变异位点,定义了3种单倍型,单倍型序列之间缺乏变异,种群中的核苷酸多样性很低(0.006);3种单倍型相应地将黄山种群分为了3个亚群,不同亚群之间呈现出一定的片断化分布,从分子水平上初步揭示了短尾猴黄山种群的遗传多样性。与四川短尾猴的相应序列比较,黄山短尾猴控制区序列存在很大差异,共有59个变异位点,而且存在大片段的碱基插入/缺失,有78%的遗传变异发生在两个种群之间,两个种群间的核苷酸歧异度已达8.21%。进一步分析表明,黄山短尾猴与四川短尾猴之间存在着极显著的遗传分化(FST=0.399,P<0.001),基于最大似然法和邻接法构建的系统发生树均将两者聚为不同的类群,支持将它们归入各自的管理单元。     

陕西省林麝mtDNA D-loop区序列结构和种群遗传多样性

林麝(Moschus berezovskii)曾广泛分布于中国,由于盗猎和栖息地缩小,秦岭地区野生种群数量迅速下降,圈养繁殖种群已成立了几十年,但大多数圈养种群的遗传背景不清,种群规模增长非常缓慢。为了给这一物种的保护和管理提供有用的信息,调查了陕西省林麝1个圈养种群3个野生种群线粒体DNA(mt DNA)D-Loop 632 bp片段的遗传多样性和种群结构。在69个个体中其碱基组成为A+T的平均含量63.2%高于G+C含量36.8%,共检测到变异位点171个(约占总位点数的27.05%)。核苷酸多样性(Pi)为0.04424,平均核苷酸差异数(K)为19.908。69个个体分属32个单倍型,单倍型间的平均遗传距离(P)为0.070。32个单倍型构建的NJ系统树聚为3个分支,4个林麝群体中的单倍型是随机分布的。4个群体的平均遗传距离为0.043(标准误SE为0.005),凤县养殖场群体与留坝和陇县群体的亲缘关系较远。单倍型间的平均遗传距离为0.043,可见其遗传分化尚未达到种群分化的水平。结果表明,陕西省林麝群体mt DNA D-loop区序列存在着较丰富的变异和遗传多样性,凤县野生群体和凤县养殖场群体的核苷酸多样性和单倍型多样较高,养殖场种群没有出现近亲繁殖及遗传多样性下降的情况。凤县野生群体和凤县养殖场群体两者遗传分化较小,存在着较高的基因流水平。     

Genetic diversity of Asian water buffalo (Bubalus bubalis): mitochondrial DNA D-loop and cytochrome b sequence variation

Swamp and river buffalo mitochondrial DNA (mtDNA) was sequenced for 303 bp of the cytochrome b gene for 54 animals from 14 populations, and for 158 bp of the D-loop region for 80 animals from 11 populations. Only one cytochrome b haplotype was found in river buffalo. Of the four haplotypes identified in swamp buffalo, one found in all populations is apparently ancestral both to the other swamp haplotypes and to the river haplotype. The phylogenetic relationships among the 33 D-loop haplotypes, with a cluster of 11 found in swamp buffalo only, also support the evolution of domesticated swamp and river buffalo from an ancestral swamp-like animal, most likely represented today by the wild Asian buffalo ( Bubalus arnee ). The time of divergence of the swamp and river types, estimated from the D-loop data, is 28 000 to 87 000 years ago. We hypothesise that the species originated in mainland south-east Asia, and that it spread north to China and west to the Indian subcontinent, where the rive type evolved and was domesticated. Following domestication in China, the domesticated swamp buffalo spread through two separate routes, through Taiwan and the Philippines to the eastern islands of Borneo and Sulawesi, and south through mainland southeast Asia and then to the western islands of Indonesia.     

A survey of equid mitochondrial DNA: Implications for the evolution, genetic diversity and conservation of Equus

The evolution, taxonomy and conservation of the genus Equuswere investigated by examining the mitochondrial DNA sequences of thecontrol region and 12S rRNA gene. The phylogenetic analysis of thesesequences provides further evidence that the deepest node in thephylogeny of the extant species is a divergence between twolineages; one leading to the ancestor of modern horses (E.ferus, domestic and przewalskii) and the other to thezebra and ass ancestor, with the later speciation events of the zebrasand asses occurring either as one or more rapid radiations, or withextensive secondary contact after speciation. Examination of the geneticdiversity within species suggested that two of the E. hemionussubspecies (E. h. onager and E. h. kulan) onlyrecently diverged, and perhaps, are insufficiently different to beclassified as separate subspecies. The genetic divergence betweendomestic and wild forms of E. ferus (horse) and E.africanus (African ass) was no greater than expected within anequid species. In E. burchelli (plains zebra) there was anindication of mtDNA divergence between populations increasing withdistance. The implications of these results for equid conservation arediscussed and recommendations are made for conservation action.     

Genetic diversity of golden takin (Budorcas taxicolor bedfordi) population from Qinling Mountains in China revealed by sequence analysis of mitochondrial DNA control region

The golden takin is an endangered species, listed as a First Grade Protected animal and found only in the Qinling Mountains in China. A great deal of research on the golden takin's living habitat, population size, and home range has been conducted. Here, we employed sequence analysis of the mitochondrial DNA control region to study the genetic diversity of the golden takin from three separate nature reserve parks in the Qinling Mountains. We also compared the results of our study with previously published data on the genetic diversity of mixed takin species located in the Qinling Mountains and the Minshan area. Based on 62 sampled golden takin individuals, we found an overall mean genetic haplotype diversity of 0.687. There is no significant geographic genetic diversity across different golden takin populations within the Qinling Mountains. However, we did show significant diversity between golden takin from the Qinling Mountains and from Minshan. These original data provide a foundation for the genetic diversity of golden takin, and will yield comprehensive information for better supporting the management in the national reserve parks.     

Genetic diversity of Cheju horses (Equus caballus) determined by using mitochondrial DNA D-loop polymorphism

We used sequence polymorphism of the mitochondrial DNA D-loop (968 bp excluding the tandem repeat region) to determine genetic diversity of horses inhabiting Cheju (a southern island of Korea). Seventeen haplotypes with frequencies from 1.5 to 21.5% were found among 65 Cheju horse samples. Genetic diversity (h) of the 17 haplotypes was calculated to be 0.91, indicating that the extant Cheju horse population consists of diverse genetic groups in their maternal lineage. Phylogenetic analysis showed that 17 types of Cheju (D-loop sequences determined), 5 Mongolian, 6 Arabian, 3 Belgian, 2 Tsushima, 2 Yunnan, 1 Przewalskii, and 3 Thoroughbred horses (published sequences for the latter seven breeds) showed that Cheju horses were distributed into many different clusters in the tree. Four Mongolian horses clustered with separate Cheju horse groups, showing that some Cheju horses are clearly of Mongolian origin. The analysis of partial sequences (284 bp) of the D-loop of 109 horses showed that Thoroughbred, Mongolian, Lipizzan, and Arabian breeds are as diverse as Cheju horses. Our data together with others' suggest that most horse breeds tested with reasonably sufficient numbers of samples are diverse in their maternal lineages and also are not uniquely different from each other.