江西井冈山地区灰胸竹鸡的遗传多样性研究

灰胸竹鸡Bambusicola thoracica是我国特有鸟类.本文采用聚合链式反应和直接测序的方法测定井冈山地区灰胸竹鸡3个种群线粒体DNA(mtDNA)控制区1142 bp的序列,分析其序列变异和种群遗传多样性.30个样本共发现16个变异位点和10种单倍型,其中hapl广泛分布,占所分析样本的23.33%,是其祖先单倍型.3个种群的平均单倍型多样性和核苷酸多样性分别为0.815和0.00243.青原区种群与其它两个种群遗传分化显著,基因交流受限制.受隔离影响,青原区种群遗传多样性最低.在系统发生树上,10种单倍型形成两支,井冈山种群和永新县种群聚在一起,与其地理位置相一致.     

笼养灰胸竹鸡的繁殖行为

于1999年3－7月对笼养条件下灰胸竹鸡的繁殖行为进行了观察。结果表明,笼养灰胸竹鸡仍保留求偶,交配和产卵等野外繁殖行为,但营巢,邻域,孵卵和育雏行为基本消失,求偶和交配于3出现,5月达到高峰,8月以后繁殖行为基本消失,本文还分析了笼养灰胸竹鸡繁殖期的觅食行为。     

棕胸竹鸡觅食行为的观察

对笼养条件下棕胸竹鸡（Bambusicola fytchii fytchii）每日的觅食节律的时间、频次、求偶取食行为和社群等级之间的关系进行了观察。结果表明：影响棕胸竹鸡觅食行为的主要因素是一天中它在地面上活动、静栖、游走及饮水等项行为所占时间的长短。影响求偶取食行为的主要因素是它在地面上活动的总时间和理羽、攻击及其它的求偶活动所占的时间多少。社群等级对棕胸竹鸡的觅食行为有一定的影响,但不甚显著。     

灰胸竹鸡血清某些生化参数的测定

运用自动生化分析仪测定了21只野生成年灰胸竹鸡的血液生化参数,结果表明:雌性在总蛋白、白蛋白和球蛋白水平,以及谷丙转氨酶活性均高于雄性(P>0.05),雌性白蛋白/球蛋白却较雄性低;同样,雌性个体的总胆红素、总胆固醇和甘油三酯的含量分别较雄性高8.33%、23.08%和15.38%(P>0.05).提示雌性个体的代谢较雄性个体要强,可为深入探讨竹鸡的机体代谢规律提供资料.     

灰胸竹鸡的生物学特性及经济价值

本文从形态特征、生活习性、繁殖和血液生理生化特点等方面介绍了灰胸竹鸡生物学特性和经济价值,对灰胸竹鸡的人工驯养与繁殖,以及保护性开发具有重要意义。     

笼养灰胸竹鸡的活动时间分配

采用直接观察法对灰胸竹鸡在笼养条件下的活动时间分配及行为特点进行研究,结果表明笼养条件下灰胸竹鸡的主要行为有走动、站立、取食、静卧4种,一天中有两个活动高峰,雄鸡的活动强于雌鸡;白天休息时间占40%以上,采食集中在上午和傍晚进行;站立、取食、静卧发生的频次在雌雄之间无显著差异（P〉0．05）,而走动的频次雄鸡极显著的高于雌鸡（P〈0．01）,各行为每频次在持续时间上差异不显著（P〉0．05）。     

棕背(鼠平)和红背(鼠平)种间区分的分子方法

棕背鼠平(Myodes rufocanus)和红背鼠平(M.rutilus)的分布有重叠区且外形相似,在特定情况下存在种间区分困难,给两种鼠的数量调查带来不便和误判.本研究通过mtDNA控制区构建系统树、mtDNA控制区电泳和RAPD 3种分子生物学方法有效地对棕背(鼠平)和红背(鼠平)已知的8个样本和16个待定样本进行了准确鉴定.其中,mtDNA控制区电泳进行种问区分的方法具有简便、准确而又快捷的优点.     

人癌细胞线粒体DNA控制区序列特征分析

为了探讨癌细胞mtDNA控制区序列的变化特征, 采用PCR产物限制性片段长度多态性(PCR-RFLP)分析与直接测序相结合的方法,对比分析6株人癌细胞系、 6例癌患者及4例健康成人白细胞mtDNA控制区序列.发现第16519位T→C、16 534位A→G、46位T→G和49位A→C突变, 在癌细胞系和癌患者白细胞mtDNA中分别占50%(3/6)和33.3%(2/6), 健康成人白细胞mtDNA中未见此类型突变;第16 278位C→T突变,在癌细胞系mtDNA中占50%(3/6),显著高于正常人群mtDNA中此位点的多态性变异.表明癌细胞和癌患者白细胞mtDNA重链复制起点及其相邻D环区的特征性突变可能与细胞癌变/或癌的易感性有关.     

基于线粒体DNA控制区的斑翅草螽不同地理种群遗传分化研究

采用PCR扩增结合DNA克隆测序技术,分析了斑翅草螽Conocephalus maculates 9个地理种群mtDNA控制区序列的变异及遗传多样性。切除侧翼RNA基因序列后,最终获得的斑翅草螽mtDNA控制区比对后全长为676 bp,平均碱基组成T(37.8%),C(11.7%),A(41.3%)和G(9.1%)。共检测到98个可变位点,占总位点数的14.5%,其中,9处碱基插入/缺失,74处转换(40个T/C,34个A/G),50处颠换(18个A/T,11个T/G,15个A/C,6个C/G)。共定义46个单倍型,其中,4个为种群间共享单倍型(H02、H05、H08和H10),其余42个为各种群独有单倍型,包括6个种群内共享单倍型(H09、H11、H15、H18、H26和H38)。单倍型总数占实验个体总数的69.7%,除四川峨眉山外,其余种群单倍型百分比均﹥50%。通过两两地理种群间的FST值差异显著性检验,将这些群体分为4组,分别为SC+CQ,GX+FLB+HN+YN,XZ和HB。以长瓣草螽C.gladiatus、峨眉草螽C.emeiensis、悦鸣草螽C.melaenus、竹草螽C.bambusanus为外群,构建的斑翅草螽mtDNA控制区单倍型NJ法系统树形成3个自举支持度较高的分支,其中,分支A由28种单倍体组成,包括本研究中除四川峨眉山(SC)和重庆万州(CQ)以外的7个种群;分支B由12种单倍体组成,包含除菲律宾拉乌尼翁(FLB)和江西南昌(JX)以外的7个种群;分支C由6种单倍型组成,全部来自西藏林芝(XZ)的单倍型。聚类结果表明,斑翅草螽不同地理种群间的遗传分化并不明显,即使是两两群体间FST值差异显著的群体,也未能形成完全独立的分支。     

都柳江鲤、鲫和草鱼种群mtDNA控制区及遗传多样性分析

采用PCR和DNA测序技术对贵州都柳江鲤(Cyprinus carpio)、鲫(Carassius auratus)和草鱼(Ctenopharyngodon idellus)种群的mtDNA控制区序列及遗传多样性进行了研究。获得了都柳江鲤、鲫和草鱼mtDNA控制区长度分别为899~901 bp、787 bp和901~905 bp的序列。该3种鱼类控制区碱基A、T含量较高,G含量最低。识别了该3种鱼类mtDNA控制区终止序列区、中央保守区和保守序列区等保守序列。其中,除CSB-2和CSB-3碱基组成相同外,其余核心序列碱基组成存在着差异。都柳江鲤、鲫和草鱼种群mtDNA控制区分别有24、24和11个多态位点,分属12、17和8个单倍型。都柳江鲤、鲫种群遗传多样性较高,草鱼种群遗传多样性较低。因此,有必要开展都柳江草鱼种群遗传多样性的保护。     

基于线粒体COⅠ和16S rRNA基因序列比较分析东海带鱼群体遗传多样性

测定了东海带鱼(Trichiurus lepturus Linnaeus)三个群体(命名为A: 122°32′E 29°55′N、B: 123°30′E 26°75N; C: 124°24′E 27°26′N)72个个体的线粒体DNA16S rRNA和COⅠ基因序列,通过单基因序列和联合序列分析, 研究了东海带鱼群体的遗传变异情况。分别得到1130 bp的COⅠ基因序列片段和554 bp的16S rRNA序列片段, 其中COⅠ基因片段的T、C、A、G含量分别为29.0%、28.9%、24.4%和17.7%; 16S rRNA基因片段的T、C、A、G含量分别为22.7%、27.6%、28.0%和21.7%。基于线粒体16S rRNA、COⅠ和16S+COⅠ基因序列分析, 72个个体中分别确定43个, 8个和49个单倍型, 存在单倍型共享现象。群体的单倍型多样性指数为0.9766—0.9992, 显示了群体内的单倍型较为丰富。3个群体间各序列平均核苷酸差异数(K)在5.111—9.024和0.0045—0.0076, 核苷酸多样性指数(π)为0.0048—0.0084, 显示不同带鱼群体遗传多态性丰富。使用邻接法构建的分子进化树揭示同一群体内大部分个体聚在一起。分析结果表明, 群体A遗传背景比群体B、群体C较为丰富, 群体内部个体差异大于群体间差异, 群体间基因交流频率较高, 遗传分化不明显, 初步判定东海带鱼3个群体的遗传多样性偏低。     

野桑蚕性信息素结合蛋白基因pbp1、气味受体基因or1和or3的克隆及其与家蚕同源基因的进化分析

昆虫能够特异性识别同类异性。雄蚕蛾对雌蚕蛾感知定位过程中, 性信息素结合蛋白PBP1、气味受体OR1和OR3起重要作用。为研究家蚕Bombyx mori和野桑蚕Bombyx mandarina杂交困难的分子机制, 了解性识别相关基因的进化, 本研究克隆得到了野桑蚕的性信息素结合蛋白基因pbp1（GenBank注册号：GQ246497）和气味受体基因or1（Genank注册号：GQ246496）和or3（GenBank注册号：GQ246498）。序列分析发现, 家蚕与野桑蚕相比, pbp1基因存在4个SNP位点, 分别为C10A, A40T, T270C和A333G, 其中2个SNP位点引起氨基酸的改变, 分别为Q→K和N→Y; or1基因存在5个SNP位点, 分别为T910C, A1147C, A1192T, T1276C和G1282A, 其中1个SNP位点引起氨基酸F→L的改变; or3基因存在4个SNP位点, 分别为A507G, A513G, T605C和G672A, 其中1个SNP位点引起氨基酸I→T的改变。3个基因的遗传距离很近, 进化速率也很慢。氨基酸的分子量和等电点有细微差异或无差异。PHD预测的二级结构表明, 变异位点对附近区域的结构没有任何影响, 功能位点也没有变化。推测家蚕与野桑蚕之间, 这些基因功能可能没有差异, 即二者的雌雄性个体间可以相互感知、识别, 这与实验观察结果一致。     

岩原鲤遗传多样性和种群历史动态研究

研究基于线粒体DNA细胞色素b (mtDNA Cyt b)基因序列, 对2013—2017年间采自我国长江上游贵州省赤水市和重庆市万州区共161尾岩原鲤(Procypris rabaudi)个体进行了遗传多样性分析。结果表明, 在所有个体序列中, A、T、C、G碱基的平均含量分别为30.2%、27.9%、28.2%和13.7%, (A+T)含量(58.1%)明显大于(G+C)含量(41.9%), 表现出较强的反G偏倚性。161条序列检测到18个变异位点, 定义了15种单倍型, 整体单倍型多样性指数(H_d)、核苷酸多样性指数(P_i)分别为0.590、0.00132; 岩原鲤赤水群体遗传多样性水平低于万州群体; 万州群体的单倍型多样性和核苷酸多样性均呈现逐年降低的趋势, 但是赤水群体的单倍型多样性和核苷酸多样性呈现逐年增加的趋势。基于最大似然法构建的系统发育树和单倍型网络图结果一致, 万州和赤水群体并未形成明显的地理分布格局。Mega 6.0软件计算2个群体之间的遗传距离为0.001。F_st值统计表明, 2个地理群体间F_st值为0.01749 (P>0.05), 群体间没有出现遗传分化现象。两群体间基因交流频繁, 基因流N_m=24.71。分子方差分析(Analysis of Molecular Variance, AMOVA)显示: 98.25%的遗传变异是由群体内产生的。中性检验结果表明万州岩原鲤群体历史上曾发生过种群扩张事件, 时间约为0.15百万年前。岩原鲤群体整体上遗传多样性偏低, 急需提出合理的管理措施, 以加强长江流域岩原鲤物种的资源保护。     

Variability of milk fat globule membrane protein gene between cattle and riverine buffalo.

A study on butyrophilin (BTN) gene was conducted to detect variability at nucleotide level between cattle and buffalo. Hae III PCR-RFLP was carried out in crossbred cattle and it revealed polymorphism at this locus. Three genotypes namely, AA, BB and AB and two alleles were observed with frequencies 0.78, 0.17, 0.04 and 0.87, 0.13, respectively. The sequences of different cattle, buffalo and sheep breeds have been reported in the EMBL gene bank with accession numbers: AY491468 to AY491475. The nucleotides, which have been substituted from allele A to B, were found to be C to G (71st nucleotide), C to T (86th nucleotide), A to T (217th nucleotide), G to A (258th nucleotide), A to C (371st nucleotide) and C to T (377th nucleotide). The nucleotide substitution at 71st, 86th and 377th position of the fragment were expected to be a silent mutation where as nucleotide changes at 217th, 258th and 371st positions were expected to be substituted by lysine with arginine, valine with isoleucine and leucine with proline in allele B. The differences of nucleotides and amino acids between cattle, buffalo and sheep breeds have been revealed and on the basis of nucleotide as well as protein variability the phylogenetic diagram have been developed indicating closeness between cattle and buffalo.     

Environmental Shaping of Ribosomal RNA Nucleotide Composition

Ribosomal RNA (rRNA) is one of the most important macromolecules in the cell. It is well established that high-temperature environmental conditions destabilize rRNA, leading to a selection for G+C-rich stabilizing structures. Our knowledge about the nucleotide composition effect of other environmental conditions, however, is limited. In the present work, I addressed this by correlating the rRNA nucleotide composition to known environmental habitats for bacteria. The bacterial phyla Firmicutes, Actinobacteria, and Proteobacteria were chosen for in-depth analyses due to the abundance of information available in the databases. Major differences in nucleotide composition were identified between these phyla. In addition to the G+C-->A+T gradients, a main gradient of G+A-->C+T was identified for Firmicutes, while a G+T-->A+C gradient was identified for Actinobacteria. With respect to correlation to environmental conditions, the Firmicutes showed a main structure of high G+C being correlated to thermophilic conditions, high A+T to anaerobic conditions, and high C+T to halophilic conditions. The main patterns detected for Firmicutes can be explained by structural stability for high G+C, chemical instability of G under aerobic conditions, and structural stability by purine/pyrimidine skew for halophilic conditions. On the contrary, the correlations for Actinobacteria cannot easily be explained by chemical and/or structural stability. This may indicate interference with factors not included in my work. Finally, I found a main correlation between high A+T and endosymbiosis for Proteobacteria. High A+T probably reflects adaptation to cell internal growth. Further support for environmentally driven nucleotide composition shaping was found and that polyphyletic bacteria were associated with the same environment/nucleotide correlations. My conclusion is that environmental conditions and habitats have a major effect on rRNA nucleotide composition but that the effects may differ between the bacterial phyla.     

The rate and pattern of nucleotide substitution in Drosophila mitochondrial DNA.

The nucleotide sequences of a segment of mitochondrial DNA (mtDNA) have been determined for nine species or subspecies of the subgenus Drosophila of the genus Drosophila. This segment contains two complete protein-coding genes (i.e., NADH dehydrogenase subunit 1 and cytochrome b) and a transfer RNA gene (tRNA(ser)). The G+C content at third-codon positions for the two protein-coding genes was 1.5 times higher than that in the D. melanogaster species group, which belongs to the subgenus Sophophora. However, there was a substantial difference between the nucleotide frequencies of G and C. The number of nucleotide substitutions per silent site was more than three times higher than that for nuclear DNA, although it was only 60% of that for mammalian mtDNA. Both parametric and nonparametric analyses revealed a strong transition-transversion bias in nucleotide substitution, as was observed in mammalian mtDNA. Moreover, the rate of substitution of A and T for G and C is higher than that for the opposite direction. This bias seems to be responsible for the extremely A+T-rich base composition of Drosophila mtDNA. It is also noted that the rate of transitional change between A and G is higher than that between T and C.     

茄科植物叶绿体基因组插入、缺失和核苷酸替代的发生方式及影响

摘要: 核苷酸替代和indels(插入、缺失统称)发生是进化的重要动力。以茄科植物为研究对象, 探讨茄属中番茄和马铃薯、烟草属中绒毛状烟草和普通烟草分化时叶绿体基因组indels和核苷酸替代的发生方式, 以及这两种突变对基因组造成的影响。结果显示: indels和核苷酸替代的发生都不是随意的。indels发生在A+T丰富的区域, 1 bp indels占据总数的30%以上, 大部分indels都为低于10 bp的较短片段。核苷酸替代表现出Ts(转换)/Tv(颠换)偏差, 但T→G, A→C颠换频率却明显增加。Ts/Tv比值出现种属特异性, 番茄和马铃薯比较时替代的Ts/Tv比值低于绒毛状烟草和普通烟草比较时Ts/Tv比值。不同物种替代的(A+T)/(G+C)比值有一定差异, 从而影响基因组的(G+C)%, 此比值的差异与形成物种的生长习性有一定的关系。     

白纹方蟹线粒体基因组全序列测定及方蟹总科比较分析

为探讨该总科内部亲缘关系及其与线粒体基因排序之间的相关性,研究以方蟹科(Grapsidae)白纹方蟹(Grapsus albolineatus)为代表种,测定其线粒体基因组全序列。其全长为15577 bp,包含13个蛋白编码基因,22个tRNA基因, 2个rRNA基因和1个控制区。基因组碱基组成为33.4%A、12.0%G、20.6%C和34.0%T,具有明显的AT偏向性(67.4%)。除ATP8和ND1以GTG作为起始密码子外,其余蛋白编码基因均以ATN作为起始密码子;除COⅡ和Cyt b以T作为不完全终止密码子外,其余基因均以TAN作为终止密码子。亮氨酸(Leu)和半胱氨酸(Cys)分别是使用频率最高(15.28%)和最低(0.81%)的两种密码子。除tRNA-Ser1缺少DHU臂外,其余tRNA均能形成典型的三叶草结构。基于13个蛋白编码基因的核苷酸序列同时构建了方蟹总科的贝叶斯树(BI)和最大似然树(ML),两种方法构建的系统发育树扑拓结构一致,均显示所有方蟹科(Grapsidae)种类聚在一起,其中白纹方蟹与同属的细纹方蟹(G. tenuicrustatus)的亲缘关系最近;...     

A new restriction endonuclease Eco31I recognizing a non-palindromic sequence

A restriction endonuclease with a novel site-specificity has been isolated from the Escherichia coli strain RFL31. The nucleotide sequences around a single Eco31I cut on pBR322 DNA and two cuts of λ DNA have been compared. A common ^5′GAGACC_3′CTCTGG sequence occurs near each cleavage site. Precise mapping of the cleavages in both DNA strands places the cuts five nucleotides to the left of the upper sequence and one nucleotide to the left of the lower sequence. This enabled us to deduce the following recognition and cleavage specificity of Eco31I: 5 ′ G G T C T C N ↓ 3 ′ C C A G A G N N N N N ↑     

Single nucleotide polymorphisms in the open reading frame of the stearoyl-CoA desaturase gene and resulting genetic variants in Canadian Holstein and Jersey cows.

Stearoyl-CoA desaturase (SCD) catalyzes the synthesis of conjugated linoleic acid (CLA) and mono-unsaturated fatty acids (MUFA) from their saturated counterparts in the mammary gland and adipose tissue of ruminant animals. We hypothesize that single nucleotide polymorphisms (SNPs) in the SCD gene account for some of the differences in SCD activity, and consequently for some of the variations in CLA and MUFA content of milk fat between Holsteins and Jersey cows and within these two breeds. We analyzed the open reading frame of the SCD gene of 44 Holsteins and 48 Jerseys for SNPs by sequencing. Three SNPs: 702A --> G, 762T --> C and 878C --> T were identified in both breeds and a further SNP, 435G --> A, was unique to Holsteins. The SNPs characterized four different genetic variants in Holsteins: A (G(435)A(702)T(762)C(878)), A1 (A(435)A(702)T(762)C(878)), B (G(435)G(702)C(762)T(878)) and B1 (A(435)G(702)C(762)T(878)), with only variants A and B in Jerseys. SNP 878C --> T resulted in a non-synonymous codon change while the rest resulted in synonymous codon changes giving rise to two protein variants, A having alanine and B having valine. Allele A was the most prevalent in the two breeds. These differences may, therefore, contribute to existing variations in CLA and fat content between and within Canadian Holstein and Jersey cows.