Evaluation of genetic architecture and mutation drift equilibrium of Marathwada buffalo population in Central India

In the present study, microsatellite data on 24 loci were generated and utilized to evaluate the genetic architecture and mutation drift equilibrium of Marathwada buffaloes, a Central Indian population maintained under low input system. Sufficient allelic diversity was observed with a total of 109 alleles across different loci. The genetic diversity analysis of Marathwada buffaloes displayed moderate level of within breed variability in terms of mean number of alleles per locus (4.48) and heterozygosity values (Ho = 0.532, He = 0.624). The studied Indian buffalo population showed considerable heterozygote deficiency (F_IS = 0.138) and deviation from HWE at many investigated loci. Three quantitative tests viz. sign test, standardized difference test and Wilcoxon sign rank test and a qualitative test for mode shift distortion of allelic frequencies were employed to evaluate mutation drift equilibrium under three different models of microsatellite evolution. The population was found to deviate significantly under IAM and TPM, while it was reverse under SMM. The qualitative test for mode shift supported the results under SMM indicating the absence of genetic bottleneck in the recent past in Marathwada buffaloes.     

Evaluation of genetic variability and mutation drift equilibrium of Banni buffalo using multi locus microsatellite markers

The present study was conducted to evaluate genetic diversity of Banni buffalo and its relationship/differentiation with Murrah using genotypic data on 24 heterologus bovine specific microsatellite marker loci. A total of 138 alleles were observed with a mean of 5.75 alleles/locus across two populations. The mean observed and expected heterozygosities were found to be 0.441 and 0.572 respectively in Banni buffaloes while it was 0.464 and 0.610 respectively in Murrah buffaloes. The average heterozygosity deficit was significantly positive with substantially higher values observed in Banni (22.3%) and Murrah (24%) buffalo populations. Banni buffalo population, when evaluated for mutation drift equilibrium revealed significant heterozygosity excess under IAM while no such excess was observed under SMM and TPM. The qualitative graphical test revealed a normal L-shaped distribution of allele frequencies indicating the absence of genetic bottleneck in Banni buffaloes. The mean estimates of F-statistics over all the loci were 0.376 for F_IT, 0.187 for F_ST and 0.232 for F_IS respectively. Analysis of molecular variance (AMOVA) revealed 18.95% of the total variation being explained by between breed differences while 14.36% of the variation explained differences between individuals within each breed. Genotype assignment test revealed distinct clustering of Banni and Murrah buffaloes. Genetic distance was estimated using three different methods, the results of which revealed considerable genetic differentiation between these two buffalo populations. The divergence time between Banni and Murrah buffaloes was estimated to be around 7286 years. The results of the present study may be helpful in decision making for conservation programs as Banni buffalo population is on decline.     

中国5个矮马品种的瓶颈效应分析

利用13个微卫星基因座对中国5个矮马品种(德保、贵州、宁强、四川、云南)群体进行了遗传平衡检测。根据微卫星等位基因频率,应用无限等位基因模型(infinite allele model,IAM)、双相突变模型(two-phased model of mutation,TPM)和逐步突变模型(step-wise mutation model,SMM)3种模型,符号和Wilcoxon 符号—秩2种检验方法,对5个矮马群体的突变－漂移平衡进行分析。结果表明,在IAM下,Wilcoxon 符号－秩检验中,德保矮马和云南矮马达到了显著性水平(P<0.05);在SMM下,宁强矮马在符号检验中达到了显著水平(P<0.05);在TPM下,5个群体均未达到显著水平(P>0.05)。因此,德保、云南和宁强矮马近期可能经历了瓶颈效应。本研究结果对中国矮马的保护和利用具有重大意义。     

Microsatellite-based genetic monitoring to detect cryptic demographic bottleneck in Indian riverine buffaloes (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>)

The present study was undertaken to evaluate different Indian riverine buffalo breeds (Bubalus bubalis) for mutation drift equilibrium and occurrence of any recent genetic bottleneck. A total of 330 animals from seven different breeds were analyzed with a set of 24 heterologous microsatellite markers. Three different tests revealed significant heterozygosity excess in all the seven buffalo breeds studied when assumed under infinite alleles model of microsatellite evolution, while it was the reverse with no significant heterozygosity excess when assumed under conservative stepwise mutation model. Under the two-phase model, all the buffalo breeds except Mehsana were found to be in mutation drift equilibrium when evaluated by all the three statistical methods. Standardized differences test and Wilcoxon signed-rank test revealed significant heterozygosity excess suggesting possible cryptic demographic bottleneck in Mehsana buffaloes of Western India.     

荧光标记微卫星分析广西树鼩群体的遗传多态性

选取10个微卫星位点,结合荧光标记(FAM) PCR扩增技术,运用毛细管电泳检测扩增产物,利用Microsatellite Toolkit、PopGene软件计算遗传相关指标,探讨广西树鼩群体的遗传多态性。结果发现,在10个微卫星基因座中,共检测到64个等位基因,平均等位基因数为6.4个,平均有效等位基因数为3.7892,平均观察杂合度和平均期望杂合度为0.6156和0.6963,平均多态信息含量为0.6367,其中7个是高度多态位点,3个属中度多态位点。此外,在10个微卫星基因座中,有5个位点偏离Hardy-Weinberg平衡(P<0.01)。结果表明广西树鼩遗传多态性较丰富,所选微卫星位点基本可用于评估广西树鼩群体遗传多样性。     

The Genetic Polymorphism Analysis in Tree Shrew(T.belangeri chinensis) based on Fluorescent Microsatellite

A total of 10 fluorescent labeling microsatellite markers detected by capillary electrophoresis were selected to analyze the genetic diversity of tree shrew(T.belangeri chinensis).Microsatellite Toolkit and PopGene softwares were used to calculate the genetic correlation indexes to assess the genetic diversity of the population.64 alleles with 6.4 alleles per locus were identified among 10 microsatellite loci.The average effective number of alleles, observed heterozygosity, expected heterozygosity and polymorphic information content were 3.7892, 0.6156, 0.6963, and 0.6367, respectively.Seven of all loci were high polymorphic, and three were moderate polymorphic.Five loci extremely significantly deviated from Hardy-Weinberg equilibrium(P<0.01).These novel polymorphic microsatellite markers indicated high genetic diversity, which will be used to evaluate genetic diversity in tree shrew.     

湘西黄牛遗传多样性的初步研究

利用6个微卫星标记对湘西黄牛的遗传多样性进行了初步分析.6对微卫星引物在湘西黄牛中共检测到65个等位基因,平均每对引物上检测到9.3个等位基因;平均有效等位基因7.8759个,等位基因在湘西黄牛群体中的分布很均匀;平均观测杂合度为0.8669,平均期望杂合度为0.8829.6个微卫星座位在湘西黄牛中平均多态信息含量(PIC)为0.8297,均大于0.5,都是高度多态性的.湘西黄牛杂合子的比例较大,基因纯合率都偏低,群体的遗传变异度高,表明湘西黄牛遗传多样性丰富,具有较大的选择潜力,可承受的选择压比较大,这是开展新品种培育工作的有利条件.     

4个肉牛品种微卫星多态性分析

本研究探讨了引进牛种（西门塔尔牛、利木赞牛）和山东地方黄牛（鲁西黄牛、利鲁牛）在20个微卫星位点上的多态性。试验从不同地区的种公牛站采集鲁西黄牛、利鲁牛、利木赞牛和西门塔尔牛的血液或精液样本,分别为56、27、31和30个,共计144个样本,血液样本采用Lab-Aid基因组DNA分离试剂盒提取基因组DNA,精液样本采用高盐法提取基因组DNA。利用20个微卫星标记,采用荧光标记毛细管电泳方法,对4个肉牛品种的DNA多态性进行分析,主要研究了每个群体的遗传变异指标（等位基因数、多态信息含量和杂合度）及群体间的遗传关系（F-统计量和基因流）。结果表明,肉牛基因组DNA条带整齐,无拖尾现象,质量较好,可用于本试验。20个微卫星座位中共检测到211个等位基因,平均等位基因数为10.6个。群体的平均观测杂合度在0.6147~0.7176之间,平均期望杂合度在0.6735~0.7862之间。在所有群体中各位点的多态信息含量在0.4853~0.8714之间,平均为0.7284,但在各个群体内的差异较大。近交系数及基因流分析结果表明,4个肉牛品种近交系数较低,群体间平均近交系数为0.085,每个微卫星位点的基因流均>1。总体来看,所选用的20个微卫星座位多态信息含量高,可作为有效遗传标记用于肉牛品种间遗传多样性分析。     

利用微卫星分析康西草原马匹种群的遗传多样性和群体结构

旨在揭示康西草原马匹的品种来源以及群体遗传结构。本研究采集了当地60匹健康状况良好、体重适中、3～6岁之间不区分公母马的血液样品,试验分为6个种群并以纯血马等4个国外马品种、1个我国地方马品种作为对照， 通过设计引物并提取基因组DNA结合微卫星扩增法对染色体上12个微卫星位点的等位基因进行检测，并对各种群遗传多样性参数、群体分化指数、瓶颈效应以及群体结构进行分析。试验按照群体个数为依据分为6组，每组1个重复，每个重复以该组样本量为标准。分析6个种群马的遗传参数结果表明，其中共检测到221个等位基因,平均Shannon指数为1.691；有效等位基因数(Ne)为3.649～5.397；期望杂合度(He)为0.681～0.798；观测杂合度(Ho)为0.632～0.780；平均多态信息含量(PIC)为0.643～0.772。这些结果表明，6个群体都具有很高的遗传多样性。通过微卫星DNA位点的连锁不平衡及哈迪-温伯格平衡分析发现， 大多数位点的P值都大于校正值(P=0.006 5)，表示较多位点都处于哈迪-温伯格及连锁平衡状态。各群体间群体分化系数(Fst)表明，群体间分化程度较低(Fst<0.15)。基于Nei’s遗传距离与地理距离之间Mantel相关性检验显示二者之间呈现正相关性(R=0.502)，但未达到显著水平(P=0.310)；各马匹种群瓶颈效应分析表明，P值极显著(P_(IAM)<0.01)说明该地区的马群体受到过瓶颈效应的影响且该马群体历史上数量有大规模的减少。通过 FCA因子分析、基于Nei’s标准遗传距离UPGMA树状图以及Structure贝叶斯聚类分析发现，该地区马种群与纯血马和温血马聚为一类，说明该种群最有可能主要来源于温血马和纯血马。这些结果揭示，康西草原地区马匹具有较高的遗传多样性，该地马群体的血统与纯血马和温血马相近，这为当地马遗传资源评估以及开发利用打下了坚实的基础。     

Screening the Polymorphic Tri-nucleotide Repeat Microsatellites from the Genome of Maiwa Yak and Their Genetic Diversity Analysis

In order to study the genetic diversity and differentiation characteristics of the existing population of Maiwa yak and provide a theoretical basis for utilization in the future, a total of 9 466 tri-nucleotide repeats microsatellites loci were screened based on the release of genome of yaks by bioinformatics method. The tri-nucleotide repeats microsatellites were amplified by PCR using the genomic DNA of 191 Maiwa yaks as templates,and the polymorphic microsatellite loci were genotyped through polyacrylamide electrophoresis experiment. After the Hardy-Weinberg equilibrium test, 5 tri-nucleotide microsatellite loci were deviated from the Hardy-Weinberg equilibrium (P <0.05). 15 microsatellite loci were highly polymorphic (PIC >0.5), the mean observed heterozygosity (Ho),mean expected heterozygosity(He) and mean polymorphic information content(PIC) were 0.5041,0.8152 and 0.7831,respectively. Maiwa yak population exhibited no characteristics of differentiation by Structure 3.0 software analysis. Therefore, Maiwa yak had plentiful genetic polymorphism while no signs of genetic differentiation were observed within the population.     

闽南黄牛的微卫星多态性研究

：用8个微卫星标记对闽南黄牛的等位基因频率、多态信息含量、杂合度和有效等位基因数等指标进行统计分析,并在此基础上对其进行聚类分析和分类研究。结果：8个微卫星标记在所检测的闽南黄牛群体中都表现出较丰富的多态性,在4个群体8个微卫星座位共有58个等位基因,每个微卫星标记平均检测到7．2个等位基因（3～11）;8个微卫星标记的平均多态信息含量（PIC）为0．6471,各群体的平均多态信息含量（PIC）差并不显著;全部群体平均杂合度为0．2930;各群体平均有效等位基因数为3．37。此表明闽南黄牛在微卫星位点上具有丰富的遗传多样性;根据奈氏标准遗传距离进行UPGMA聚类分析,结果表明4个群体间的遗传变异不大。     

麦洼牦牛基因组三碱基重复微卫星的挖掘及其遗传多态性分析

为了解麦洼牦牛现有群体的遗传多样性及种群遗传分化特征,试验通过生物信息学方法从已公布的牦牛基因组中筛选到9 466个三碱基重复微卫星位点,以191个麦洼牦牛基因组DNA样品为模板对各个位点进行PCR扩增和聚丙烯酰胺凝胶电泳基因分型。经过哈迪-温伯格平衡检验,在15个三碱基微卫星位点中,有5个位点偏离哈迪-温伯格平衡（P<0.05）。15个微卫星位点均为高度多态性（PIC>0.5）,群体平均观测杂合度（Ho）、平均期望杂合度（He）和平均多态信息含量（PIC）分别达到0.5041、0.8152和0.7831。进一步通过Structure 3.0软件分析发现,麦洼牦牛群体结构单一,无分化特征,表明麦洼牦牛品种虽然具有较高的遗传多态性但是无分化迹象。     

Genetic analysis of Mexican Criollo cattle populations

The objective of this study was to evaluate the genetic structure of Mexican Criollo cattle populations using microsatellite genetic markers. DNA samples were collected from 168 animals from four Mexican Criollo cattle populations, geographically isolated in remote areas of Sierra Madre Occidental (West Highlands). Also were included samples from two breeds with Iberian origin: the fighting bull (n = 24) and the milking central American Criollo (n = 24) and one Asiatic breed: Guzerat (n = 32). Genetic analysis consisted of the estimation of the genetic diversity in each population by the allele number and the average expected heterozygosity found in nine microsatellite loci. Furthermore, genetic relationships among the populations were defined by their genetic distances. Our data shows that Mexican cattle populations have a relatively high level of genetic diversity based either on the mean number of alleles (10.2-13.6) and on the expected heterozygosity (0.71-0.85). The degree of observed homozygosity within the Criollo populations was remarkable and probably caused by inbreeding (reduced effective population size) possibly due to reproductive structure within populations. Our data shows that considerable genetic differentiation has been occurred among the Criollo cattle populations in different regions of Mexico.     

A preliminary study of the genetic diversity of Xinjiang Tarim red deer (Cervus elaphus yarkandensis) using the microsatellite DNA method.

To evaluate the genetic diversity of the Xinjiang Tarim red deer (Cervus elaphus yarkandensis) population, we analyzed the frequencies of microsatellite alleles. Samples were collected from 3 isolated populations in Xaya, Lopnur and Qarqan of Xinjiang. Although 10 microsatellite loci were examined, alleles of 133 to 190 base-pairs were detected for only 3 loci: BM5004, BM4208 and BM888. The average observed multilocus heterozygosity was 0.08 +/- 0.04 for the Xaya, 0 for the Lopnur, and 0.17 +/- 0.08 for the Qarqan population. The average heterozygosity of all populations was 0.08 +/- 0.02. The observed heterozygosities were significantly lower than the expected values. The present results suggest that the bottleneck effect has occurred in the populations of the Xinjiang Tarim red deer.     

五指山猪小群体遗传学检测

本研究利用26个微卫星基因座对中国热带农业科学院热带作物品种资源研究所保种场的五指山猪小群体58个样本进行了遗传学检测,用非变性(中性)聚丙烯酰胺凝胶电泳检测微卫星的PCR扩增产物,统计了群体平均基因纯合率、等位基因数,利用等位基因频率计算出各群体的平均遗传杂合度(H)、多态信息含量(PIC)。统计结果:全群平均基因纯合率为66.5%;平均多态信息含量、平均观测杂合度为、平均期望杂合度分别为0.807、0.338、0.835;每个位点平均等位基因数为11.92,此结果说明该群体虽然近交程度较高,但仍具有丰富的遗传多样性,遗传变异较大。     

太湖鸡资源群体遗传变异的检测

应用微卫星标记对江苏省无锡市祖代鸡场有限公司太湖鸡的保种群体进行了遗传变异的分析,计算了群体的杂和度(H)和多态信息含量(PIC)。研究结果表明:30个微卫星标记在太湖鸡保种群体的杂和度为0.504～0.858之间,平均杂和度为0.688,群体的遗传多样性丰富;其中24个微卫星标记在太湖鸡中多态信息含量为高度多态,可作为有效遗传标记用于太湖鸡保种群的遗传分析,而且各座位杂和度的高低与PIC值的大小体现了较高的一致性。本研究结果为太湖鸡开发利用研究提供了基础,也为太湖鸡的合理保护提供了科学根据。     

早胜牛微卫星多态性及其与生长性状的关联分析

为了更好地了解早胜牛的遗传信息,为早胜牛的选育保种提供理论依据,本试验选取13对微卫星引物,应用PCR扩增和毛细管电泳的方法对48头早胜牛进行遗传多样性分析,并对13个位点不同基因型与早胜牛的初生重、6月龄重、成年体重、体高、体长、胸围和管围7个性状进行关联分析。结果显示,13个微卫星位点平均等位基因数目为9.54,平均有效等位基因数为4.792,平均观测杂合度为0.498,平均期望杂合度为0.783,平均多态信息含量为0.712。关联分析发现,与初生重存在关联的位点有D12S4和D15S10;与6月龄重存在关联的位点有D18S5和D12S4;与成年体重存在关联的位点有D14S31和D11S15;与体高存在关联的位点有D18S5、D15S10和D19S2;与体长存在关联的位点有D15S10、D14S31和D19S2;与胸围存在关联的位点有D18S5、D12S4和D19S2;与管围存在关联的位点有D18S5和D19S2。研究发现,选取的13个位点中存在关联的位点有6个：D18S5、D12S4、D15S10、D14S31、D19S2和D11S15。本试验所选微卫星位点在早胜牛群体中存在较丰富的多态性,并与经济性状具有关联性,可用于早胜牛遗传资源评价及早期选育改良。     

中国美利奴（新疆军垦型）种羊场超细品系核心群群体遗传结构分析

利用10个微卫星标记对新疆紫泥泉国家二级种羊场中国美利奴（新疆军垦型）羊超细品系核心群基因组DNA的遗传多样性进行了检测。统计了各位点的多态信息含量(PIC) 、遗传杂合度(H) 、有效等位基因数(E) 和基因纯合率(Rh)等遗传指标。结果表明：除BMS772（PIC=0.2567），BM6506（PIC=0.4697）为中度多态外，其余微卫星位点均为高度多态；群体的平均PIC、H、E、Rh分别为0.5848、0.6333、3.0315和0.4841，该品系核心群的基因纯合率处于中等水平，具有较为丰富的多样性；10个微卫星标记中只有OARAE57位点处于哈代 温伯格平衡(P>0.05)。     

中国美利奴(新疆军垦型)羊遗传多样性的微卫星分析

利用6个微卫星标记,采用PCR扩增,对200只中国美利奴(新疆军垦型)羊基因组DNA的遗传多样性进行了检测。统计了各位点的多态信息含量(PIC)、遗传杂合度(H)、有效等位基因数(E)和基因纯合率(Rh)等遗传指标。结果表明:除BMS772(PIC=0.2571)为中度多态外,其余微卫星位点均为高度多态;群体的平均PIC、H、E、Rh分别为0.5446、0.5684、2.5695和0.6165,此品种绵羊基因多态性和遗传多样性相对贫乏,而基因纯合率相对较高;只有BM6506位点处于哈代-温伯格平衡(P>0.05)。     

样本量和性比对微卫星分析中群体遗传多样性指标的影响

以4个中国地方鸡品种遗传多样性的微卫星分析数据为例,分析样本量和性比对微卫星分析中群体遗传多样性指标的影响。结果表明:当样本量超过20后,期望杂合度值趋于稳定,样本量与期望杂合度无显著相关,而与平均等位基因数呈正相关,在微卫星分析中性比对群体遗传多样性指标不表现出显著影响;微卫星位点多态性的高低直接影响到检测所需的样本量,在使用平均等位基因数分析群体遗传多样性时,应该充分考虑样本量对检测结果的影响;期望杂合度受样本量变动的影响较小,可作为度量群体遗传多样性的一个最适参数,而且样本量以20～25较为适宜。