大黄鱼快长相关微卫星标记的筛选与验证

为了筛选与大黄鱼生长性状紧密相关的分子标记,并对这些标记的有效性进行鉴定,研究以大黄鱼家系和群体为材料,经标记筛选、两次验证共三个步骤,找到2个与大黄鱼生长性状紧密相关的微卫星标记:LYC0088和LYC0143,其中LYC0088与体高、体质量均极显著相关（P0.01）,与体长显著相关（P0.05）,LYC0143与体长和体质量显著相关（P0.05）,与体高的相关性极显著（P0.01）。LYC0088与LYC0143位点的优势等位基因分别为E、A,优势等位基因型均为AB,优势等位基因型组合为AB/AB,两个位点呈加性效应。该结果为开展大黄鱼分子标记辅助育种提供了有价值的遗传标记。       

微卫星标记OarHH35,OarHH55和BM1329与乐至黑山羊产羔数相关性研究

根据微卫星标记在相近物种中具有高度保守性的特点,采用比较基因组学方法,初步探讨了3个与绵羊、山羊产羔率紧密相关的微卫星标记OarHH35、OarHH55和BM1329在4代85只乐至黑山羊中与其产羔数的相关性.结果显示微卫星标记BM1329在乐至黑山羊中可检测到的等位基因数为3,其片段大小分别为125、147和300 bp;标记OarHH55可检测到的等位基因数为2,片段大小分别为106和181 bp;标记OarHH35可检测到的等位基因数为3,片段大小分别为88、112和175 bp.统计分析表明,BM1329的300 bp等位基因和OarHH35的112 bp等位基因对乐至黑山羊产羔数呈正效应(P<0.05),而BM1329的147 bp等位基因和OarHH35的175 bp等位基因对产羔数呈负效应(P<0.05).因此,微卫星标记OarHH35和BM1329可作为乐至黑山羊高繁殖性能候选标记进行深入研究.     

大黄鱼微卫星标记的开发及其遗传方式分析

采用FIASCO方法构建大黄鱼(AC)n微卫星富集文库,从文库中随机挑选90个白色克隆,经过菌液PCR筛选得到60(66.7%)个阳性克隆进行测序,其中有56个克隆(93.3%)含有CA/GT重复数大于5的微卫星序列。56个微卫星序列中,二核苷酸微卫星51个(91.1%),三核苷酸微卫星5个;二核苷酸重复中有48个为(AC)n重复,占二核苷酸总数的94.1%。根据Weber的微卫星分类规则,完美型占75.0%,非完美型占8.9%,复合型微卫星占16.1%。共设计引物52对,在1个大黄鱼家系中35对引物所在位点具有多态性,28个(80.0%)位点子代基因型为1∶1∶1∶1(AB×CD/AB×AC)分离类型,6个位点属1∶1分离类型,1个位点属1∶2∶1(AB×AB)分离类型。35个位点中有32个位点的分离符合孟德尔分离比(P>0.05),另外3个位点(LYC0137、LYC0139、LYC0152)明显偏离1∶1或者1∶1∶1∶1的孟德尔分离比(P<0.05)。本研究开发的微卫星标记为大黄鱼微卫星遗传连锁图谱构建以及群体遗传学、分子进化和系统发育等研究提供了有用的分子工具。     

波尔山羊9个微卫星标记与产羔性状的关联研究

选择与绵羊高繁殖力主效基因FecB和FecX紧密连锁的5个微卫星标记BM1329, BM143, OarHH55, TGLA68和LSCV043, 和其他4个微卫星标记ETH225, INRA063, BM1225和MAF0214, 分析研究其与波尔山羊产羔数的关联。结果表明: 所研究的9个波尔山羊微卫星基因座均为高度多态性基因座(PIC > 0.5)。找到与波尔山羊产羔性状显著相关的等位基因计12个。其中与波尔山羊第一胎产羔数有显著正效应的等位基因3个: BM143的120 bp和108 bp, ETH225的183 bp; 与波尔山羊第一胎产羔数有显著负效应的等位基因8个: BM1329的216 bp、BM143的110 bp、BM1225的255 bp和239 bp、INRA063的175 bp、177 bp和189 bp, ETH225的163 bp。与波尔山羊第二胎产羔数有显著正效应的等位基因1个: TGLA68的115 bp。     

绵羊微卫星BMS2508和FecB基因的多态及连锁分析

文章分析与绵羊高繁殖力主效基因FecB紧密连锁的微卫星座位BMS2508在高繁殖力绵羊品种(小尾寒羊)和低繁殖力绵羊品种(特克塞尔、多赛特和中国美利奴)中的遗传多态性, 同时探讨该微卫星座位与小尾寒羊FecB基因的连锁不平衡关系。高繁殖力品种小尾寒羊在骨形态发生蛋白受体IB(Bone morphogenetic protein receptor IB, BMPR-IB)基因编码序列第746位碱基处发生了与Booroola Merino绵羊相同的FecB突变(A746G), 而在低繁殖力的特克塞尔、多赛特和中国美利奴绵羊中没有检测到该突变; 小尾寒羊BB、B+、++的基因型频率分别为0.485、0.398和0.117。微卫星座位BMS2508在4个绵羊品种的438个个体中共检测到8个等位基因和15种基因型, 最小等位基因为94 bp, 最大等位基因为116 bp; 小尾寒羊(n = 307)、特克塞尔(n = 45)、多赛特(n = 46)、中国美利奴(n = 40)和BB型(n = 149)、B+型(n = 122)、++型(n = 36)小尾寒羊群体中优势等位基因分别是100 bp、94 bp、94 bp、112 bp、100 bp、100 bp、112 bp, 其频率分别为0.453、0.544、0.802、0.475、0.483、0.439、0.389。连锁不平衡分析显示小尾寒羊FecB基因B等位基因与BMS2508微卫星座位100 bp等位基因之间存在一定的连锁不平衡(D′=0.408), 而+等位基因与BMS2508微卫星座位110 bp和114b p等位基因均存在一定的连锁不平衡(D′=0.513)。     

鲤鱼微卫星突变速率和模式(英文)

利用150个微卫星分子标记在F1代家系的基因型分析过程中,共有27600个等位基因从亲本向子代传递,其中在5个微卫星座位上检测到6个突变的等位基因。对突变的等位基因数目进行统计分析后得出:鲤鱼平均每个世代每个微卫星座位的突变速率为2.53×10-4。在发现突变的5个位点中,经测序发现,突变序列中插入1个以上的重复单元就导致了突变的发生。这些突变表明,鲤鱼的微卫星突变没有遵循严格的渐变突变模型(stepwise mutation model,SMM)。该文关于鲤鱼微卫星突变速率和模式的研究将会对统计鲤鱼有效群体的统计提供有效参数。     

中国龙虾微卫星标记的筛选及遗传多样性分析

文章以M13通用引物和重复序列(CT)₁₅、(AT)₁₅引物, 利用PCR法对中国龙虾(Panulirus stimpsoni Hoehuis)部分基因组DNA文库进行筛选。共获得78个微卫星序列, 分别分布于55个阳性重组克隆中, 其中完美型(perfect)共50个, 占64%; 非完美型(imperfect)3个, 占3.8%; 混合完美型(compound perfect)6个, 占7.7%; 混合非完美型(compound imperfect)19个, 占24.5%。根据微卫星序列, 设计并筛选出15对微卫星多态性引物, 对中国龙虾的群体进行了遗传多样性分析。获得3~12个等位基因, 等位基因大小在78~425 bp之间, 基本符合引物设计的理论长度。期望杂合度范围为0.48~0.87, 平均值为0.71, 表明中国龙虾基因组微卫星具有较高的杂合度与遗传多样性。15个微卫星位点的PIC值从0.44到0.84, 平均值为0.60, 说明这些微卫星位点在中国龙虾基因组中包含丰富的遗传信息, 合适用于中国龙虾的各种分子标记及遗传学分析和应用。     

猪PAC克隆的微卫星DNA分离研究

利用(CA)8核心序列,设计锚定引物,采用直接测序法,从单个猪PAC克隆中分离到一个新微卫星DNA。根据该微卫星DNA的侧翼序列,设计了专一引物,在8个猪种40个个体中检测到3个等位基因,片段长度分别为305 bp、307 bp和309 bp。3种等位基因纯合子个体的PCR产物序列分析表明,这3种等位基因分别有12、13和14次CA双核苷酸重复。 Abstract:A novel microsatellite DNA was isolated from a single porcine PAC clone by sequencing the PAC clone directly with (CA)n repeat motif anchored primer.The specific primer pairs flanking the (CA)n repeat region were used to amplify the genomic DNA of 40 individuals from 8 pig breeds,which detected three alleles with the fragment length of 305 bp,307 bp and 309 bp.The PCR product sequencing results of homozygous animals representing three alleles revealed that those three alleles contained 12,13 and 14 CA dinucleotide repeats respectively.     

大黄鱼肌肉生长抑制素基因微卫星序列多态性分析

肌肉生长抑制素(myostatin,MSTN)参与肌肉生长和脂肪发生的调节．本研究在克隆大黄鱼MSTN cDNA的基础上,对3′端非编码区微卫星序列的多态性及其与体长、体重和肌肉脂肪含量的关系进行了分析．结果表明,获得的cDNA长1 886 bp,在3′端非编码区存在微卫星序列（CA）_n．在受检的52个个体中,微卫星序列长度在64～126 bp之间.大部分个体的微卫星序列内存在碱基替换,最常见的碱基替换形式是C→T,属于非完美型微卫星序列．根据该位点微卫星序列长度,在实验群体中共检测到23个等位基因,其中频率为0.019 2的等位基因11个,0.038 5的5个, 0.076 9的3个,0.057 7的2个,0.115 4和0.134 6的各1个．该基因位点的群体杂合度为0.932 7,多态信息含量为0.928 8．微卫星序列长度与大黄鱼体长、体重和肌肉脂肪含量之间的相关系数分别为0.409、0.435和-0.026,P值分别为0.021、0.016和0.878．碱基替换对大黄鱼生长及肌肉脂肪含量均无显著影响．     

意大利蜜蜂产浆性状10个微卫星位点的遗传分析

我国培育成功的世界上蜂王浆产量最高的蜂种（Ea）是从20世纪30年代引进我国的意大利蜜蜂（Eb）中选育的。采用10个微卫星位点对蜂王浆高产蜜蜂、原种意大利蜜蜂（Ee）和本地意大利蜜蜂进行研究,以探明由于人工选择和地理隔离造成的其分子进化上的一些特征。结果,10个微卫星位点在3个蜂种中共扩增到96个等位基因,其中有48个等位基因是不同的,表明10个微卫星位点在3个蜂种中的高度多态性,而且由于人工选择和地理隔离已造成3蜂种在遗传基础上的一些分化。3蜂种的多态信息含量（PIC）分别为0．57、0．50、0．57,杂合度分别为0．60、0．57、0．61,二者均无显著差异。遗传距离的分析结果显示,Ee和Eb（0．14）、Eb和Ea（0．16）之间的遗传距离较近,而Ea和Ee（0.25）之间的遗传距离较远。等位基因频率的分析结果表明,6个位点的7个等位基因的频率（A29的159bp、A24的100bp和104bp、A7的110bp、A43的126bp、A14的221bp和A113的221bp）以Ee、Eb、Ea的顺序递增,Ea的这7个等位基因频率分别显著高于Ee和Eb。同时4个位点的4个等位基因的频率（A24的106bp、A43的140bp;A113的215bp和A14的219bp）以Ea、Eb、Ee的Ⅲ页序下降,Ea在这4个位点的频率分别显著低于Eb和Ee。这些位点的等位基因可能与蜂王浆产量有关。     

Analysis of Genetic Diversity in the North Eastern Himalayan Maize Landraces using Microsatellite Markers

Population DNA fingerprinting of 48 selected North Eastern Himalayan (NEH) landrace accessions was undertaken using 41 polymorphic fluorescent dye-labelled microsatellite/Simple Sequence Repeat (SSR) markers, using a DNA Sequencer. The analysis revealed a large number of SSR alleles (576), with high mean number of alleles per locus (13.8), and Polymorphism Information Content (PIC) of 0.63, reflecting the level of diversity in the NEH accessions and the informativeness of the SSR markers. The study also led to identification of 135 unique alleles, differentiating 44 out of the 48 accessions. Five highly frequent (major) SSR alleles (umc1545 _80bp, phi062 _162bp, umc1367 _159bp, umc2250 _152bp and phi112 _152bp) were detected indicating that chromosomal regions harbouring these S SR alleles might not be selectively neutral. Analysis of population genetic parameters, including Wright’s F statistics, revealed high level of genetic differentiation, very low levels of inbreeding, and restricted gene flow between the NEH landraces. AMOVA (Analysis of Molecular Variance) showed that 67 per cent of the total variation in the accessions could be attributed to within-population diversity, and the rest between the accessions. Cluster analysis of SSR data using Rogers’ genetic distance and UPGMA, showed significant genetic diversity among the landraces from Sikkim. This is the first detailed study of SSR allele frequency-based analysis of genetic diversity in the NEH maize landraces of India.     

Isolation and characterization of 11 microsatellite markers for the large yellow croaker, Pseudosciaena crocea

A new set of 11 microsatellite markers was isolated and characterized in the large yellow croaker (Pseudosciaena crocea Richardson) from a CA-enriched genomic library. Of 35 microsatellite markers screened, 11 microsatellite markers are highly polymorphic in one hatchery stock which contained 58 individuals. The high genetic variability was represented mainly by the number of alleles, which ranged from 7 to 16, and the observed heterozygosity, which ranged from 0.43 to 0.79. These newly isolated markers increase the available molecular resources that can be used to analyze genetic diversity and population structure of large yellow croaker.     

Sampling for Microsatellite-Based Population Genetic Studies: 25 to 30 Individuals per Population Is Enough to Accurately Estimate Allele Frequencies

One of the most common questions asked before starting a new population genetic study using microsatellite allele frequencies is “how many individuals do I need to sample from each population?” This question has previously been answered by addressing how many individuals are needed to detect all of the alleles present in a population (i.e. rarefaction based analyses). However, we argue that obtaining accurate allele frequencies and accurate estimates of diversity are much more important than detecting all of the alleles, given that very rare alleles (i.e. new mutations) are not very informative for assessing genetic diversity within a population or genetic structure among populations. Here we present a comparison of allele frequencies, expected heterozygosities and genetic distances between real and simulated populations by randomly subsampling 5–100 individuals from four empirical microsatellite genotype datasets (Formica lugubris, Sciurus vulgaris, Thalassarche melanophris, and Himantopus novaezelandia) to create 100 replicate datasets at each sample size. Despite differences in taxon (two birds, one mammal, one insect), population size, number of loci and polymorphism across loci, the degree of differences between simulated and empirical dataset allele frequencies, expected heterozygosities and pairwise F_ST values were almost identical among the four datasets at each sample size. Variability in allele frequency and expected heterozygosity among replicates decreased with increasing sample size, but these decreases were minimal above sample sizes of 25 to 30. Therefore, there appears to be little benefit in sampling more than 25 to 30 individuals per population for population genetic studies based on microsatellite allele frequencies.     

Eleven microsatellite loci for the saddleback clownfish Amphiprion polymnus

We report nine (CA)_12?49, one (GATA)₃₉, and one (TCTA)₂₆ microsatellite loci for the saddleback clownfish Amphiprion polymnus, isolated using an enrichment cloning procedure. A large number of alleles (range 6–30), and high levels of observed heterozygosity (mean = 0.6810) were resolved in 100 individuals of a single population, indicating that these markers should be useful to assess genetic structure and population dynamics over fine spatial scales.     

Isolation and characterization of six microsatellite markers in the large yellow croaker (Pseudosciaena crocea Richardson)

Six polymorphic microsatellite markers were isolated and characterized using an enriched library technique in the large yellow croaker (Pseudosciaena crocea Richardson, 1864), a commercially important marine fish in China. They showed PIC (polymorphism information content) ranging from 0.064 to 0.885 (average of 0.580) and allele numbers ranging from two to 13 (average of 7.5), which were useful for the studies on population genetics and selective breeding of the large yellow croaker.     

Development of thirty-five novel polymorphic microsatellite markers in Pseudosciaena polyactis (Perciformes:Sciaenidae) and cross-species amplification in closely related species,Pseudosciaena crocea

Small yellow croaker, Pseudosciaena polyactis, is an economically important marine fishery species. In this study, we isolated 35 novel polymorphic microsatellite primers in P. polyactis by using the combined biotin capture method. The polymorphism of each locus was assessed in 30 individuals from Donggang, Northern Yellow Sea, China. A total of 519 alleles were detected and the number of alleles per locus ranged from 3 to 23. The PIC values of these 35 microsatellite loci ranged from 0.367 to 0.940. The observed (H_o) and expected heterozygosity (H_e) per locus ranged from 0.233 to 1.000 and from 0.438 to 0.943, respectively. Seven loci significantly deviated from Hardy–Weinberg equilibrium (HWE) after Bonferroni correction and no significant linkage disequilibrium (LD) was found between pairs of loci. In addition, cross-species amplification was performed in Pseudosciaena crocea, a closely related species of P. polyactis, to assess the applicability of these markers. These polymorphic microsatellites will provide useful tools for the study of genetic diversity and population structure of P. polyactis and P. crocea.     

Assignment of the gene for porcine insulin-like growth factor 1 (IGF1) to chromosome 5 by linkage mapping

Investigation of published sequence data from the porcine insulin-like growth factor 1 (IGF1) gene, resulted in the detection of a microsatellite in the first intron of the gene. Polymerase chain reaction (PCR) primers flanking the (CA)₁₉ repeat were constructed. Polymorphism and Mendelian segregation were documented in a three-generation pedigree and allele frequencies were determined in 74 unrelated animals from four different breeds. Seven alleles were encountered. Linkage analysis was performed in a large pedigree established for gene mapping. Linkage between the IGF1 microsatellite and an anonymous microsatellite marker, S0005, was detected. Furthermore, IGF1 and S0005 was found to be linked to the porcine submaxillary gland mucin (MUC) gene, previously assigned to chromosome 5. The results presented here extend the linkage group on pig chromosome 5 and are in accordance with conserved synteny between human chromosome 12, cattle chromosome 5, mouse chromosome 10 and pig chromosome 5.     

Development of a robust marker for <Emphasis Type="Italic">Psy-1</Emphasis> homoeologs and its application in improvement of yellow pigment content in durum wheat

Phytoene synthase-1 (Psy-1) homoeologs are associated with yellow pigment content (YPC) in endosperm of durum and bread wheat. In the present study, microsatellite variation in promoter region of Psy-A1 was identified in durum wheat and marker Psy-1SSR, targeting the microsatellite variation was developed which amplifies variation in Psy-A1 and Psy-B1 loci simultaneously. Psy-A1SSR was mapped within QYp.macs-7A, a major QTL for YPC identified earlier in PDW 233/Bhalegaon 4 population. Marker Psy-A1SSR was further validated in two different RIL populations and a set of 222 tetraploid wheat accessions including less cultivated tetraploid wheat species. Eight alleles of Psy-A1SSR were identified in 222 wheat accessions, while seven alleles were observed for Psy-B1SSR. Variation at Psy-A1SSR showed significant association with YPC, whereas no association was observed with Psy-B1SSR. Marker-assisted introgression of Psy-A1SSRe allele from PDW 233, to durum wheat cultivars MACS 3125 and HI 8498 resulted in improvement of YPC. Backcrossed BC₃F_2:4 and BC₂F_2:3 lines selected using Psy-A1SSR showed 89 to 98% gain in YPC over recurrent parents indicating robustness of marker. The marker can thus be utilized in marker-assisted improvement of YPC in durum wheat cultivars.     

Ten novel microsatellite markers for the freshwater sleeper Micropercops swinhonis (Günther, 1873), with testing of cross‐species amplification in two other fishes from suborder Gobioidei

Ten novel polymorphic microsatellite loci were developed for the freshwater sleeper Micropercops swinhonis, a relatively abundant and broadly distributed lake‐dwelling fish in Asia, using next generation sequencing. These markers were tested in a population of 48 individuals, and characteristics suggest that they may be useful for population genetic studies. The average number of alleles per marker was 6.6 (range: 2–26), the average expected heterozygosity was 0.55 (range: 0.081–0.955), and the average polymorphic information content value per marker was 0.507 (range: 0.077–0.942). No marker showed significant deviation from Hardy‐Weinberg Equilibrium following Bonferroni correction of significance values, and no markers showed evidence of null alleles, large allele dropout, or scoring errors from stutter bands. Two markers had successful amplification in Odontobutis potamophila, and one marker had successful amplification in Rhinogobius giurinus. These novel markers may be useful for further research in population genetic studies involving M. swinhonis.