微卫星标记及其在牛遗传育种中的应用

微卫星标记技术是目前在动物遗传标记研究中运用较广泛的一种分子标记技术，本文介绍了微卫星标记技术的基础理论及分析方法，并对其在牛遗传育种研究中的应用进行阐述。     

Molecular Mapping of QTLs for Cold Tolerance at the Budburst Period in Rice

The quantitative trait loci (QTLs) for cold tolerance at the budburst period (CTBP) was identified using a F2:3 population including 200 lines derived from a cross of indica and japonica Milyang23/Jilengl. A molecular linkage map of 97 SSR markers was constructed using interval mapping and covered a total length of 1 357.3 cM with an average distance of 13.99cM, between adjacent markers in rice genome. The CTBP of F3 lines was evaluated at 5℃, and the survival seedling rate after treating under low temperature at the budburst period was used as cold tolerance index for CTBP. A continuous distribution near to normal for CTBP was observed in F3 lines, CTBP is a quantitative trait which was controlled by some genes. Three QTLs on chromosomes 2, 4 and 7 which are associated with CTBP were detected on location of RM6-RM240, RM273-RM303, RM214-RMll, respectively,which explained the range of the observed phenotypic variance from 11.5 to 20.5%. qCTBP4detected on RM273-RM303 of chromosome 4 explained 20.5% of the observed phenotypic variance. The effect of qCTBP4's allelic gene comes from Jileng 1.     

随机扩增微卫星DNA多态标记(RAMPs)及其应用

随机扩增微卫星DNA多态标记是在微卫星DNA基础上衍生出的一种新型分子标记。它综合了微卫星DNA和随机扩增多态DNA（RAPD）两种标记的优点，可用来快速检测动植物群体的遗传变异及分离新的微卫星DNA。本文介绍了随机扩增微卫星DNA多态标记的种类及其应用。     

三种微卫星DNA标记在奶牛中的应用

选择了分布在牛的3条染色体上的3个微卫星DNA标记UWCA9、BM3413、IDVGA-2,分析其在所供牛群体中的多态分布情况。结果表明,每个位点的等位基因个数及多态信息含量值分别为4/0.70、5/0.75和6/0.80。经分析各标记位点均符合孟德尔遗传规律。     

Standardization of a set of microsatellite markers for use in cultivar identification studies in olive (Olea europaea L.)

The comparability of eight olive microsatellite profiles in 17 cultivars generated by four laboratories using different DNA genotyping platforms was tested. In total, 54 alleles were identified, from a minimum of 3 alleles (DCA15) to a maximum of 12 (DCA9), averaging 6.75 alleles per marker. A representative sample of the olive genetic variability can be obtained by selecting a relatively low number of sufficiently different cultivars. Initial comparison of the data generated, revealed the presence of a few discrepancies between the laboratories, most of them due to easily identifiable rounding errors. However, 94.9% of the genotypes were in agreement between at least two laboratories after the harmonisation of the results and only in seven cases it was not possible to determine the genotype. No discrepancies between the four laboratories were observed at all in 106 genotypes (77.9%), while 18 (13.2%) showed discrepancies at one allele and 12 (8.8%) at two alleles. Most of the differences (73.8%) were due to results obtained by only one different laboratory each time. Markers DCA3, DCA8, DCA11, DCA13, DCA14 and DCA15 showed the highest concordance percentage between datapoints scored from all partners, while DCA4 and DCA9 produced less concordant results. Forty-three percent of the discrepancies were due to heterozygous/homozygous misreadings, that is often related to the presence of stutter peaks. The determining factors for obtaining reproducible results seem to be the utilization of unique sources of plant material, the employment of the same reference cultivars by all the laboratories, the standardization of PCR conditions and the selection of the markers with the most robust amplification pattern.     

Population genetic structure of Orchesella cincta (Collembola; Hexapoda) in NW Europe, as revealed by microsatellite markers

We studied genetic variation and population differentiation in the springtail Orchesella cincta L. An earlier approach, using allozymes, revealed extremely low variation among and within populations from NW Europe. Microsatellite marker analysis showed higher genetic variation than allozymes, and agreed with the previously reported low population differentiation in the species. Analysis of molecular variance showed that genetic variation within populations amounted to 96.5% of the total variation, whereas the remaining 3.5% is accounted for by population differentiation. Population differentiation, as described by microsatellite markers and with the exception of one population, can be explained by an isolation by distance. Although the microsatellites are short, viz. only up to 12 repeat units, they appear to be useful tools in revealing population genetic structures in O. cincta.     

利用微卫星标记对两个世代百宜黑鸡遗传多样性的研究

采用微卫星标记对百宜黑鸡第4、第5世代的遗传多样性进行研究，结果表明：10个微卫星座位在百宜黑鸡群体中的等位基因频率变化范围较大，为0．0124-0．4876。百宜黑鸡第4世代和第5世代的多态信息含量（PIC）分别为0．6649和0．6418，呈高度多态（PIC〉0．5），说明百宜黑鸡第4世代和第5世代均有丰富的遗传多样性。     

Polymorphism Analysis of Microsatellites Associated with Seven Candidate Genes for Equine Cryptorchidism

Association of seven candidate genes with cryptorchidism was investigated in the Thoroughbred. A pedigree composed of 23 cryptorchids and 24 nonaffected horses, sharing a common ancestor, was constituted. Sixteen microsatellite markers were developed either from bacterial artificial chromosomes (BAC) isolated for each candidate gene or by in silico screening. DNA from our pedigree was genotyped for these microsatellites. Statistical analysis of the allelic and genotypic frequencies observed with these markers did not reveal any association between the candidate genes and the cryptorchidism phenotype in our horse panel.     

灰盖鬼伞基因组中微卫星序列的组成

本研究利用已公布的灰盖鬼伞基因组测序结果,对该真菌基因组中的微卫星(microsatellite)或简单重复序列(simplesequence repeats,SSRs)进行了系统分析。结果表明,在已公布的36.2 Mb的基因组序列中,共有7 859个SSR序列(长度大于15bp,匹配值大于80%)。SSR的碱基总数达143 kb,约占整个基因组碱基数的0.40%,平均4.61 kb中就有1个大于15 bp的SSR序列。其中数量最多的是3碱基SSR,数量达到3 033个,其次为6碱基重复序列(2 121个)、5碱基重复序列(1 820个),这3种SSR总数达6 974个,占SSR总数的84.9%,单碱基重复序列数量最少,仅有285个。与子囊菌中的稻瘟病菌和粗糙脉孢菌相比,灰盖鬼伞菌基因组中每百万碱基中的SSR数量和密度都较小。这些研究结果可为该担子菌基因组的特征描述、注释及分子标记的筛选提供基础信息。     

4对微卫星DNA标记在3个绵羊品种中多态性的研究

选用无角道塞特、萨福克与中国美利奴肉羊品种群体,耳组织提取基因组DNA,用4对微卫星引物进行PCR扩增,通过电泳分型、凝胶成像系统分析各位点等位基因及全部个体的标记基因型,计算基因频率、多态信息含量(PIC)和杂合度等,从分子水平上分析4个位点的遗传多态性.结果表明,CSSM18,OB2,MCM38,MCMA26这4个位点的等位基因数分别为14、15、13、13,多态信息含量(PIC)丰富,杂合度高,均属于高度多态性位点,用于作为与生产性能相关的遗传标记是较理想的.