绵羊3号染色体的遗传连锁图谱构建及QTL定位

以四川凉山半细毛羊资源群体为研究对象, 选取位于绵羊3号染色体上的9个微卫星标记, 构建遗传连锁图谱, 用QTLExpress软件对影响绵羊生长发育的5个性状进行QTL定位分析。结果显示: (1) 9个微卫星标记的平均多态信息含量和平均群体杂合度分别为0.606 (0.378～0.738)、0.650 (0.404～0.766); (2) 连锁图谱总长为339.8 cM, 标记平均间距为42.5 cM, 略长于国际主要绵羊作图组织构建的图谱; (3) QTLExpress分析表明, 检测到影响羔羊断奶重、断奶日增重和成年体重的3个QTL, 分别位于99 cM、219 cM、273 cM处, 影响断奶日增重和成年体重的QTL都达到显著水平, 而影响羔羊断奶重的QTL未达到显著水平。     

利用鸡F2资源群体构建1号染色体遗传连锁图谱

在鸡1号染色体上选取23个微卫星标记,利用东北农业大学鸡F2资源群体构建了遗传连锁图谱。选用369只F2个体用于基因型测定。结果表明23个微卫星位点除MCW0058为低度多态,其他位点均为中高度多态。构建的连锁图谱覆盖1号染色体全长,总共637.9 cM。MCW0115和ROS0025标记顺序与EL图谱不同,但与WAU图谱一致。其他标记顺序与3大参考家系标记顺序一致,图谱总长和标记间距离大于3大参考家系。此连锁图谱的构建为数量性状位点（QTL）定位奠定了良好的基础。     

猪1、3号染色体微卫星位点多态性及遗传连锁图谱的构建

利用 3头英系大白猪和 7头梅山猪为父母本建立了F2 参考家系。F1 公猪 5头 ,母猪 2 3头 ,随机交配产生 147个F2 个体。根据美国肉畜研究中心 (USDA MARC)公布的猪遗传连锁图谱 ,在 1号和 3号染色体上等间隔 (2 0cM)选择 8个和 9个微卫星标记 ,对参考家系全部的F0 、F1 和F2 个体进行扩增 ,获得各标记位点基因型。研究结果表明 ,等位基因数介于 2到 5之间 ,平均每位点 3.35个等位基因 ;部分等位基因片段长度超过USDA MARC所报道的结果。标记位点杂合度为 0 .385 3～ 0 .70 97,平均 0 .5 795。有信息的减数分裂数为 35～ 30 5 ,平均 2 40。利用此参考家系和CRI MAP软件包构建的 1号和 3号染色体图谱分别长 182 .3cM和 180 .2cM。 1号染色体的母畜图谱短于公畜图谱 ,而 3号染色体正好相反。与USDA MARC报道相比较 ,微卫星排列顺序与报道相同 ,但 1号染色体长 44 .8cM ,3号染色体长 6 3.3cM。此连锁图的构建为以后的数量性状基因位点 (quantitativetraitloci,QTLs)定位奠定了基础。     

猪3号染色体九个微卫星位点的遗传多态性研究和遗传图谱构建

从已公布的猪 3号染色体连锁图谱中选取 9个微卫星位点 ,分析了这些位点在大白猪×梅山猪资源家系F2代 140头个体上的多态性 ,利用Crimap软件分别构建了猪 3号染色体两性平均连锁图谱以及公、母畜连锁图谱。结果表明 :各位点等位基因数为 2～ 4个 ,杂合度为 0 .436～ 0 .6 5 6 ,多态信息含量为 0 .35 1～ 0 .5 82 ;本研究所构建的平均连锁图谱全长为 16 1.1cM ,公、母畜连锁图谱全长分别为 135 .8cM和 188.7cM。与USDA所公布的连锁图谱相比 ,两者的标记顺序一致 ,但我们的图谱标记间隔偏大。     

中国美利奴(新疆军垦型)绵羊9个微卫星基因座多态性研究

利用PCR技术和复合电泳银染技术检测中国美利奴(新疆军垦型)绵羊第1号染色体上BM6506,BM1824,BM6438, ILSTS004和OarDB6 等5个基因座和第6号染色体上 BM4621,OarHH55,BM143和OarJMP8 等4个基因座,共9个基因座的基因频率（Pi）、个体鉴别力（DP）、杂合度（H）、多态信息含量（PIC）、和非父排除概率（PE）。结果显示：9个微卫星基因座的基因型分布符合Hardy-Weinberg平衡,绵羊中9个微卫星基因座中BM4621 基因座的DP、H、PIC和PE都为最高。9个微卫星基因座的累积个体鉴别力(CDP)为0.99999,累积非父排除能力(CPE)为0.99915。结果显示9个微卫星基因座适用于中国美利奴(新疆军垦型)绵羊的遗传连锁分析、个体识别和亲权鉴定等研究领域。     

猪F2设计资源家系中4条染色体微卫星标记分析

利用中国地方猪种蓝塘猪(16头母猪)与外来品种长白猪(8头公猪)按F2设计建立资源家系, 根据美国肉畜中心(USDA-MARC 2.0)公布的猪连锁图谱, 在1、4、7和8号染色体上间隔10~20 cM选择一个微卫星标记, 共31个标记, 采用WAVEÒ核苷酸片段分析系统和ABI 377 DNA序列分析仪检测资源群体的P、F1和F2代个体微卫星的基因型, 对其基因频率、杂合度和多态信息含量等进行统计分析。结果发现: 利用ABI 377检测的猪1、4和8号染色体上的有效微卫星标记21个, 其中13个标记的18个等位基因片段大小超过了网上已报道的结果, 发现新等位基因的标记占62%; 在31个微卫星标记中, 杂合度(h)在0.043~0.7855之间, 总平均杂合度为0.6460, 其中70%座位的h>0.60; 总平均多态信息含量(PIC)为0.5949, 有77.4%位点的PIC>0.5。统计分析结果表明, 选用的微卫星标记能够较好地提供标记信息, 为进一步在该家系中进行猪重要性状的QTL定位打下了良好的基础。     

微卫星DNA和AFLP标记在水稻分子标记连锁图上的分布

以一个栽培稻（ＯｒｙｚａｓａｔｉｖａＬ．ｓｐ．ｉｎｄｉｃａ）和野生稻（Ｏ．ｒｕｆｉｐｏｇｏｎＧｒｉｆ）杂交的Ｆ２作图群体以及由该群体构建的ＲＦＬＰ标记连锁图,分析了微卫星ＤＮＡ和ＡＦＬＰ标记的多态性、遗传行为及其在染色体上的分布。共定位了２８个微卫星ＤＮＡ标记和１７２个ＡＦＬＰ标记。２８个微卫星ＤＮＡ标记中有６个为华中农业大学作物遗传改良国家重点实验室根据数据库中序列而设计,其余２２个来自美国Ｃｏｒｎｅｌ大学已发表的结果。１７２个ＡＦＬＰ标记出自２５对引物扩增得到的２２８个多态性带的片段。这些标记分布于水稻的１２条染色体。将此２００个ＰＣＲ标记与华中农业大学作物遗传改良国家重点实验室构建的ＲＦＬＰ连锁图整合,得到一张含６１２个分子标记位点的遗传连锁图。     

连续近交下家猪微卫生基因组杂合度与经济性状的相关性研究

从已这位于家猪０１、０２、１１、１３、１７、１８号染色体上的遗传标记中选用５６个具有足够覆盖率的微卫生标记,对１个连续５个代近交家系共１９２个头家猪进行了基因组扫描.平均微卫生标记杂合度估计基因组杂合度（ＧＨ）。ＧＨ对于屠宰重（ＳＷＴ）和日均屠宰重（ＡＤＳＧ）为显著正相关效应,对于背膘厚（ＢＦＤＰ）的相关效应不显著且方向也不一致。ＧＨ的相关效应随近交世代递增而呈非线性变化趋势;ＧＨ对于ＳＷＴ和ＡＤＳＧ的相关效应在近交前２世代呈上升趋势。２代分别到达最大值（２２．４３kg和０．１３２kg/d）,此后随近交世代的递增而递减;ＧＨ对于ＢＦＤＰ的相关效应随世代递增而非线性递减。微卫星杂合度的相关效应在不同染色体间存在较大差异,对ＳＷＴ和ＡＳＤＧ均表现为正效应,其中又以１３号染色体标记杂合度的相关效应为最大（６．３０kg和０．０３２kg／d)其次依镒为１号、１７号、１８号、２号和１１号。各染色体微卫星标记杂合度对于ＢＦＤＰ的相关效应估值的标准误差大,且效应方向不一致（１８号染色体来正效应,其余染色体为负效应）,由引得到如下３点启示,第一,对于经济性状重要的基因（e.g.QTL)不同是均衡分布于各杂染色体上,此差异可能反应出生物性状决定在染色体以及分子分上上的差异;第二,由于基因,基因互作和且背景效应的复杂性,基因（组）杂合度与性能间不为简单的相关,学可能由于标记数目不够或是标记选择不适当而误导;第三,由于高度近交（如连续同胞交配）下较高的连锁不平衡所致,有害基因可能以较高的概率民中性标记连锁遗传,由此可能部分或全部抵消杂合优势的表现,甚至出现杂合劣势。     

用商品群作为参考系构建猪的微卫星连锁图谱

由 19头杂种公猪 [皮特兰× (皮特兰×汉普夏 ) ]、5 2头杂种母猪 [Leicoma× (大约克×长白 ) ]及其 332头后代组成的商品群作为参考系 ,选择 172个微卫星标记和 3个Ⅰ类标记 (RYR1、PIT1、PRKAG3)对参考系的个体进行遗传标记分型 ,应用CRIMAP(2 4 )构建猪的整个基因组微卫星连锁图谱。采用多重PCR方法对微卫星标记进行扩增 ,用ABI 377测序仪进行电泳分离 ,应用Genescan 3 0和Genotyper 2 0软件进行基因型检测。 3个Ⅰ类标记用PCR RFLP技术进行分型。CRIMAP程序分析表明 :所构建的猪常染色体性平均连锁图谱的总长度为 2 36 8 7cM ,X染色体的长度为 14 3 10cM ,遗传标记的平均间距为 16 3cM ,亲本的微卫星标记座位的杂合度平均为 0 70。此连锁图谱的构建将为商品猪群的生长、胴体、肉质以及繁殖性状的QTL扫描打下基础。     

采用6个微卫星位点研究6个绵羊品种遗传多样性

利用6个微卫星座位对中国乌珠穆沁羊、小尾寒羊、滩羊、昭通绵羊、呼伦贝尔羊和甘肃高山细毛羊6个绵羊品种,共计280个个体进行遗传多样性分析。计算了6个绵羊品种间的多态信息含量、杂合度和遗传距离,并进行了主成分分析和UPGMA聚类。发现了101个等位基因,平均杂合度0.599-0.691,平均多态信息含量0.609-0.680;甘肃高山细毛羊与其他绵羊品种遗传分歧最大,而呼伦贝尔羊与乌珠穆沁羊间的分歧最小。结果表明6个绵羊品种均具有较高的遗传多样性,品种间的遗传关系与其形成历史、分化及地理分布基本一致。     

Molecular cloning and mapping of the bovine and ovine skeletal muscle-specific calpains

The coding regions of the bovine and sheep skeletal muscle-specific calpains (CANP3 or p94) were cloned and sequenced by RT-PCR. Direct sequencing confirmed open reading frames of 2466 bp for both species, and bovine and sheep CANP3 shared 98.5% identity in their amino acid code. These sequences were greater than 88% identical to human, pig, rat and mouse CANP3 nucleotide sequences, and greater than 93% identical for the amino acid code. Single nucleotide polymorphisms were used to map the bovine and sheep CANP3 genes in two steps. The genes were placed into linkage groups based on two-point LOD scores (> or = 3.0) and the best order was determined with multipoint linkage analysis (CRI-MAP vs. 2.4). Bovine CANP3 mapped to bovine chromosome 10, relative position 33.9 CM with linkage to nine markers; LOD scores ranged from 4.89 to 8.61 (order, BMS2349-BL1035-RME25-CANP3-BM6305-BMS86 1-ILSTS053-BMS2742-CA090-BMS529). Ovine CANP3 mapped to chromosome 7, relative position 58 CM, with linkage to only one marker, BMS861 (a bovine microsatellite that has been used in sheep), with no recombination and a LOD score of 5.72. The observed heterozygosity was 50% for both CANP3 markers in bovine and sheep pedigrees.     

A second-generation linkage map of the sheep genome

A genetic map of Ovis aries (haploid n = 27) was developed with 519 markers (504 microsatellites) spanning ∼3063 cM in 26 autosomal linkage groups and 127 cM (female specific) of the X Chromosome (Chr). Genotypic data were merged from the IMF flock (Crawford et al., Genetics 140, 703, 1995) and the USDA mapping flock. Seventy-three percent (370/504) of the microsatellite markers on the map are common to the USDA-ARS MARC cattle linkage map, with 27 of the common markers derived from sheep. The number of common markers per homologous linkage group ranges from 5 to 22 and spans a total of 2866 cM (sex average) in sheep and 2817 cM in cattle. Marker order within a linkage group was consistent between the two species with limited exceptions. The reported translocation between the telomeric end of bovine Chr 9 (BTA 9) and BTA 14 to form ovine Chr 9 is represented by a 15-cM region containing 5 common markers. The significant genomic conservation of marker order will allow use of linkage maps in both species to facilitate the search for quantitative trait loci (QTLs) in cattle and sheep. Received: 20 September 1992 / Accepted: 18 November 1997     

An Autosomal Genetic Linkage Map of the Sheep Genome

We report the first extensive ovine genetic linkage map covering 2070 cM of the sheep genome. The map was generated from the linkage analysis of 246 polymorphic markers, in nine three-generation fullsib pedigrees, which make up the AgResearch International Mapping Flock. We have exploited many markers from cattle so that valuable comparisons between these two ruminant linkage maps can be made. The markers, used in the segregation analyses, comprised 86 anonymous microsatellite markers derived from the sheep genome, 126 anonymous microsatellites from cattle, one from deer, and 33 polymorphic markers of various types associated with known genes. The maximum number of informative meioses within the mapping flock was 222. The average number of informative meioses per marker was 140 (range 18-209). Linkage groups have been assigned to all 26 sheep autosomes.     

Twenty-five loci form a continuous linkage map of markers for human chromosome 7

We have constructed a primary genetic linkage map from DNA markers that define 25 loci on chromosome 7. The markers form a continuous linkage group of 141 cM in males and 340 cM in females; female genetic distances were on average more than twofold higher than those in males throughout the chromosome. The average heterozygosity of the loci was 45%. A subset of the markers can be used for efficient application of this map to studies of human genetic disease.     

Linkage mapping of AFLP markers in a wild population of great reed warblers: importance of heterozygosity and number of genotyped individuals

Amplified fragment length polymorphisms (AFLP) are dominant markers frequently used to build linkage maps where heterozygosity could be inferred by a backcross breeding strategy. In the present study, we describe the utilization of an unmanipulated great reed warbler, Acrocephalus arundinaceus pedigree to infer heterozygous genotypes of AFLP markers in order to map these markers to a partial linkage map previously based on microsatellites. In total, 50 of the 83 autosomal AFLPs (60%) and 4 of 5 Z-linked AFLPs (80%) were mapped. For each marker, on average, 88% of the expected number of heterozygote parents was detected. The likelihood of map assignment was to a large extent due to the number and density of microsatellite markers already in the map. The 'parsimonious linkage map', that is the map based on the most parsimonious location of all significantly linked markers, consisted of 21 autosomal linkage groups with 2 to 15 markers and had a total map size of 552 cM in males and 858 cM in females. The Z-chromosome linkage group with 12 markers had a size of 155 cM. The autosomal 'framework linkage map', that is the map based only on markers with an unambiguous position, had a total size of 237 cM in males and 440 cM in females, respectively. The inclusion of AFLPs enlarged the previous map substantially (e.g. the autosomal parsimonious linkage map became 441 cM and 621 cM larger for male and female recombination, respectively). The probability that an AFLP became mapped increased with increasing level of heterozygosity, whereas the probability of mapping into a framework position increased with both heterozygosity and number of genotyped individuals. Our results suggest that AFLP provides a fast and inexpensive means of enlarging genetic maps already composed of markers with high polymorphism, also in wild populations with unmanipulated pedigrees.     

A mapped set of genetic markers for human chromosome 9

A genetic map of markers for human chromosome 9, spanning a genetic distance of 147 cM in males and 231 cM in females, has been constructed from linkage studies with 19 loci in a large panel of reference families. The markers included four classical systems previously assigned to chromosome 9, and restriction fragment length polymorphisms of two cloned genes, ABL oncogene and argininosuccinase synthetase pseudogene 3 (ASSP3). The remaining 13 marker loci, with an average heterozygosity of 42%, were defined by arbitrary DNA probes newly ascertained from genomic libraries; seven of them were variable number of tandem repeat (VNTR) loci. A subset of 7 of the 19 linked markers is proposed for a primary map that could detect linkage with a genetic defect within the covered region of chromosome 9, provided that at least 45 phase-known meioses were available for study in an affected family.     

Linkage mapping of genes encoding bone morphogenetic proteins 1, 4 and 5 in Sheep

Probes: cDNA clones for bovine BMP1 , BMP4 and BMP5 ¹ were used to develop RFLP markers for use with sheep genomic DNA, in order to map the ovine homologues of these genes on the sheep genetic linkage map.     

A first linkage map of Cichorium intybus L. using a one-way pseudo-testcross and PCR-derived markers

We have used a one-way pseudo-testcross mapping strategy in combination with different types of PCR-based markers (RAPD, AFLP, SAMPL) to construct a first linkage map for variegated chicory (Cichorium intybus L. var. silvestre Biskoff, n=9), a self-incompatible vegetable species. The success of such a strategy depends on the presence of sufficiently high levels of heterozygosity in the individual plant which is being mapped and on the informativeness of the marker system that is used. A total of 371 markers, comprising 16 RAPDs, 72 SAMPLs and 283 AFLPs, were scored in 46 F₁ individuals obtained from an interspecific cross between a C. intybus outbred individual and a C. endivia inbred line. Grouping of the markers at a LOD score of 4.0 resulted in 13 linkage groups covering 1330 cM. A framework map covering 1201.4 cM was assembled by using all markers that could be ordered with a LOD greater than 2.0. We estimate the total genome size of chicory to be ca. 1405 cM, thus considerably smaller than that estimated for lettuce (1950 cM). The usefulness of the different marker systems that were applied is analysed in terms of level of heterozygosity and marker index, i.e. number of different genetic loci that may be simultaneously analysed per experiment. Out of the 371 markers, 50 of them showed segregation distortion which is discussed in terms of the hybrid origin of the variegated chicory.     

A mapped set of DNA markers for human chromosome 17

We have developed and mapped by genetic linkage a primary set of markers for chromosome 17. The map consists of 21 loci derived from 27 probe/enzyme systems, including eight highly informative markers at loci containing a variable number of tandemly repeated DNA sequences (VNTRs). The map is continuous from the telomeric region of the short arm to the telomeric region of the long arm, covering estimated genetic distances of 218 cM in males and 279 cM in females. The average heterozygosity among all 21 loci in the population sample analyzed is 58%; 77% heterozygosity was observed among the eight VNTR markers that were highly informative. This map will make it possible to detect by linkage the location of genetic defects associated with chromosome 17 and will also provide anchor points for a high-resolution map of this chromosome.