扁穗牛鞭草种质遗传多样性的ISSR分析

用ISSR标记对来自中国西南地区(四川、重庆、贵州)的28份扁穗牛鞭草材料的遗传多样性进行了检测。从96个ISSR引物中共筛选出13个多态性明显、反应稳定的引物。28份材料的DNA共扩增出129条谱带,平均每个引物扩增出9.9条带,多态性条带比率达84.2%。材料间遗传相似系数为0.466~0.980,表现出丰富的遗传多样性。通过聚类分析和主成分分析,将28份扁穗牛鞭草分为两大类,同一地区的扁穗牛鞭草品种(系)基本聚在同一类,呈现出一定的地域性分布规律。     

利用EST-SSR标记分析西南扁穗牛鞭草种质的遗传多样性

利用禾谷作物EST-SSR标记对采自我国西南地区的40份野生扁穗牛鞭草和3份扁穗牛鞭草国审品种的遗传变异和亲缘关系进行了研究。试验筛选出23对引物对43份供试材料进行扩增,共获得323条带,其中多态性条带261条,多态性条带比率(PPB)达80.4%,多态信息含量(PIC)为0.354~0.500,平均值为0.474,遗传相似系数(GS)为0.690~0.913,表现出丰富的遗传多样性。聚类分析结果表明,各供试材料间的聚类与其地理来源及形态特征具有一定的相关性。5 个扁穗牛鞭草地理类群间的分子方差分析(AMOVA)揭示了供试的扁穗牛鞭草类群内的遗传变异占总变异的95.32%,类群间变异占总变异的4.68%。表明禾谷作物的EST-SSR能用于扁穗牛鞭草遗传多样性研究,是一种有效的分子标记。本研究结果为扁穗牛鞭草种质的收集、利用及育种提供了理论依据。     

鸭茅EST-SSR标记在4种禾草上的可转移性

为了检验鸭茅EST-SSR标记在几种禾本科植物上的可转移性并筛选出可应用于后续研究的引物,本研究用40对可在鸭茅(Dactylis glomerata)上扩增产物的鸭茅EST-SSR引物,分析了6份多花黑麦草(Lolium multiflorum)、6份高羊茅(Festuca arundinacea)、3份扁穗牛鞭草(Hemarthria compressa)和3份牛鞭草(H.altissima)共18份材料的转移率、遗传多样性和亲缘关系。结果表明,多年生黑麦草和高羊茅可转移率为60%,扁穗牛鞭草和牛鞭草转移率最低,均为50%,26对引物共获得条带128条,多态性条带121条,多态性比(PPB)为94.53%,平均扩增出多态性条带4.92条,平均多态性信息量0.952。18份材料遗传相似系数范围为0.208~0.974,在遗传系数为0.68时,4个物种分别独自聚为一大类。本研究证实利用鸭茅EST序列开发的EST-SSR在有一定亲缘关系的物种间转移是可行的,可转移的引物对未来禾本科遗传育种研究有一定的参考价值。     

野牛草种质基于SRAP标记的遗传多样性研究

野牛草(Buchloe dactyloides)是一种低养护的暖季型草坪草,本研究利用相关序列扩增多态性（SRAP）标记对来自美国、加拿大和日本的31份野牛草材料进行遗传多样性分析。结果表明,用19对引物组合共扩增出271条多态性条带,多态性位点百分率为86.86%,材料间的遗传相似系数(GS)为0.586 5~0.916 7,平均GS值为0.669 1。两个材料在不同的引物组合扩增下,分别出现特异性条带和缺失性条带,这些条带可用于野牛草基因型的鉴定。非加权成对算术平均法（UPGMA）聚类分析和主成分分析结果表明,供试材料可聚成两类,而相同地理来源的材料并未聚为一类。     

川西北高原野生垂穗披碱草RAPD变异研究

采用随机扩增多态性标记(Random Amplified Polymorphic DNA,RAPD)对来自川西北高原的28份垂穗披碱草遗传多样性和遗传关系进行了分析。结果表明:试验选用13条引物共扩增出150条条带,其中多态性条带107条,多态性条带比率为71.3%,每个引物扩增的多态条带数为8.23条,遗传相似系数(GS值)为0.703～0.982,平均值为0.851,表明了川西北高原的野生垂穗披碱草材料具有丰富的遗传多样性。聚类分析和主成分分析结果都表明大部分来自相同或相似生态地理环境的材料能聚在一起,具有较近的亲缘关系,表明供试材料的聚类和其生态地理环境间有一定的相关性,与其他的研究结论具有一定的相似性。最后,本研究还探讨了川西北地区野生垂穗披碱草资源的保护及其利用。     

应用RAMP标记分析长白山地区中国林蛙的遗传多样性

应用随机扩增徽卫星多态性DNA（RAMP）标记技术对长白山地区中国林蛙60个个体间遗传多样性进行了分析。以便为中国林蛙种质资源的保护和利用以及物种分化研究提供基础资料。结果表明：120个RAMP引物中。有14个引物组合可扩增出清晰且具多态性的条带。这14个引物组合共扩增出107条带,其中105条具有多态性,多态条带比率为98．13％。每个引物可扩增出3～10条多态性条带,平均7．5条。多态条带比率、Shannon多样性指数（I）以及Nei氏基因多样度（h）均显示长白山地区中国林蛙具有较为丰富的遗传多样性。RAMP标记遗传相似性系数（岱）变异范围为0．4860～0．8505,平均值为0．6634,以GS平均值0．6634为闻值,可将所有供试材料划分为10类,其中大部分个体归为同一类,群体内并没有形成较明显的遗传分化。     

扁穗冰草不同地理种群cpDNAtrnT-trnL多态性分析

对91份不同产地扁穗冰草(Agropyron cristatum(L.)Gaertn)样品的遗传多样性和遗传结构进行研究。采用叶绿体cpDNAtrnT-trnL直接测序的方法和邻接法(NJ)对91份扁穗冰草样品进行遗传多样性和遗传结构分析。结果显示:物种水平上单倍型多样性(Hd)指数为0.608,核苷酸多样性(Pi)指数为0.00295;种群水平上Hd介于0~0.9722,Pi指数介于0~0.00749。分子方差分析表明,扁穗冰草大部分遗传变异(91.63%)发生在居群内,居群间的基因流(Nm=5.474)较高,群体内变异是扁穗冰草的主要变异来源;NJ树表明,受试的6个野生种群可分为4大类群。扁穗冰草的遗传多样性居群内遗传分化较大。     

49份野生扁蓿豆种质资源的AFLP遗传多样性分析

应用AFLP标记对采自中国7个省市自治区的49份野生扁蓿豆种质材料进行遗传多样性及遗传结构的分析。研究结果显示:(1)利用4对条带清楚且稳定的AFLP引物组合共扩增出298个条带,其中多态性条带有219个,多态性条带比率为73.5%,每个引物扩增多态性条带数平均为54.8条。(2)49份野生扁蓿豆种质间多态性比率平均为32.70%,Nei’s基因多样性指数平均为0.115,Shannon多样性指数平均为0.172,表明供试种质材料间遗传多样性较丰富,遗传多样性水平较高。(3)河北省的扁蓿豆种质遗传变异最丰富,辽宁省的扁蓿豆种质变异幅度最小,不同地理类群间的扁蓿豆种质遗传多样性指数有显著差异。(4)种质材料间基因分化系数为0.6436,说明64.36%的遗传变异来源于不同种质材料间;地区间基因分化系数为0.2895,说明28.95%的遗传变异来源于不同地区间。表明地区间差异小于种质材料间的遗传变异。(5)UPGMA方法的聚类分析和主成分分析结果表明,49份种质材料间的遗传相似系数(GS)为0.5849~0.9904,遗传距离(GD)为0.0096~0.5363,49份扁蓿豆种质分为6大类,表现出明显的地域性。     

基于SCoT标记的饲用燕麦品种遗传结构及指纹图谱分析

采用目标起始密码子多态性标记（SCoT）对目前国内种植利用的36个饲用燕麦品种进行了遗传变异结构及指纹图谱分析。结果显示,从80个SCoT引物中筛选出多态性较好、条带清晰且重复性高的引物15个,共扩增出146条条带,不同引物扩增出的多态性条带数为3~9条,平均为6.4条,多态性比率为65.75%,平均有效等位基因数（Ne）为1.46,平均Nei’s基因多样性指数为0.27,平均Shannon’s多样性指数为0.38。基于4个多态性较高的核心引物组扩增的14个位点,构建了36个燕麦品种的DNA指纹图谱,其能够将供试燕麦品种区分并准确鉴定。供试品种的DICE遗传相似性系数为0.7596~0.9507,平均值为0.8473;基于遗传相似系数的非加权组平均法（UPGMA）聚类分析结果显示,可将36个品种分为四大类,聚类与其来源的关联性不高。群体遗传结构分析表明,国外引进品种遗传组成分布均匀,有32.1%的品种具有混合来源,而国内品种分布相对集中且仅有25.0%的品种有混合来源,表明供试的国内种植利用的燕麦品种遗传基础较狭窄,来源相对单一。结果为燕麦品种的鉴定、新品种的选育等提供了理论参考。     

地毯草种质资源ISSR标记遗传多样性分析

地毯草(Axonopus compressus)是华南地区使用的多年生草本植物,本研究通过ISSR标记对华南地区64份地毯草种质资源的遗传多样性和亲缘关系进行分析。结果表明,25对ISSR引物共扩增出208条清晰谱带,大小在300~1 500bp,其中多态性条带有196条,多态性比率为94.23%,25对引物扩增条带数在4~15条,平均每对引物8.32条,遗传相似系数是0.46~0.99。通过UPGMA方法对64份地毯草材料进行聚类分析。结果表明,来自相同采集地区的材料并没有完全聚在一类,供试材料间出现较大的遗传差异。本研究结果可为今后开展地毯草种质资源遗传保护、品种鉴定、新品种选育提供基础。     

江西地方猪种血液蛋白及酶的多态性研究

采用聚丙烯酰胺凝胶和淀粉凝胶电泳方法测定了１４个江西地方猪种的血清转铁蛋白（Ｔｆ）、前白蛋白（Ｐａ）、后白蛋白（Ｐｏ）、淀粉酶（Ａｍ）、血液结合素（Ｈｐｘ）和铜蓝蛋白（Ｃｐ）的多态性，统计和计算了基因频率、标准遗传距离，并进行了聚类分析。结果表明，江西地方猪种在Ｔｆ、Ｐａ、Ｐｏ、Ａｍ、Ｈｐｘ位点存在高度的多态性，各品种间的标准遗传距离从０．００５５～０．２２５１不等，显示江西地方猪种存在明显的遗传多样性。     

中国牦牛的遗传多样性

本文作者详细论述了中国牦牛的遗传多样性。中国牦牛在世界上数量和类群（或类型）最多，可分为高原型和横断高山型。主要分布在以青藏高原为中心地带及其东部边缘的青海、基本和四川的西部。它是当地人民基本的生活来源和重要的经济支柱，通过细胞水平、生化水平、分子水平等的研究结果表明，中国牦咎各地方类群间存在一定的差异，但遗传变异程度较小，遗传多样性贫乏，这些结果对于中国牦牛的保种、选育、开发利用都具有重要的指导意义。     

DNA Testing in Neurologic Diseases

DNA testing is available for a growing number of hereditary diseases in neurology and other specialties. In addition to guiding breeding decisions, DNA tests are important tools in the diagnosis of diseases, particularly in conditions for which clinical signs are relatively nonspecific. DNA testing also can provide valuable insight into the risk of hereditary disease when decisions about treating comorbidities are being made. Advances in technology and bioinformatics will make broad screening for potential disease‐causing mutations available soon. As DNA tests come into more common use, it is critical that clinicians understand the proper application and interpretation of these test results.     

The role of genetic engineering in livestock production

In this paper we discuss the use of genetic engineering in livestock production. We examine the main two different aspects of genetic engineering: cloning and transgenesis. After commenting what has been expected from both techniques in livestock production in the last 25 years, the practical difficulties for implementing cloning and transgenesis are examined. Apart from technical difficulties, problems derived from the detection of genetically superior animals and evaluation of the clones and the transgenic animals make these techniques less interesting than they appear to be. Most of the observed variability of the economically interesting traits is not genetic, genetic evaluation needs a large number of animals and cloning success will represent a serious loss of genetic variability and the loss of the flexibility needed for markets in constant evolution. There is a risk in transgenic animals of production of new intermediate biochemical products that may be toxic, allergenic or carcinogenic. The benefits produced by transgenic animals hitherto hardly justify this risk. The expectations that genetic engineering produced 25 years ago should be re-examined, considering the risks and the high investment required.     

Analysis of Two Chinese Yak(Bos grunniens) Population Using Bovine Microsatellite Primers

Two Chinese domestic yak populations representing the Plateau type and the Huanhu Alpine type were analysed with 12 bovine microsatellite primers. All primer pairs functioned in the yak genome and polymorphism was found at all loci. The allele size ranges and frequencies of the two yak populations were similar and there was considerable overlap with the allele size ranges observed in cattle. Data for European cattle breeds was obtained from the Cattle Diversity Database(CaDBase)to interpret the heterozygosity and genetic distance estimates in yak populations. Heterozygosity estimated for the two yak populations was comparable to that of European cattle while Nei's Genetic Distance DA between the two yak populations was less than distances between the most closely related German cattle breeds. Bovine microsatellite primers proved to be a valuable tool for characterization of yak populations.     

Influence of foreign stallions on the Swedish Warmblood breed and its genetic evaluation

The objective of this study was threefold: 1) To survey the use and impact of foreign stallions in the Swedish Warmblood (SWB) breed 2) To investigate the impact of including genetic groups in the genetic evaluation of the SWB and 3) To estimate the impact of incomplete pedigree information on the estimated breeding values (EBVs) for stallions. Data consisted of 189,330 horses of which 50,907 had performance information. Studbook of origin was determined for stallions with at least 5 progeny tested in Sweden. Those 757 stallions had together 116,505 progeny registered in the SWB. Genetic groups were formed according to preliminary analyses of the genetic levels in dressage and show jumping of the different populations. During the first studied period, comprising horses born before 1980, about 80% of the foals were sired by Swedish born stallions, whereas these only sired 40% of the horses born 1990–2003. In this period Holstein stallions had sired 21% of the foals and Dutch stallions (KWPN) 10%. The proportion of mares covered by foreign stallions increased after the early 1980s to about 80% in 2006. Some of the foreign populations, e.g., Holstein, Selle Francais and KWPN, have significantly affected the show jumping performance level of the SWB breed in the past although the deviation from SWB stallions has become smaller over time. Regarding dressage, no particular foreign population has consistently shown such an impact on the performance although Oldenburg stallions seem to be influential lately. The pedigree completeness (PEC values) of the horses included amounted on average to 0.845 for horses with performance data and to 0.907 for stallions with at least 15 progeny. Foreign stallions had an average PEC value of 0.858. When simulating no pedigree information available for foreign stallions, the EBVs of these stallions changed on average by 19–22 index units, which equals about one genetic standard deviation. Thus, keeping complete and correct pedigree registers is crucial for the assessment of reliable EBVs of SWB horses. Including genetic groups in the genetic evaluation of the SWB resulted in hardly any re-ranking of horses. Correlations between EBVs were about 0.99. Inclusion of genetic groups caused larger standard errors of the EBVs. Furthermore, as the pedigrees on average have great depth, and partially also because Warmblood sport horses have become a mix of many different populations, it was not recommended to include genetic groups in the model for future routine genetic evaluations of SWB.     

毛乌素不同类型沙地油蒿种群遗传分化的ISSR分析

利用12对微卫星引物对毛乌素沙地油蒿种群的遗传分化、基因流进行分析,采用Nei’s指数和Shannon指数估算3个不同类型沙地种群的遗传多样性,计算种群相似系数和遗传距离,利用遗传距离构建系统树。结果表明:(1)种群遗传多样性分析显示,油蒿种群多态位点百分率为100%,说明油蒿种群基因组ISSR具有较高的多样性。(2)在遗传距离为6.0处可将184个样株大致分为三类,涵盖了135个样株,占采样总量的73.34%。结合样地定位记录,聚类结果与样株空间分布具有一致性,即可分为流动沙地、固定沙地、半固定沙地油蒿种群。(3)流动沙地与固定、半固定沙地油蒿种群间的基因流较小,分别为0.7929和0.6848,半固定与固定沙地油蒿种群间存在着较高的基因流,为6.2930。半固定与固定沙地种群间的遗传一致度较高,为93.77%;流动沙地种群Shannon指数低。     

A review of genetic parameter estimates for wool, growth, meat and reproduction traits in sheep

Genetic parameters for a range of sheep production traits have been reviewed from estimates published over the last decade. Weighted means and standard errors of estimates of direct and maternal heritability, common environmental effects and the correlation between direct and maternal effects are presented for various growth, carcass and meat, wool, reproduction, disease resistance and feed intake traits. Weighted means and confidence intervals for the genetic and phenotypic correlations between these traits are also presented. A random effects model that incorporated between and within study variance components was used to obtain the weighted means and variances. The weighted mean heritability estimates for the major wool traits (clean fleece weight, fibre diameter and staple length) and all the growth traits were based on more than 20 independent estimates, with the other wool traits based on more than 10 independent estimates. The mean heritability estimates for the carcass and meat traits were based on very few estimates except for fat (27) and muscle depth (11) in live animals. There were more than 10 independent estimates of heritability for most reproduction traits and for worm resistance, but few estimates for other sheep disease traits or feed intake. The mean genetic and phenotypic correlations were based on considerably smaller numbers of independent estimates. There were a reasonable number of estimates of genetic correlations among most of the wool and growth traits, although there were few estimates for the wool quality traits and among the reproduction traits. Estimates of genetic correlations between the groups of different production traits were very sparse. The mean genetic correlations generally had wide confidence intervals reflecting the large variation between estimates and relatively small data sets (number of sires) used. More accurate estimates of genetic parameters and in particular correlations between economically important traits are required for accurate genetic evaluation and development of breeding objectives.     

基于SSR分子标记的药用黄芪遗传多样性与遗传结构分析

为了能更好的了解药用黄芪（Astragali Radix）遗传多样性及遗传结构,本试验利用10对SSR引物对来自17个产地共380个样本的蒙古黄芪、膜荚黄芪进行遗传多样性及结构分析,结果显示药用黄芪具有较高程度的遗传多样性水平（I=2.112,H=0.781）,其中蒙古黄芪遗传多样性水平（I=2.241,H=0.804）要高于膜荚黄芪（I=1.982,H=0.757）,且两种黄芪的遗传变异主要发生在居群内;UPGMA聚类分析及STRUCTURE居群遗传结构分析可将其分为3组,即膜荚黄芪为单独一组,蒙古黄芪分为两组,其中来自山西产区的大部分居群分为一组,来自内蒙产区及部分山西产区的居群分为另一组。本研究结果对药用黄芪种质资源的有效利用、遗传多样性的保护、育种及开发优质黄芪种质资源提供一定的理论基础。     

Population dynamics of inherited copper toxicosis in Dutch Bedlington terriers (1977-1997)

Inherited copper toxicosis in Bedlington terriers was 1st reported in 1975 and the entire Dutch population was examined from 1976 until the present for presence of the disease. To examine the effect on the prevalence of the disease of excluding affected dogs from breeding we have compared 2 time cohorts, the 1st consisting of dogs born from January 1, 1976, to January 1, 1986 (n = 155), and the 2nd of dogs born from January 1, 1990, to January 1, 1997 (n = 195). The diagnosis was made in the 1st cohort by evaluating liver biopsies, and in the 2nd cohort with a DNA marker. The population was also resolved into clusters of related dogs to analyze the familial distribution of the disease in the population and to search for ancient founders of the disease among the ancestors of sick dogs. Forty-six percent of dogs examined between 1976 and 1986 had copper toxicosis. Eleven percent of dogs examined in the 2nd cohort had evidence of disease. This reduction was achieved while maintaining the already limited genetic heterogeneity of the population: the number of clusters and the mean relatedness between the clusters were similar in both time cohorts. The disease was evenly distributed over the clusters of related dogs in both cohorts. All ancestors had contributed to the distribution of copper toxicosis and no specific founders could be identified. This indicates that when the breed was established in The Netherlands, the disease was already highly prevalent in the founding dogs.