影响绵羊羊毛性状的主效基因和QTL

在绵羊中已经发现了许多影响重要经济性状的主效基因,其中包括影响色素沉着、羊毛质量和角蛋白等的主效基因,而角蛋白对羊毛纤维的形态特征有着重要影响 。在羊毛质量和产量性状上,基因图谱研究已经发现了与其变异相联系的染色体区域。现在面临的主要挑战就是建立一种有价值的分子技术方法来提供绵羊的遗传进展。     

影响绵羊多胎性状主效基因的研究进展

对绵羊多胎基因在分子遗传学方面的研究现状及检测方法进行综述.     

羊经济性状主效基因研究进展

与畜禽经济性状相关的主效基因的研究越来越受到关注。本文就与绵、山羊经济性状相关的主效基因研究进展进行综述,为羊主效基因的进一步研究提供参考。     

绵羊繁殖性状相关主效基因的研究进展

繁殖性状是绵羊的主要经济性状之一,一直以来受到国内外研究者的关注,关于提高绵羊繁殖力的研究报道已有很多。近年来,随着分子生物技术的兴起与迅速发展,结合繁殖技术,使得提高绵羊繁殖性能的研究已深入到分子水平,并取得一定成绩。从数量遗传学角度来讲,绵羊繁殖性状遗传力为0.125,属于低遗传力性状,通过传统选择方法获得遗传进展的     

肉牛经济性状主效基因研究进展

牛是重要的家畜之一,在役用、肉用和乳用等方面对社会有着重要的贡献。通过鉴定牛经济性状相关基因及其变异有助于提高育种效率,增加经济效益。随着现代生物技术的发展,对牛经济性状主效基因的挖掘变得更加准确。已鉴定与牛生长发育相关的PLAG1基因,与繁殖相关的GDF9基因,与肉质相关的CAST基因,与胴体相关的MSTN基因,与毛色相关的MC1R基因,与泌乳相关的DGAT1基因等。针对牛不同性状进行合理的分子选育对牛业发展有着重要的经济价值和意义。本文对近年来黄牛生长发育性状、繁殖性状、肉质性状、胴体性状、毛色性状和泌乳性状主效基因研究进展进行综述,为今后黄牛遗传育种研究提供参考依据。     

猪繁殖性状主基因和QTL研究进展

繁殖性状是养猪生产过程中重要的经济性状。如何提高猪的繁殖性状直接影响着养猪业的经济效益。本文综述了猪繁殖性状主基因和QTL,并对影响猪繁殖性状的主基因和QTL研究进展作了阐述。     

猪繁殖性状主基因和QTL研究进展

繁殖性状是养猪生产过程中重要的经济性状。如何提高猪的繁殖性状直接影响着养猪业的经济效益。本文综述了猪繁殖性状主基因和QTL,并对影响猪繁殖性状的主基因和QTL研究进展作了阐述。     

绵羊经济性状相关基因研究进展及其应用

绵羊是重要的农业经济动物之一,不同绵羊品种具有各自独特的性状。利用性状存在变异的绵羊个体,对其进行基因组水平的分析,可以定位获得影响某种性状的基因区段或主效突变位点,鉴定得到的这些重要基因可为绵羊遗传育种提供分子标记,加快遗传选育进程。文章综述了在绵羊中鉴定得到的影响繁殖、生长、抗病及抗逆性状的主效基因发现过程及相应的调控机理,同时还综述了这些基因在绵羊分子育种方面的研究进展,有助于后续探索这些重要基因的具体分子机制,并为绵羊分子育种提供新思路。     

国外部分高繁殖力绵羊主效基因简述

繁殖性状是绵羊的重要经济性状。作者就国外一些高繁殖力绵羊品种的繁殖特性以及相关主效基因的发现、遗传效应、定位等研究进展作一综述。      

猪繁殖力主基因和QTL的研究进展

繁殖是养猪生产过程中的关键一环 ,该环节成功与否直接影响整个养猪业的经济效益。传统数量遗传学在指导家畜育种中起到了重要的作用 ,但是繁殖性状遗传力低、性状表现晚、而且是限性遗传 ,通过常规选择难以有所进展。中国猪 ,尤其是太湖猪 ,以其超高繁殖率闻名于世 ,国内外学者对其高繁殖性能的遗传机制进行了研究 ,提出了窝产仔数主效基因假说 ,并通过候选基因法、基因组扫描法等方法进行了研究 ,期望找到控制产仔数的主基因 ,从而为猪繁殖性状的遗传改良提供了新的途径。目前太湖猪窝产仔数主效基因探索已有成功的报道 ,本文将对猪高繁殖…     

紫花苜蓿QTL与全基因组选择研究进展及其应用

四倍体紫花苜蓿是重要的豆科牧草之一,由于其复杂的遗传背景与二倍体作物相比遗传作图与重要性状数量性状位点(quantitative trait locus,QTL)定位研究相对滞后。然而,二倍体苜蓿的相关研究起步较早,已经建立了高密度遗传图谱和物理图谱,这些研究为四倍体苜蓿遗传作图与QTL定位奠定了基础。随着第三代分子标记与测序技术的快速发展,极大地促进了四倍体苜蓿的高密度遗传图谱构建与QTL定位研究,并借助分子标记辅助育种技术对提高苜蓿选育效率,加速育种进程具有重要意义。本文对苜蓿遗传图谱构建与QTL定位研究及发展趋势进行了总结,并对苜蓿关联作图与全基因组选择的研究进展及应用前景加以概述,旨在为读者就相关研究领域有较全面的了解。     

乌骨绵羊与黑色素的研究进展

黑色素是一类具有光保护、化学保护和体外抗病毒特别是抗艾滋病病毒等作用的生物多聚体,其在医药、保健和化妆品行业都有着非常广阔的应用前景。本文综述了动物黑色素的性质、分类、生成及应用等方面的研究进展;并简要介绍了乌骨绵羊黑色素特性、分布与沉积及黑色素生成相关基因的研究情况。     

影响猪肉质的主效基因RN的研究进展

RN基因是近年来研究较热的影响猪肉品质的一个主效基因 ,它由LeRoy等人于 1 990年正式提出。该基因位于猪 1 5号染色体上 ,包括突变的显性基因RN和正常的隐性基因rn 2个等位基因。目前主要根据猪肉中肌糖原含量来划分RN基因型 ,肌糖原含量较低的为非携带者 ,基因型定为rn/rn,肌糖原含量较高的为携带者 ,基因型定为RN/—。RN基因在汉普夏猪中有较高的频率 ,在其他品种猪中频率极低 ,甚至为 0。RN基因在物理图谱上被定位到猪 1 5q2 1 2 2。RN基因是一个多效应的数量性状座位 ,尽管它的表达产物还不清楚 ,但目前普遍认为它影响猪肉的肌糖原含量、肉质、肉加工后的产出率 ,它对猪的瘦肉量、日增重也有一些影响。获得RN基因的DNA探针和研制RN基因的诊断试剂盒将是RN基因未来研究的一个趋势     

Multiple trait genetic evaluation of ewe traits in Icelandic sheep

The prolificacy of the ewes was measured as the number of lambs born per ewe mated (NLB) when the ewes were 1–4 years of age. The ewe productivity related to the same age interval was measured by special ewe production indices (EPI). The genetic parameters for these traits were estimated by a series of bivariate REML analyses using animal models. The material used for the genetic analysis contained records on 193 213 ewes. The heritability estimates for NLB were h² = 0.17, 0.13, 0.11, 0.10 for the four respective age classes. Corresponding estimates for EPI were h² = 0.16, 0.17, 0.17, 0.15. The genetic correlations among NLB at different ages ranged from 0.63 to 0.98 and among EPI from 0.82 to 0.99. The genetic correlations between NLB and EPI were generally low. The material used for estimating the breeding values by the MT‐BLUP Animal Model consisted of 1.5 million individuals in the pedigree file. In total 815 782 ewes had records for the NLB and 763 491 ewes had production index (at least 1 year). The records were registered in the years 1990–2006. All possible missing patterns were present in the data. In the iteration process expected values for missing traits were generated and solutions were obtained on canonical transformed scale. The genetic evaluations were run independently for NLB and EPI for computational convenience given the correlations between these traits were negligible.     

不同品种绵羊和山羊主要先天性免疫指标的比较

对4个山羊品种和4个绵羊品种的7项主要先天性免疫学指标进行了检测并比较。对动物进行颈静脉采血,制备血清,用ELISA试剂盒测定IL-1、IL-2、IL-6、IL-18、IFN-γ、NK细胞、血清溶菌酶。利用生物统计学的方法和原理,以品种和品种来源地为应变量对检测结果进行比较分析。结果表明,山羊当地品种的NK和LYS高于引进品种（P〈0.05）;绵羊引进品种的IL-1、IL-2、IL-6、IL-18、IFN-γ、NK、LYS均明显高于地方品种（P〈0.01）。在不同品种之间,莱芜黑山羊NK和LYS水平高于崂山奶山羊、波尔山羊和鲁波山羊,萨福克羊的IL-1、IL-6、IL-18、IFN-γ、LYS水平最高且差异极显著（P〈0.01）。小尾寒羊IL-18、IFN-γ水平最低且差异极显著（P〈0.01）。说明不同种群绵羊、山羊的先天性免疫水平存在显著差异,为以后抗病育种提供合理的试验数据。     

牛羊补偿生长的研究进展

综合了当今世界对草食家畜补偿生长的研究,探讨了影响补偿生长的主要因素是年龄、基因类型、营养限制的程度和持续时间、补充营养物质的质量和持续时间.补偿生长的作用机制是通过营养限制减少维持需要、增加采食量、增加生长效率和增加消化道内容物来实现的,特别在目前有关补偿生长的研究中,激素是热点话题,不同激素的作用可以看作是补偿反应的一个完整组成部分.     

Functional investigation of a QTL affecting resistance to Haemonchus contortus in sheep

This study reports a functional characterization of a limited segment (QTL) of sheep chromosome 12 associated with resistance to the abomasal nematode Haemonchus contortus. The first objective was to validate the identified QTL through the comparison of genetically susceptible (N) and resistant (R) sheep produced from Martinik × Romane back-cross sheep. The R and N genotype groups were then experimentally infected with 10 000 H. contortus larvae and measured for FEC (every three days from 18 to 30 days post-challenge), haematocrit, worm burden and fertility. Significant differences in FEC and haematocrit drop were found between R and N sheep. In addition, the female worms recovered from R sheep were less fecund. The second step of the characterization was to investigate functional mechanisms associated with the QTL, thanks to a gene expression analysis performed on the abomasal mucosa and the abomasal lymph node. The gene expression level of a candidate gene lying within the QTL region (PAPP-A2) was measured. In addition, putative interactions between the chromosome segment under study and the top ten differentially expressed genes between resistant MBB and susceptible RMN sheep highlighted in a previous microarray experiment were investigated. We found an induction of Th-2 related cytokine genes expression in the abomasal mucosa of R sheep. Down-regulation of the PAPP-A2 gene expression was observed between naïve and challenged sheep although no differential expression was recorded between challenged R and N sheep. The genotyping of this limited region should contribute to the ability to predict the intrinsic resistance level of sheep.     

Genetic structure and diversity among sheep breeds in the United States: identification of the major gene pools

Understanding existing levels of genetic diversity of sheep breeds facilitates in situ and ex situ conservation activities. A comprehensive evaluation of US sheep breeds has not been previously performed; therefore, we evaluated the genetic diversity among and within 28 US sheep breeds. Both major and minor breeds were included in the analysis and consisted of 666 animals from 222 producers located in 38 states. The level of within-breed genetic diversity was variable and not dependent upon status of a breed as a major or minor breed. Bayesian cluster analysis indicated the breeds were grouped more by physiological differences (meat vs. wool production) rather than geographic origin. Results suggest several actionable items to improve in situ and ex situ conservation. The results clearly identify breeds in need of increased in situ and ex situ management (e.g., Hog Island and Karakul) and allow several suggestions for in situ management of flocks. Conversely, several of the breeds appear genetically similar and therefore require less emphasis on collecting germplasm samples for the gene bank. Commercially important breeds (e.g., Rambouillet and Suffolk) were found to have substantial variation, which should enable breeders to proceed, unencumbered by genetic diversity concerns, with selection strategies that maximize profit.     

影响羊毛性状和羊毛品质的主要基因和QTL的研究进展

羊毛细度、羊毛长度、羊毛强度以及弯曲度等性状都是影响羊毛品质的重要经济性状.用传统的技术改良这些性状需要较长的时间和费用,特别是对遗传力低的性状进行选择,很难精确估计此类数量性状座位的基因效应.