全基因组关联分析(GWAS)在鸡重要经济性状基因定位中的研究进展

全基因组关联分析（GWAS）是通过分析表型性状和基因遗传变异之间的关联性从而确定影响表型性状的遗传因素的一种方法,目前已广泛应用于畜禽生产中。文章主要对GWAS在鸡生长性状、繁殖性状、蛋品质性状和屠宰性状等重要经济性状基因定位中的研究进展进行综述,旨在为鸡遗传育种和种质改良以及地方特色鸡品种的保种提供思路。     

全基因组关联分析在猪育种中的研究进展

全基因组关联分析(genome-wide association studies, GWAS)是一种利用大规模群体的DNA样本进行全基因组高密度基因型分型，探究与目标性状相关联的遗传变异的研究方法。GWAS在揭示猪重要经济性状的变异规律和推动基因组选择在猪育种中的实际应用等方面有着重要作用。本综述主要围绕GWAS的基本原理、GWAS的分析方法、GWAS在猪育种方面取得研究进展和其未来展望进行综述，以期为利用GWAS进行猪重要经济性状遗传基础的研究提供参考。     

鸡重要性状全基因组关联分析研究现状及展望

全基因组关联研究(GWAS)是在全基因组范围内寻找与动植物重要经济性状相关联的遗传变异,最先应用于人类复杂疾病的研究,随着鸡全基因组图谱的完成与公布,以及不同密度SNP芯片的开发与推广,GWAS已经应用于鸡复杂性状的重要基因检测,是解析重要性状分子遗传机制强有力的分析方法。文章介绍了GWAS研究背景、原理与方法等,综述了GWAS在鸡体重、体尺、屠宰、肉质、繁殖、行为、抗病等重要性状上的研究现状,并预测GWAS技术在未来鸡育种中的应用前景,旨在为进一步利用GWAS进行鸡复杂性状的遗传基础研究以及鸡的全基因组选择(GS)育种提供参考。     

猪肉质性状全基因组关联分析的研究进展

全基因组关联分析(genome-wide association study, GWAS)是在全基因组范围内,以单核苷酸多态性标记(single nucleotide polymorphism sign, SNPs)作为分子遗传标记,筛选出与数量性状相关的SNP、数量性状基因座(quantitative trait locus, QTL)和候选基因的有效手段。猪肉品质是猪的重要经济性状,与人们的肉食营养、肉食品加工和养猪业经济效益密切相关。本文主要对GWAS在猪肉质性状的研究应用展开论述,以期为通过GWAS鉴别影响猪肉质性状的主效基因来改善猪肉品质提供理论依据。     

利用GWAS研究母猪繁殖性状的进展

母猪繁殖性状一直是猪的重要性状之一,母猪繁殖性能的高低关乎着养猪场的规模和养猪业的发展。目前利用GWAS(全基因组关联分析)发现影响母猪产仔数、初生重、断奶重和乳头数等繁殖性状的SNP(单核苷酸多态性)位点,进而发现关联的基因已经成为研究热点之一,并且利用GWAS研究母猪的繁殖性状取得了一定的进展。因此,文章主要对利用GWAS研究母猪繁殖性状的进展进行概述。     

畜禽生长发育相关性状的全基因组关联分析研究进展

全基因组关联分析(GWAS)是近年兴起的用于分析复杂性状的重要研究方法。高通量测序技术的成熟发展使得基于全基因组测序技术和基因芯片技术的GWAS解析畜禽复杂性状成为可能,GWAS的运用对畜禽经济性状相关的SNP、QTL和候选功能基因研究起到关键作用。本文主要对GWAS的基本原理和方法、优劣势以及GWAS在畜禽生长发育相关性状中的应用现状进行综述,并对GWAS在今后畜禽育种中的应用前景进行展望,以期为GWAS在畜禽育种中的深入研究提供参考。     

全基因组关联分析(GWAS)技术在家犬中的应用研究进展

一、全基因组关联分析(GWAS)是目前深度发掘自然群体物种复杂性状相关功能基因的高效手段 全基因组关联分析(GWAS)是最早研究复杂性状和疾病遗传变异的有效方法,其核心是研究分子变异和目标表型性状之间的关联.尤其是近几年来随着高通量测序和高分辨的代谢检测技术的不断发展,以及多种生物信息学技术和统计学方法发展,这些为复杂...     

畜禽数量性状全基因组关联分析统计模型和试验设计的研究进展

数量性状或复杂性状受多种基因和环境因素的控制。这些性状的标记基因和遗传变异是畜禽遗传学研究的一个非常重要的领域。由于全基因组和高密度的SNP芯片对大多数畜禽都可用,全基因组关联研究(GWASs)已经成为畜禽数量性状形成机制研究的首选方法,而GWASs研究的统计模型和实验设计是GWAS分析结果准确的前提。文章简要对畜禽数量性状全基因组关联分析统计模型和实验设计的研究进展进行综述。     

全基因组关联分析在水禽主要数量性状基因座定位的应用现状

水禽的经济性状多为数量性状,数量性状基因座(quantitative trait loci, QTL)是调控数量性状表达的遗传基础,因此QTL的定位是分子育种的基础。全基因组关联分析(genome wide association studies, GWAS)作为鉴定表型与基因型关系的一种分析策略,是挖掘畜禽QTL的重要手段,并已经成功应用于猪、牛、鸡等畜禽的遗传育种工作中。利用GWAS可以定位与水禽经济性状相关的QTL,确定影响水禽性状的功能基因或主效基因,从而实现对水禽重要性状的改良。文章综述了GWAS在水禽重要性状研究上的应用效果,并分析了不足之处,以期为完善水禽遗传育种与遗传改良方法提供参考。     

全基因组关联分析在鸭育种中的研究进展

全基因组关联分析(genome-wide association study, GWAS)是一种在人类或动植物全基因组中寻找变异序列，并筛选与目的性状相关位点的方法。目前，GWAS在畜禽重要经济性状研究中广泛应用。文章叙述了GWAS的基本原理，归纳了GWAS的研究方法和优缺点，并且列举了通过GWAS已定位到的鸭重要经济性状相关的标记位点和候选基因，旨在为后续鸭育种研究提供理论基础。     

Heritability and genetic correlation estimates of semen production traits with litter traits and pork production traits in purebred Duroc pigs

We estimated heritabilities of semen production traits and their genetic correlations with litter traits and pork production traits in purebred Duroc pigs. Semen production traits were semen volume, sperm concentration, proportion of morphologically normal sperms, total number of sperm, and total number of morphologically normal sperm. Litter traits at farrowing were total number born, number born alive, number stillborn, total litter weight at birth, mean litter weight at birth, and piglet survival rate at birth. Litter traits at weaning were litter size at weaning, total litter weight at weaning, mean litter weight at weaning, and piglet survival rate from birth to weaning. Pork production traits were average daily gain, backfat thickness, and loin muscle area. We analyzed 45,913 semen collection records of 896 boars, 6,950 farrowing performance records of 1,400 sows, 2,237 weaning performance records of 586 sows, and individual growth performance records of 9,550 animals measured at approximately 5 mo of age. Heritabilities were estimated using a single-trait animal model. Genetic correlations were estimated using a 2-trait animal model. Estimated heritabilities of semen production traits ranged from 0.20 for sperm concentration to 0.29 for semen volume and were equal to or higher than those of litter traits, ranging from 0.06 for number stillborn and piglet survival rate at birth to 0.25 for mean litter weight at birth, but lower than those of pork production traits, ranging from 0.50 for average daily gain to 0.63 for backfat thickness. In many cases, the absolute values of estimated genetic correlations between semen production traits and other traits were smaller than 0.3. These estimated genetic parameters provide useful information for establishing a comprehensive pig breeding scheme.     

Genetic correlations between competition traits and traits scored at breeding field-tests in Icelandic horses

Relationships between breeding field-test traits and competition traits were studied to investigate whether the latter could be usefully included in the genetic evaluation of Icelandic horses. The current method of genetic evaluation is based on records from breeding field-tests only. The breeding field-test data included 16 401 individual records of Icelandic horses evaluated in 11 countries during 1990–2005. Competition results included 18 982 records of 3790 horses competing in sport and gæðinga competitions in Iceland and Sweden during 1998–2004. In the breeding field-tests, eight conformation traits and eight riding ability traits were scored; height of withers was also recorded. These traits were analysed together with the competition traits tölt(comp), 4-gait, 5-gait and pace test, in bivariate analyses. Animal models were used; the fixed effects for breeding field-test traits included sex by age interaction and country by year interaction. For the competition traits the model included fixed effects of sex, age and event, and a random permanent environmental effect. Estimated heritabilities and genetic correlations for breeding field-test traits were consistent with earlier results; heritabilities ranged from 0.20 to 0.67, and moderate to high genetic correlations were estimated between many of the riding ability traits, and between riding ability traits and some conformation traits. The estimated heritabilities for competition traits were about 0.20, and genetic correlations between competition traits varied from − 0.12 to 1.00. In general, high genetic correlations were estimated between breeding field-test riding ability traits and competition traits. Moderately positive genetic correlations were found between some breeding field-test conformation traits and competition traits. Competition traits add information relating to the breeding goal of the Icelandic horse; they should therefore be added to genetic evaluation in future.     

Genetic parameters and trends for production traits and their relationship with litter traits in Landrace and Yorkshire pigs

Genetic parameters and trends in the average daily gain (ADG), backfat thickness (BF), loin muscle area (LMA), lean percentage (LP), and age at 90 kg (D90) were estimated for populations of Landrace and Yorkshire pigs. Additionally, the correlations between these production traits and litter traits were estimated. Litter traits included total born (TB) and number born alive (NBA). The data used for this study were obtained from eight farms during 1999 to 2016. Analyses were carried out with a multivariate animal model to estimate genetic parameters for production traits while bivariate analyses were performed to estimate the correlations between production and litter traits. The heritability estimates were 0.52 and 0.43 for ADG; 0.54 and 0.45 for BF; 0.25 and 0.26 for LMA; 0.54 and 0.48 for LP; and 0.56 and 0.46 for D90 in the Landrace and Yorkshire breeds, respectively. The ADG and D90 showed low genetic correlation with BF and LP. The LMA had ?0.40, ?0.32, 0.49, and 0.39 genetic correlations with ADG, BF, LP, and D90, respectively. Genetic correlations between production and litter traits were generally low, except for the correlations between LMA and TB (?0.23) in Landrace and ADG and TB (?0.16), ADG and NBA (?0.18), D90 and TB (0.19), and D90 and NBA (0.20) in Yorkshire. Genetic trends in production traits were all favorable except for LMA.     

新扬州鸡公鸡体型结构和精液品质的测定分析

测定了32只40周龄新扬州鸡公鸡体型结构和精液品质,结果表明公鸡体重、体斜长、胸宽、胸围和胸骨长等5个性状间呈显著正相关（P＜0．05）,精液量与有效精子数之间呈显著正相关（P＜0．01）。公鸡体型结构和精液品质间的通径分析表明,胸围和胫长是决定精液浓度的重要因子,其中胸围对精液的直接效应为0．46,胫长对精液浓度的效应为－0．54。     

Genetic analysis of six production traits in Peruvian alpacas

In this study a total of 6499 records were obtained for fibre diameter (FD) and coefficient of variation of FD (CV), 3283 records for greasy fleece weight (GFW), staple length (SL) and shearing interval (SI) and 1802 records of textile value index (TV) obtained from an experimental herd of alpacas exploited in the Peruvian Altiplano.The estimated heritabilities were: 0.412 ± 0.015 (FD), 0.321 ± 0.013 (CV), 0.098 ± 0.016 (GFW), 0.070 ± 0.011 (SL), 0.061 ± 0.012 (SI) and 0.163 ± 0.017 (TV). No significant genetic correlation was found for the pairs FD-CV and CV-GFW whilst the pairs FD-GFW, FD-SI and FD-TV had significant genetic correlations of, respectively, 0.405 ± 0.081, − 0.395 ± 0.078 and − 0.746 ± 0.049. No significant correlations were found for SL except for the pair SL-SI (0.397 ± 0.099). The TV index also showed significant genetic correlations with CV of 0.125 ± 0.061 and with GFW of 0.490 ± 0.070. All estimates of permanent environmental effects (c²) associated with the six analysed traits were statistically significant ranging from 0.008 for SI to 0.259 for CV. Total repeatability for the analysed traits was low for SI (0.069) and SL (0.090), moderate for TV (0.299) and GFW (0.316) and high for FD (0.578) and CV (0.579). The permanent environmental effect associated with CV is significantly correlated with those of the other traits except for FD. The permanent environmental effects associated with GFW and SL seemed to be basically the same (estimated correlation of 0.916 ± 0.062). The permanent environmental effect for TV is highly correlated with those associated with GFW (0.498 ± 0.058) and SL (0.750 ± 0.137). Expected selection response for TV was higher when FD was considered as selection goal instead of TV itself.It would, therefore, be more efficient to use FD rather than empirical indices as selection criterion to increase textile value in Peruvian alpacas. The reported genetic parameters and correlation matrices can be useful to implement multitrait breeding value estimations for alpaca selection.     

Genomewide association study of immune traits in chicken F2 resource population

Immune traits play pivotal roles in animal immune capacity development and disease resistance. Single nucleotide polymorphisms (SNPs) are common forms of genetic variations among individuals, which are thought to account for the majority of inherited phenotypic variations. In this study, we performed genomewide association, using the Illumina 60K SNP BeadChip studies to detect molecular markers and candidate genes associated with immune traits in an F2 population. Sixteen immune traits were measured. We identified 85 significant SNPs (p < 2.98 × 10^?6) with 5% as the genomewide significance threshold, 380 SNPs of suggestive significance (p < 5.96 × 10^?5) from simple model (general linear model, GLM) and 15 SNPs of suggestive significance (p < 5.96 × 10^?5) from the compressed mixed linear model (MLM), which were also found in GLM (six significant SNPs and seven suggestive SNPs). Three significant SNPs (GGaluGA151406, Gga_rs14554319 and Gga_rs13593979) and candidate genes (LYRM4 and KTN1) were found to be associated with avian influenza antibody titres, and the first two SNPs are from the results of two‐model analysis. For the immune organs, through the analysis of GLM, 19 SNPs were found to be significantly associated with the thymus weight, 61 SNPs were significantly associated with the bursa of Fabricius weight, six of which were located within a 34‐Mb region (125 846 474–159 649 698 bp) on chicken chromosome 1 (GGA1). A candidate region relevant to haematological traits from GLM was found in GGA4 and 9 loci were located on it. Three loci (GGaluGA348521, Gga_rs16098446 and GGaluGA348518) within 179 kb (16 286 868–16 466 134 bp) on GGAZ from GLM provided evidence that this genomic segment may be relevant to red blood cell volume distribution width (RDW). Our study provides a list of significant SNPs and candidate genes that will be valuable information for unveiling the underlying molecular mechanism of immune regulation.     

四川省外种猪ESR基因对繁殖及生长性状的影响

试验以四川省外种母猪的 3个品种 (大约克、长白、杜洛克 )为研究对象 ,采用PCR -RFLps的方法测其ESR基因的PvuⅡ多态性 ,分析了该产仔数及生长性状之间的关系。结果表明 :初产胎次中 ,ESR基因型间总产仔数 (TNB)和产活仔数 (NBA)差异极显著 (P <0 0 1 ) ,BB和AA纯合子间TNB和NBA分别相差 5 97和 3 72头 ,基因加性效应分别应为每个B基因 2 98和 1 86头。对于经产胎次 ,总产仔数在AA ,AB基因与BB基因型的差异达到极显著水平 (P <0 0 1 ) ,产活仔数在AA基因型与BB基因型间差异显著 (P <0 0 5 ) ,TNB和NBA母猪每窝BB纯合子比AA纯合子分别多 3 6 8和 2 89头 ,基因的加性效应为每个B基因分别为 1 83和 1 4 4头。头胎和经产胎次ESR基因型在初生窝重、2 0日龄头数和窝重、30或 4 5日龄头数和窝重以及 70日龄窝重之间的差异不显著 (P >0 0 5 ) ;但是以上 6个性状在ESR基因的 3种基因型间存在BB >AB >AA的趋势     

放牧对贵南县4种退化指示植物叶片性状的影响

本研究以青海省贵南县高寒草甸4种退化指示植物为研究对象,分析放牧干扰对叶片碳(C)、氮(N)、磷(P)含量及其化学计量特征、叶干物质含量和比叶面积的影响,探讨高寒草甸生态系统中退化植物对环境变化的响应和适应策略。结果表明,4种植物叶片碳、氮、磷含量及化学计量比随放牧强度增加表现为碳含量不变,氮、磷含量上升、化学计量比(C/N、C/P及N/P)下降的变化趋势,且重度放牧后,植物生长受氮元素限制。放牧强度改变显著影响4种植物叶片性状(P<0.01),且对叶片磷含量的影响最大(P<0.001);物种对比叶面积影响最大(P<0.001),且在不同植物间表现出物种差异性。即放牧强度增加时,4种植物叶片均表现出养分储存增加,但植物比叶面积的变化更多表现出物种特异性。     

Genetic relationship of body measurement traits at early age with carcass traits in Japanese black cattle

Estimates of genetic parameters were obtained for body measurement traits of 648 animals at 4 months of age, of 545 at 8 months and carcass traits of 14 972 animals with the use of an animal model by the restricted maximum likelihood procedure. The estimated heritabilities for carcass traits were high (0.41 to 0.54). At 4 months the estimated direct heritabilities for body measurement traits were moderate to high (0.28 to 0.64), except for chest width (0.19); at 8 months they were also moderate to high (0.23 to 0.49), except for chest depth and chest width (0.18 and 0.06, respectively). Maternal heritabilities for all body measurement traits were low at both ages. The results indicate that because of their moderate direct genetic correlations with body measurement traits, carcass weight, rib thickness and subcutaneous fat thickness can be improved; however, rib eye area and beef marbling standard show little such possibility considering their correlation with body measurement traits.     

波尔山羊繁殖性状遗传参数的估计

对 2 4 8窝波尔山羊的胎产羔数、羔羊初生重和 2月龄体重的资料进行了遗传分析。结果表明 :公羊和胎次均对母羊产羔数具有显著的影响(P <0 0 5)。不同产羔季节对羔羊初生重和 2月龄体重也具有显著影响。产羔数的遗传力为 0 1 52 ,属低遗传力 ,而羔羊初生重和 2月龄体重 2个性状 (0 433 ,0 347)有中等或较高的遗传力。波尔母羊胎产羔数与羔羊初生重、 2月龄体重之间存在显著或极显著的表型相关 ,但是它们之间却存在显著或极显著的负遗传相关 (P <0 0 5或 P<0 0 1 )。羔羊的初生重和 2月龄体重间 ,无论是表型相关还是遗传相关 ,都呈极显著的正相关(P <0 0 1 )。