山羊MyoD基因家族多态性及与体尺性状的相关性

用PCR-SSCP技术研究了波尔山羊和徐淮山羊2个群体共147个个体MyoD基因家族中3个基因座位的单核苷酸多态性(single nucleotide polymorphism, SNP)。结果表明, 在徐淮白山羊群体中, myf-5基因座发现有3种基因型AA、AB和BB, 波尔山羊均为AA型。在myf-6基因座和myoD 5′侧翼区基因座, 两个山羊群体均检测到了AA和AB型个体。对山羊myf-5、myf-6基因座, myoD 5′侧翼区基因座不同基因型与两品种山羊体尺性状相关分析表明, myf-5基因座对管围和管围指数的效应差异显著(P<0.05)。myf-6基因座对徐淮白山羊体尺性状的效应均不显著(P>0.05), 而对波尔山羊的体高和管围指数效应差异显著(P<0.05)。两个山羊品种myoD 5′侧翼区不同基因型个体的体尺性状差异均不显著。     

牙鲆MyoD基因单核苷酸多态性位点的筛选

运用PCR-SSCP技术研究100尾牙鲆(Paralichthys olivaceus)MyoD基因的单核苷酸多态性(Single nucleotide polymorphisms, SNPs), 并将筛选到的突变位点与牙鲆生长性状进行相关性分析。结果表明, 在外显子1和内含子1上存在3个SNPs, 在外显子1 (MyoD2)基因座发现3种基因型AA、AB和BB, G863A突变, 属于同义突变。在内含子MyoD4基因座检测到DD、FF、CD、CE、DE和DF型个体。利用最小二乘法研究MyoD基因多态性位点对牙鲆生长性状的影响。结果表明, 外显子1的SNPs对生长性状无显著影响(P0.05)。内含子1的SNPs对牙鲆的生长性状影响均显著(P0.05)。研究结果为SNPs位点与牙鲆生长性能关联分析奠定了基础。       

草鱼MyoD基因原核表达研究

中国水产科学研究院、珠江水产研究所、热带亚热带鱼类选育与养殖重点开放实验室、西北农林科技大学动物科技学院、陕西省农业分子生物学重点实验室王立新等和西北农林科技大学、     

中国荷斯坦牛POU1F1基因与PRL基因的多态性及其聚合效应对产奶性状的影响

文章采用DNA测序、PCR-RFLP和CRS-PCR技术对979头中国荷斯坦牛POU1F1基因与PRL基因进行研究,发现了3个新SNPs,分别是POU1F1基因第二外显子G1178C、PRL基因5侧翼区A906G和A1134G。采用SAS统计软件GLM程序,利用最小二乘法拟合线性模型,分析基因多态性与产奶性状的关系。结果表明:POU1F1基因1178位点GC基因型在产奶量、乳蛋白量、乳脂量方面均为优良基因型。PRL基因5侧翼区906位点AG基因型在产奶量方面为优良基因型,1134位点不同基因型产奶性状差异不显著。对PRL基因5侧翼区的906位点和POU1F1基因的1178位点进行基因互作分析,结果在乳脂率、乳蛋白率、产奶量、乳蛋白量和乳脂量方面各基因型组合之间均未观察到显著差异,说明基因聚合效应并不是单基因效应的简单相加,基因聚合效应在分子育种中具有更重要的意义。     

关岭牛MyoD1与MSTN基因相互表达调控

[目的]旨在验证牛MyoD1与MSTN在表达调控上的相互作用.[方法]首先,以构建的pEGFP-N3-MyoD1和EGFP-N3-MSTN过表达载体,分别在两组关岭牛原代成肌细胞中过表达MyoD1和MSTN,细胞转染24h后,qRT-PCR检测并分析各处理组细胞中MyoD1和MSTN相比表达情况.其次,以海肾荧光载体p...     

POU1F1基因的遗传变异对南阳牛生长发育性状的影响

利用PCR-RFLP技术首次研究了南阳牛群体100个个体POU1F1基因多态性及其与体重、体尺等生长性状指标之间的相关性。结果表明,南阳牛群体POU1F1基因座的451bp的PCR产物被限制性酶Hinf Ⅰ消化后表现多态性,它们的等位基因A／B频率为：0．465／0．535,且处于Hardy-Weinberg平衡状态。同时,南阳牛群体POU1F1-Hinf Ⅰ基因座不同基因型与体重、体尺等生长性状指标相关分析的结果表明：南阳牛群体内BB与AB基因型个体在初生重、断奶前平均日增重、六月龄体重、体斜长和胸围以及十二月龄的体重、体高、体斜长和胸围指标上有显著差异,且BB〉AB（P〈0．05）;群体内BB型个体在十二月龄体重指标上显著高于群体的AA型个体,即BB〉AA（P〈0.05）,在其他各年龄段的各项体重和体尺指标上同样呈现出B等位基因高于A等位基因的一种趋势。初步认为BB基因型为优势基因型,相应地B为优势等位基因,对选择有正向效应,提示POU1F1基因的占等位基因可能与高生长发育性状有关。     

牛POMC基因多态性及其与南阳牛生长性状的相关分析

为研究阿片黑皮质素前体(POMC)在动物采食和能量平衡调控中发挥重要作用, 文章采用PCR-SSCP结合DNA测序方法, 对秦川牛、南阳牛、郏县红牛、晋南牛、鲁西牛、安格斯牛和荷斯坦奶牛共计480头个体POMC基因的多态性进行研究, 并分析了多态位点与南阳牛生长性状的相关性。结果表明, 牛POMC基因3个位点中, 在3′侧翼区P3位点新发现3个连锁存在的SNP(811845 C>T、811821 T>C和811797 A>G, 与NW_928357对照)。POMC基因3′侧翼区多态位点与南阳牛6月龄体重和0~6月龄平均日增重显著相关, BB型个体显著大于AA型(P<0.05)。     

猪FUT1基因对肉质和胴体性状的影响

测定139头杂交猪(大白猪和梅山猪)的14个肉质性状和8个胴体性状,用PCR-RFLP方法检测FUT1基因型。分析猪FUT1基因型间肉质和胴体性状差异,发现AA基因型猪3个部位肌肉pH值均比AG基因型的高,其中pH(LD)达到显著水平(P<0.05)。AA基因型猪肌肉系水力显著高于AG猪的系水力(91.02% VS 86.70%,P<0.05)。AA基因型猪的肉色值显著高于AG猪的(P<0.05)。AA基因型猪三个部位肌肉膘厚值均较低,其中最后肋骨膘厚和倒数三四肋骨膘厚分别比AG基因型猪的低4.26 mm和3.96 mm(P<0.05)。AA基因型猪瘦肉率比AG基因型猪的高3.31% (53.46% VS 50.15%,P<0.05)。以上结果表明FUT1基因的AA基因型对肉质和和胴体性状具有显著的正遗传效应,这对于在抗病育种中应用该基因十分有利。     

秦川牛GHR基因SNPs及其与生长性状关系的研究

利用PCR-SSCP技术研究了136头秦川牛GHR基因第10外显子多态性, 所研究的秦川牛群体GHR基因该座位存在多态性, 发现了A、B、C 3个等位基因, 其基因频率依次为0.5956、0.2905、0.1140, 并且群体处于Hardy-Weinberg平衡状态。对纯合基因型个体进行测序, 测序结果, 该座位存在两个突变位点。通过构建最小二乘线性模型, 分析了生长激素受体基因与生长性状的关系, 表明生长激素受体基因的AB基因型效应在部分生长性状上高于其他基因型, 差异达到显著水平, 提示GHR基因有可能作为秦川牛生长性状的侯选基因。     

红罗非鱼MyoD基因克隆及序列分析

MyoD基因是MRFs家族中的一员,能调控肌肉细胞活性和增殖,在肌肉形成过程中起正调控作用。采用同源基因克隆和RACE方法获得红罗非鱼Myo D基因的c DNA序列。开放阅读框长903 bp,编码300个氨基酸,其中第1-114个氨基酸为碱性结构(Basic domain),第109-165个氨基酸为螺旋-环-螺旋结构(Helix-Loop-Helix domain),第199-213个氨基酸为周期蛋白依赖性蛋白激酶4(CDK4)结合区域,第233-249为Helix III结构,无信号肽序列。Myo D蛋白的二级结构为螺旋-环-螺旋二聚体。基于Myo D构建的鱼类系统进化树显示红罗非鱼,尼罗罗非鱼和奥利亚罗非鱼聚为一支。     

Additional support for an association between OLR1 and milk fat traits in cattle

The bovine oxidized LDL receptor 1 (OLR1) was chosen as a candidate gene for association tests with milk composition traits. Genotyping of 773 Italian Brown Swiss for a SNP at position 8232 in OLR1 (NW_215807:g.8232C>A) revealed a frequency of 0.95 for the g.8232C allele. The University of Wisconsin Holstein resource population was genotyped for the OLR1 NW_215807:g.[7160C>T; 7161A>G; 8232C>A] SNPs, and four haplotypes were inferred based on the genotypes of sires and their daughters. Oxidized LDL receptor 1 haplotypes were significantly associated with fat percentage (P = 0.0015). Haplotype [C; A; C] was associated with a significant increase in fat percentage when compared with the other haplotypes.     

Genetic relationships between carcass cut weights predicted from video image analysis and other performance traits in cattle

The objective of this study was to quantify the genetic associations between a range of carcass-related traits including wholesale cut weights predicted from video image analysis (VIA) technology, and a range of pre-slaughter performance traits in commercial Irish cattle. Predicted carcass cut weights comprised of cut weights based on retail value: lower value cuts (LVC), medium value cuts (MVC), high value cuts (HVC) and very high value cuts (VHVC), as well as total meat, fat and bone weights. Four main sources of data were used in the genetic analyses: price data of live animals collected from livestock auctions, live-weight data and linear type collected from both commercial and pedigree farms as well as from livestock auctions and weanling quality recorded on-farm. Heritability of carcass cut weights ranged from 0.21 to 0.39. Genetic correlations between the cut traits and the other performance traits were estimated using a series of bivariate sire linear mixed models where carcass cut weights were phenotypically adjusted to a constant carcass weight. Strongest positive genetic correlations were obtained between predicted carcass cut weights and carcass value (min r_g(MVC) = 0.35; max r_g(VHVC) = 0.69), and animal price at both weaning (min r_g(MVC) = 0.37; max r_g(VHVC) = 0.66) and post weaning (min r_g(MVC) = 0.50; max r_g(VHVC) = 0.67). Moderate genetic correlations were obtained between carcass cut weights and calf price (min r_g(HVC) = 0.34; max r_g(LVC) = 0.45), weanling quality (min r_g(MVC) = 0.12; max r_g(VHVC) = 0.49), linear scores for muscularity at both weaning (hindquarter development: min r_g(MVC) = −0.06; max r_g(VHVC) = 0.46), post weaning (hindquarter development: min r_g(MVC) = 0.23; max r_g(VHVC) = 0.44). The genetic correlations between total meat weight were consistent with those observed with the predicted wholesale cut weights. Total fat and total bone weights were generally negatively correlated with carcass value, auction prices and weanling quality. Total bone weight was, however, positively correlated with skeletal scores at weaning and post weaning. These results indicate that some traits collected early in life are moderate-to-strongly correlated with carcass cut weights predicted from VIA technology. This information can be used to improve the accuracy of selection for carcass cut weights in national genetic evaluations.     

Linkage between amylase-1 locus and a major gene for milk fat content in cattle

Summary
Linkage between the amylase-1 ( Am-1 ) locus and a quantitative trait locus influencing fat content in milk was studied in offspring from heterozygous sires of the Swedish Red and White dairy breed. The effect on bull breeding values for fat content was estimated as interactions between sire and paternal Am-1 allele using a model eliminating the direct effects of sire and Am-1 allele. There were strong indications of linkage, confirming results of previous studies. The interaction was caused by strong associations in 7 out of 14 sire families. A test for within-family variance heterogeneity performed on the whole population of breeding bulls also supported the presence of a major gene for fat content in milk. The results indicate that there is genetic linkage between the Am-1 locus and a locus with large effect on milk fat content.     

Genetic relationship between growth and reproductive traits in Nellore cattle

The objective of this study was to evaluate the genetic relationship between postweaning weight gain (PWG), heifer pregnancy (HP), scrotal circumference (SC) at 18 months of age, stayability at 6 years of age (STAY) and finishing visual score at 18 months of age (PREC), and to determine the potential of these traits as selection criteria for the genetic improvement of growth and reproduction in Nellore cattle. The HP was defined as the observation that a heifer conceived and remained pregnant, which was assessed by rectal palpation at 60 days. The STAY was defined as whether or not a cow calved every year up to the age of 6 years, given that she was provided the opportunity to breed. The Bayesian linear-threshold analysis via the Gibbs sampler was used to estimate the variance and covariance components applying a multitrait model. Posterior mean estimates of direct heritability were 0.15 ± 0.00, 0.42 ± 0.02, 0.49 ± 0.01, 0.11 ± 0.01 and 0.19 ± 0.00 for PWG, HP, SC, STAY and PREC, respectively. The genetic correlations between traits ranged from 0.17 to 0.62. The traits studied generally have potential for use as selection criteria in genetic breeding programs. The genetic correlations between all traits show that selection for one of these traits does not imply the loss of the others.     

Genetic parameters and relationships between growth traits and scrotal circumference measured at different ages in Nellore cattle

Records from 106,212 Nellore animals, born between 1998 and 2006, were used to estimate (co)variance components and genetic parameters for birth weight (BW), average weight gains from birth to weaning (GBW), average weight gains from weaning to after yearling (GWAY), weaning hip height (WHH), postweaning hip height (PHH) and scrotal circumferences at 9 (SC9), 12 (SC12) and 15 (SC15) months of age. (Co)variance components were estimated by an animal model using multi-trait analysis. Heritability estimates for BW, GBW, GWAY, WHH, PHH, SC9, SC12 and SC15 were 0.31 ± 0.01; 0.25 ± 0.02; 0.30 ± 0.04; 0.51 ± 0.04; 0.54 ± 0.04; 0.39 ± 0.01; 0.41 ± 0.01 and 0.44 ± 0.02, respectively. Genetic correlations between growth traits ranged from 0.09 ± 0.01 to 0.88 ± 0.01, thereby implying that, at any age, selection to increase average weight gains will also increase stature. Genetic correlations between BW and average weight gains with scrotal circumferences were all positive and moderate (0.15 ± 0.03 to 0.38 ± 0.01). On the other hand, positive and low genetic associations were estimated between hip height and scrotal circumference at different ages (0.09 ± 0.01 to 0.17 ± 0.02). The results of this study pointed out that selection to larger scrotal circumferences in males will promote changes in average weight gains. In order to obtain Nellore cattle with the stature and size suitable for the production system, both weight gain and hip height should be included in a selection index.     

Genome-wide association study reveals five nucleotide sequence variants for carcass traits in beef cattle

Genetic associations of nucleotide sequence variants with carcass traits in beef cattle were investigated using a genome-wide single nucleotide polymorphism (SNP) assay. Three hundred and thirteen Korean cattle were genotyped with the Illumina BovineSNP50 BeadChip, and 39,129 SNPs from 311 animals were analysed for each carcass phenotype after filtering by quality assurance. Five sequence markers were associated with one of the meat quantity or quality traits; rs109593638 on chromosome 3 with marbling score, rs109821175 on chromosome 11 and rs110862496 on chromosome 13 with backfat thickness (BFT), and rs110228023 on chromosome 6 and rs110201414 on chromosome 16 with eye muscle area (EMA) (P < 1.27 × 10(-6) , Bonferonni P < 0.05). The ss96319521 SNP, located within a gene with functions of muscle development, dishevelled homolog 1 (DVL1), would be a desirable candidate marker. Individuals with genotype CC at this gene appeared to have increased both EMA and carcass weight. Fine-mapping would be required to refine each of the five association signals shown in the current study for future application in marker-assisted selection for genetic improvement of beef quality and quantity.     

Comparison between the three porcine RN genotypes for growth,carcass composition and meat quality traits

A three-step experimental design has been carried out to add evidence about the existence of the RN gene, with two segregating alleles RN^- and rn⁺, having major effects on meat quality in pigs, to estimate its effects on production traits and to map the RN locus. In the present article, the experimental population and sampling procedures are described and discussed, and effects of the three RN genotypes on growth and carcass traits are presented. The RN genotype had no major effect on growth performance and killing out percentage. Variables pertaining to carcass tissue composition showed that the RN^- allele is associated with leaner carcasses (about 1 s.d. effect without dominance for back fat thickness, 0.5 s.d. effect with dominance for weights of joints). Muscle glycolytic potential (GP) was considerably higher in RN^- carriers, with a maximum of a 6.85 s.d. effect for the live longissimus muscle GP. Physico-chemical characteristics of meat were also influenced by the RN genotype in a dominant way, ultimate pH differing by about 2 s.d. between homozygous genotypes and meat colour by about 1 s.d. Technological quality was also affected, with a 1 s.d. decrease in technological yield for RN^- carriers. The RN genotype had a more limited effect on eating quality. On the whole, the identity between the acid meat condition and the RN^- allele effect is clearly demonstrated (higher muscle GP, lower ultimate pH, paler meat and lower protein content), and the unfavourable relationship between GP and carcass lean to fat ratio is confirmed.     

Relationship of growth hormone and insulin-like growth factor-1 genotypes with growth and carcass traits in swine

The contribution of chromosomal regions linked to growth hormone (GH) and insulin-like growth factor-1 (IGF-1) loci to variation in preweaning average daily gain, postweaning average daily gain (ADG), 10th rib backfat, loin-eye area and muscle pH were evaluated. Offspring of four purebred sires (A–D; n = 150, 195, 148 and 136, respectively) and two crossbred sires (E and F; n = 157 and 145, respectively) were genotyped initially with GH and IGF-1 markers. When results of single marker analysis suggested possible linkage with a quantitative trait locus (QTL), additional flanking markers were typed for the family and interval mapping was performed. Growth hormone genotype was not associated with the traits evaluated in the study. Evidence suggestive of linkage was found for IGF-1 genotype and ADG in one sire family (lod = 2·3) where differences were 0.032 ± 0·01 kg/day for alternative sire alleles. Evidence for a putative ADG QTL was greatest in the interval between IGF-1 and Sw1071. A similar genomic region has been associated with growth variation in mice; however, QTL mapping precision in the current study is insufficient to establish similarity.     

FTO gene variants are associated with growth and carcass traits in cattle

An important aim in animal breeding is the improvement of growth and meat quality traits. Previous studies have demonstrated that genetic variants in the fat mass and obesity associated (FTO) gene have a relatively large effect on human obesity as well as on body composition in rodents and, more recently, in livestock. Here, we examined the effects of the FTO gene variants on growth and carcass traits in the Slovenian population of Simmental (SS) and Brown (SB) cattle. To validate and identify new polymorphisms, we used sequencing, PCR‐RFLP analysis and TaqMan assays in the SS breed and FTO gene variants data from the Illumina BovineSNP50 v1 array for the SB breed. Sequencing of the eight samples of progeny‐tested SS sires detected 108 single nucleotide polymorphisms (SNPs) in the bovine FTO gene. Statistical analyses between growth and carcass traits and 34 FTO polymorphisms revealed significant association of FTO variants with lean meat percentage in both breeds. Additionally, FTO SNPs analyzed in SS cattle were associated with fat percentage, bone weight and live weight at slaughter. The FTO gene can thus be regarded as a candidate gene for the marker‐assisted selection programs in our and possibly other populations of cattle. Future studies in cattle might reveal novel roles for the FTO gene in shaping carcass traits in livestock species as well as body composition control in other mammals.