猪IGF2基因外显子4b的遗传多态性及其遗传效应

采用PCR-SSCP方法检测猪胰岛素样生长因子2(insulin-like growth factor 2,IGF2)基因外显子4b的多态性,并分析其对初生重、断奶重、6月龄重和背膘厚的遗传效应。根据猪IGF2基因的DNA序列(AY044828)设计引物,在exon4b上发现了一个多态性位点,并对纯合子进行测序,发现13位C→A转换,且存在3种基因型(AA、AB、BB)。统计结果表明,3种基因型在各品种中的分布不一致,长白猪与大白猪比较,莱芜猪与大薄莲猪比较,沂蒙黑猪和里岔黑猪比较差异不显著(P>0.05);其他猪种间基因型分布的差异均显著(P<0.05)。固定效应模型分析结果表明,初生重,断奶重和背膘厚基因型间差异显著(P<0.05),而6月龄重基因型间差异不显著(P>0.05)。最小二乘分析结果表明,BB基因型个体同AA和AB、基因型个体比较初生重和断奶重的差异显著(P<0.05),3种基因型在初生重和断奶重的大小排列顺序为AA>AB>BB;AA基因型个体同AB和BB基因型个体比较背膘厚的差异显著(P<0.05),3种基因型在背膘厚的大小排列顺序为BB>AB>AA。因此,推测IGF2基因对个体的生长速度和胴体瘦肉率存在一定的影响,将IGF2基因应用于猪育种过程中的标记辅助选择可以加快猪的育种进程。     

秦川牛IGF2基因SNPs检测及其与胴体、肉质性状的相关性

采用PCR-SSCP方法对186头24月龄秦川牛IGF2基因进行了SNPs多态性检测, 并将其与部分胴体和肉质性状进行关联分析。在IGF2基因120碱基处发现C→T 突变, 在279碱基处发现 A→G 突变。方差分析结果表明: BB、DD 两个位点与胴体性状中与宰前活重、胴体重、胴体长、胴体胸深、眼肌面积显著相关(P<0.05), 其中背部皮下脂肪厚达到差异极显著(P<0.01); 与肉质性状大理石花纹、嫩度、pH24 (牛肉排酸24 h后的酸度值)显著相关(P<0.05)。但是在胴体深、系水力指标中差异不显著(P>0.05)。A、D 等位基因是群体中的优势等位基因, AA、DD 基因型是优势基因型, 而含有B、D 等位基因的个体的胴体和肉质性状优于其他个体, 尤其有着极强脂肪沉积能力     

猪IGF-Ⅰ基因的一个遗传多态性及其遗传效应分析

采用PCR-SSCP方法对长白猪(87头)、大白猪(79头)和马身猪(102头)的胰岛素样生长因子-Ⅰ(IGF-Ⅰ)基因外显子3和外显子4分别进行单核苷酸多态性分析.发现外显子3上有多态性,且存在3种基因型(AA、AB、BB).统计结果表明,3种基因型在各品种中的分布不一致,多重比较差异极显著(P＜0.01).固定效应模型分析结果表明,背膘厚基因型间差异显著(P＜0.05),而初生重、断奶重和6月龄重基因型间差异不显著(P＞0.05).最小二乘分析结果表明,BB基因型与其它2种基因型比较有较大的初生重,同AA和AB型比较差异极显著(P＜0.01),3种基因型在初生重的大小排列顺序为AA＜AB＜BB;BB基因型与AA基因型比较有较小的背膘厚,且差异极显著(P＜0.01).因此,推测IGF-Ⅰ基因对个体的初生重和胴体瘦肉率存在一定的影响.选择带有B等位基因的个体,有望提高个体的初生重和胴体的瘦肉率.     

猪UCP3基因部分编码区序列分析及其单核苷酸多态与胴体、肉质性状的遗传效应

以猪解耦联蛋白基因 3(UCP3)作为控制猪胴体与肉质性状主基因的候选基因。利用直接测序法对 4个品种猪骨骼肌中UCP3基因的部分编码区序列 (第 4外显子部分及第 5、6、7外显子全部片段 )进行比较分析 ,发现3个cSNP位点 ,其中ORF中第 84 2碱基的突变可导致相应编码氨基酸序列的改变 :甲硫氨酸→苏氨酸 ,选取此位点作为猪UCP3基因的多态位点。用PCR SSCP检测方法在 3个品种猪中进行该cSNP位点多态性片段的基因型分型 ,结果显示在 3个猪群中表现出 3种基因型 (AA、AB、BB) ,χ2 独立性检验结果表明 3种基因型在各品种间分布不一致 ,梅山猪同大白、长白猪分别比较差异极显著 (P <0 0 1) ;对大白×梅山资源家系F2 代 139头个体进行了该多态片段的基因型鉴定 ,并对其基因型与所检测个体相应的胴体、肉质性状采用GLM分析进行遗传效应研究 ,结果表明 :该基因对一些胴体、肉质性状有显著性影响 ,并且该基因以加性效应为主 (如 ,眼肌高度、背最长肌色值、系水力的加性效应都达显著水平 )。因此 ,推测UCP3基因可能是影响猪胴体及肉质性状的主效基因或与主效基因紧密连锁的标记基因 ,并且能够在分子标记辅助选择中用于对猪胴体、肉质性状的遗传改良及固定     

秦川牛脂联素基因SNPs检测及其与胴体、肉质性状的相关性

利用PCR-SSCP结合测序技术对405头24月龄秦川牛脂联素基因SNPs位点进行检测, 运用SPSS统计程序中的GLM模型将检测到的SNPs位点与部分胴体及肉质性状的相关性进行了分析。结果检测到AA、AB、BB、CC、CD 5种基因型, 其中AB、BB型个体在脂联素基因第2外显子 64 bp处发现G→C突变, CD型个体第3外显子50 bp处发现C→T的突变, G→C导致谷氨酸(GGA)转化为谷氨酰胺(GCA), C→T导致丝氨酸(TCA)转化为亮氨酸(TTA)。方差分析结果表明: AA型个体的宰前活重、胴体重、眼肌面积显著高于BB型(P<0.05), 而在胴体腿臀围方面, AA型个体极显著高于AB型、BB型个体(P<0.01)。CD型个体的宰前活重、胴体腿臀围、皮下脂肪厚、背膘厚、嫩度都显著优于CC型个体(P<0.05)。脂联素基因该位点可能是影响秦川牛胴体及肉质性状的主效QTL或与之紧密连锁, 可作为秦川牛高档牛肉生产的候选分子标记。     

猪肌细胞生成素基因对部分生长性状的影响

采用PCR-SSCP方法对长白猪、大白猪、杜洛克猪、山西黑猪和马身猪的肌细胞生成素（Myogenin,简称MyoG）基因进行单核苷酸多态性检测,并分析MyoG基因对猪的初生重、断奶重、6月龄重和背膘厚的影响。根据猪MyoG基因的DNA序列设计10对引物,发现In2-3引物扩增的片段有多态性。统计结果发现,3种基因型（AA、AB、BB）在各品种中的分布不一致。χ^2独立性检验表明,基因型频率在外来猪种（长白猪、大白猪、杜洛克猪）与地方猪种（山西黑猪、马身猪）间存在显著差异（P〈0．05）。固定效应模型分析结果表明,初生重和背膘厚基因型间差异显著（P〈0．05）,而断奶重和6月龄重基因型间差异不显著（P〉0．05）。最小二乘分析结果表明,BB基因型与其他两种基因型比较有较小的初生重,同AA和AB型比较差异极显著（P〈0．01）,3种基因型在初生重的大小排列顺序为AA〉AB〉BB;AA基因型与其他两种基因型比较有较小的背膘厚,同AB和BB型比较差异极显著（P〈0．01）,3种基因型在背膘厚的大小排列顺序为AA〈AB〈BB。因此,推测基因型对个体的初生重和胴体瘦肉率存在一定的影响,选择带有A等位基因的个体有望提高个体的初生重和胴体的瘦肉率。     

早胜牛类群A-FABP基因SNPs及其与胴体品质和肉质性状的相关性分析

研究早胜牛类群A-FABP基因多态性及其与胴体品质和肉质性状的相关性。采用PCR-SSCP方法对5个早胜牛类群(庆阳类群、平凉类群、南德温与庆阳类群杂种、西门塔尔与平凉类群杂种、秦川牛与平凉类群杂种)的A-FABP基因进行多态性分析,分析基因型与胴体品质和肉质性状的相关性。结果显示,A-FABP基因第三外显子区存在c.408GC的突变,并检测到3种基因型GG、GC和CC。胴体性状相关分析表明,GG基因型的胴体重显著低于CC基因型(P0.05);GG基因型屠宰率极显著低于GC基因型(P0.01),显著低于CC基因型(P0.05);GG基因型净肉率显著低于GC基因型(P0.05);GG基因型的眼肌面积显著低于GC和CC基因型(P0.05)。肉质性状相关分析表明,GG基因型失水率显著高于CC基因型个体(P0.05);GG基因型剪切力极显著高于GC和CC基因型(P0.01);GG基因型蒸煮损失和pH均显著高于GC基因型(P0.05),极显著高于CC基因型(P0.01)。A-FABP基因突变位点可作为胴体性状和肉质性状遗传标记。     

猪IGF2基因的遗传多态性及其遗传效应分析

采用PCR-SSCP方法检测胰岛素样生长因子2 (insulin-like growth factor 2, IGF2)基因外显子7, 8, 9的多态性, 并分析其对初生重、断奶重、6月龄重和6月龄背膘厚的遗传效应。根据猪IGF2基因的DNA序列(AY044828)设计3对引物, 结果在Ex8引物对扩增的片段上发现了多态性, 并对纯合子进行测序, 发现exon8的53位存在C→T转换, 且检测到3种基因型(AA、AB、BB)。统计结果表明, 3种基因型在各品种中的分布不一致, 长白猪与大白猪比较, 莱芜猪与大薄莲猪比较, 沂蒙黑猪和里岔黑猪比较差异不显著(P > 0.05); 其他猪种间基因型分布的差异均显著(P < 0.01)。固定效应模型分析结果表明, 初生重和6月龄背膘厚基因型间差异显著(P < 0.05), 而断奶重和6月龄重基因型间差异不显著(P > 0.05)。最小二乘分析结果表明, BB基因型个体同AA和AB基因型个体比较初生重的差异显著(P < 0.05), 3种基因型在初生重的大小排列顺序为AB > AA > BB; AA基因型个体同AB和BB基因型个体比较6月龄背膘厚的差异显著(P < 0.05), 3种基因型在6月龄背膘厚的大小排列顺序为BB > AB > AA。因此, 推测IGF2基因对个体的初生重和胴体瘦肉率存在一定的影响, 将IGF2基因应用于猪育种过程中的标记辅助选择可以加快猪的育种进程。     

丙酸通路基因多态性与猪肉质及胴体性状的关联分析

为了挖掘新的猪肉品质及胴体性状的候选基因,揭示猪肉质及胴体性状的遗传机制,文章将丙酸代谢通路作为候选通路,将通路内基因与猪肉质及胴体性状进行关联分析。实验采用37头三元杂交商品猪作为研究对象,首次针对丙酸通路中7个基因的36个SNP位点利用SNaPshot方法进行基因分型,分别用最小二乘模型及MB-MDR模型与肉质及胴体性状进行关联分析。结果发现,基因PCCB、MUT、MCEE及ACSS2上的4个SNP位点分别与肌内脂肪含量、背膘厚等性状显著相关(P<0.05),ACSS2与猪脂肪含量显著相关;MCEE及MUT与猪的背膘厚显著相关;PCCB基因与脂重显著相关。通过MB-MDR方法检测到多个SNP位点具有互作效应,并与背膘厚、水分含量、脂肪含量显著相关(P<0.05)。另外,丙酸代谢通路中的基因间的互作效应对猪肉品质有显著影响。     

家猪Atrn基因与微卫星标记遗传连锁及对经济性状效应的分析

以杂种近交培育的丹麦资源家系 0～ 5世代中的 174头猪为实验材料 ,以杂交合成的湘黄猪第 9世代的12 9头猪为对照 ,采用PCR RFLP技术 ,检测家猪Atrn基因多态性并分析其对生长和体组成性状的影响。结果表明 :PCR产物经TaqⅠ限制酶消化 ,两猪种均能得到AA、AB、BB 3种基因型 ,基因型频率在猪种间存在极显著差异 (P <0 0 1)。资源家系资料经CRI MAPV2 4软件作连锁分析 ,发现Atrn基因座与 17号染色体SW10 31位点连锁 ,重组率和LOD值分别为 0 2 1和 3 19。应用多变量最小二乘分析模型 ,资源家系的日均屠宰重、背膘厚和湘黄猪的日增重、背膘厚、瘦肉率等性状基因型间均差异显著 (P <0 0 5或P <0 0 1) ,主要为BB基因型个体优于AA和AB基因型个体。由此可见 ,等位基因B对重要经济性状会产生良好效应或选择BB基因型会获得对重要经济性状的良好效应 ,为Atrn基因作为家猪胴体及生长性状候选基因提供了理论依据     

Evaluation of M307 of <Emphasis Type="Italic">FUT1</Emphasis> gene as a genetic marker for disease resistance breeding of sutai pigs

Alpha (1,2) fucosyltransferase (FUT1) gene has been identified as a candidate gene for controlling the expression of the receptor for ETEC F18. The genetic variations in the position of M307 nucleotide in open reading frame of FUT1 have been proposed as a marker for selecting ETEC F18 resistant pigs. The polymorphisms of M307 in FUT1 of breeding base group for ETEC F18 resistance of Sutai pigs (Duroc × Meishan) was detected and their correlations to some immune indexes, growth and development ability, carcass traits and meat quality were also analyzed, which aimed to investigate feasibility of further breeding for diseases resistance based on M307 of FUT1 for Sutai pigs. After digested by Hin6 I, M307 of FUT1 gene could be divided into three kinds of genotypes, AA, AG, and GG. The frequencies were 0.235, 0.609, and 0.156, respectively. The results indicated that Sutai pigs with the AA genotype in M307 of FUT1 gene not only have relatively strong general disease resistance ability in piglets, but also have higher growth and development ability and stable carcass traits and meat quality. It is entirely feasible to raise the new strains of Sutai pigs resistant to Escherichia coli F18 based on genetic marker of the M307 position in FUT1gene.     

Myf-6基因在不同猪种中的PCR-RFLP遗传多态性及其遗传效应分析

作为生肌调节因子家族的一个成员,Myf-6基因在肌形成的过程中发挥着重要的作用。实验采用PCR-RFLP技术分析了Myf-6基因在12个中外猪种及部分杂交群体中的分布情况,并分析了Myf-6基因对肌纤维、胴体品质、胴体等级性状和肉质性状的遗传效应。结果表明：Myf-6基因内含子1内的Ava I酶切位点多态性不丰富,多数中国地方猪种群体中A等位基因已经完全固定,B等位基因仅以较低的频率存在于外种猪或含外种猪血缘的杂交群体中。尽管没有检测到BB纯合个体,但AB杂合子的平均瘦肉率为50.344 %,极显著地高于AA纯合子的45.875 %(P<0.01)。AB杂合子的眼肌面积为27.097 cm2,极显著地大于AA纯合子的22.572 cm2(P<0.01)。AB杂合子的皮脂率（39.889 %）极显著地低于AA纯合子（44.503 %）(P<0.01)。上述结果说明本次试验群体中的B等位基因具有增加胴体瘦肉率和眼肌面积,降低胴体脂肪含量从而改善胴体品质的遗传效应。此外,Myf-6基因对肌纤维生长性状、FOM肉脂仪测定的胴体等级性状以及肉质性状等都没有显著影响(P>0.05)。     

兔黑素皮质素受体4(MC4R)基因多态性及其与体重及屠体性状的关联研究

以哈尔滨白兔、天府黑兔、比利时兔、齐卡巨型兔以及加利福尼亚兔5个肉兔品种共220个个体为研究对象, 采用PCR-SSCP技术和克隆测序技术进行SNPs检测和基因型的分析。结果发现兔MC4R基因237位发生转换突变(A→G), 5个品种内的AA基因型和A等位基因频率均分别高于AG基因型和G等位基因, 而哈尔滨白兔、比利时兔以及齐卡巨型兔3个品种兔的AG基因型频率和G等位基因频率明显高于天府黑兔和加利福尼亚兔。单位点基因型与屠体性状、饲料转化率以及熟肉率的最小二乘分析表明; AG基因型与兔的体重、全净膛重以及饲料转化率有显著的关系(P<0.05), 而与熟肉率的关系不显著(P>0.05)。结果表明, MC4R基因可以作为影响和控制兔体重及屠体性状的候选基因。     

IGFBP3基因多态性与秦川牛部分屠宰性状的相关性 Polymorphisms of Insulin-like Growth Factor Binding Protein 3 Gene and Its Associations with Several Carcass Traits in Qinchuan Cattle

以IGFBP3基因作为秦川牛（Bos taurus）部分屠宰指标的侯选基因,在对60头秦川牛的IGFBP3基因进行PCR-RFLP和序列分析的基础上,对秦川牛群体中IGFBP3基因座等位基因和基因型频率的分布及其与秦川牛部分屠宰性状的关系进行了分析。结果发现,在秦川牛群体中,651 bp的PCR 产物经过限制性内切酶HaeIII消化后,表现出3种基因型,其中等位基因A、B及3种基因型AA、AB、BB的频率分别为0.84、0.16和070、0.28、0.02。经序列分析发现,第299位的C→A颠换（GGCC变成了GGAC）导致了1个HaeIII限制性酶切位点的丢失而产生了该基因座多态性。在所研究的群体中,该多态基因座处于Hardy-Weinberg平衡状态（P＞005）。对13头24月龄秦川牛进行屠宰分析,发现不同基因型对秦川牛部分屠宰指标有一定影响,AA、AB及BB型个体的屠宰率、净肉率及西冷、牛柳、眼肉和嫩肩肉的产率逐渐降低,但差异不显著（P＞0.05）;AA型个体的眼肌面积大于BB型个体（P＜0.05）,AB型和BB型个体胴体脂肪含量高于AA型个体（P＜0.01）。 Abstract:DNA samples from 60 Qinchuan cattle (Bos taurus) were analyzed with PCR-RFLPs and sequencing for insulin-like growth factor binding protein 3 (IGFBP3) gene.Fragments of 651 bp were amplified with two primers and the products of PCR were digested with restriction endonuclease HaeIII.The produced fragments showed three genotypes,namely AA,AB and BB after electrophoresis.Frequencies of the genotype AA,AB,BB and allele A,B were 0.7,0.28,0.02,and 0.84,0.16,respectively.Sequence analysis showed that a transversion of C→A at 299 nt resulted in loss of the cleaved site of restriction endonuclease HaeIII and produced this polymorphism.This polymorphic locus of IGFBP3 gene was at Hardy-Weinberg equilibrium (P＞0.05).The genotypes of AA,AB,BB slightly affected several slaughter and carcass traits of Qinchuan cattle.Dressing percentage,net meat percentage,striplion percentage,tenderloin percentage,ribeye percentage and tender shoulder percentage were decreased with the genotypes of AA,AB and BB in Qinchuan cattle,but it was not significant (P＞0.05).Average ribeye area in individuals of AA genotype was significantly higher than that in individuals of BB genotype (P＜0.05),and beef fat content in individuals of genotype AB and BB was significantly higher than that in individuals of AA genotype (P＜0.01).     

Polymorphism of M307 of the FUT1 Gene and Its Relationship with Some Immune Indexes in Sutai Pigs (Duroc????Meishan)

The alpha (1,2)fucosyltransferase (FUT1) gene has been identified as a candidate gene for controlling the expression of the enterotoxigenic Escherichia coli (ETEC) F18 receptor. Polymorphisms were detected at the M307 position in FUT1 of a breeding base population of Sutai pigs and their correlations to immune parameters analyzed. After digestion by Hin6I, three genotypes were identified at M307, AA (frequency 0.235), AG (0.609), and GG (0.156), with significant deviation from Hardy-Weinberg equilibrium (P < 0.01). The hemoglobin and white blood cell count of the AA genotype pigs were significantly higher than those of AG and GG pigs (P < 0.05). The results indicated that AA pigs not only are resistant to edema disease and post-weaning diarrhea in piglets but also have relatively strong resistance to disease in general.     

鸭前胰岛素原基因多态性及其与屠体性状的关联分析

以384只北京鸭 (Z2系、Z4系、Z2×Z4杂交系)和樱桃谷鸭为材料, 利用PCR-SSCP结合测序技术, 对前胰岛素原基因外显子2与部分内含子的多态性进行了研究, 并分析对屠体性状的遗传效应。结果发现存在2个单核苷酸突变位点, 即在第179位和第195位分别发生了T→C和C→T的突变。适合性χ2检验结果表明, 北京鸭各品系和樱桃谷鸭均处于Hardy-Weinberg平衡状态(P>0.05)。最小二乘分析SNPs与屠体性状的关系表明, 在北京鸭3个品系中, 基因型 BB 在胴体重、全净膛重和胸肌重上极显著(P<0.01)高于基因型AA和AB, 在腿肌重和皮脂重上极显著(P<0.01)高于基因型AB; 基因型AA在皮脂率和全净膛重上极显著(P<0.01)和显著(P<0.05)高于基因型AB。而对于樱桃谷鸭, 只有AB型在皮脂重和腹脂重上显著(P<0.05)高于基因型AA。研究结果表明, 鸭前胰岛素原基因多态性与鸭的部分屠体性状存在显著相关性, 且B等位基因有利于增加鸭的胴体重和胸肌重。     

Association between a single nucleotide polymorphism in the bovine chemerin gene and carcass traits in Qinchuan cattle

Qinchuan is a red or yellow draft and beef breed in China. In order to identify a predictor of carcass traits on the basis of associations between carcass traits and gene polymorphism, variation in the bovine chemerin gene was investigated using PCR-single-strand conformational polymorphism and DNA sequencing. An SNP of A868G located in exon 2 of the Bos taurus chemerin gene was detected in 716 samples of six breeds (Jiaxian red, Luxi, Nan yang, Qinchuan, Simmental and Luxi crossbred steers, and Xia'nan), all in China, and three genotypes (AA, AG and GG) were found. Based on the χ(2) test, the AA/AG/GG genotype frequencies of all six breeds were found to be in Hardy-Weinberg equilibrium. A possible association of A868G with some carcass traits was investigated in 106 Qinchuan cattle. Animals with the AG genotype were found to have significantly lower mean loin eye area and meat tenderness compared to those with the AA and GG genotypes. However, there was no significant association between any individual haplotype and backfat thickness, water holding capacity or marbling score. We suggest that A868G could be used as a molecular marker in marker-assisted selection for carcass traits.     

The Asp298Asn missense mutation in the porcine melanocortin-4 receptor ( MC4R) gene can be used to affect growth and carcass traits without an effect on meat quality

A promising tool to improve daily gain in pigs is the missense mutation (Asp298Asn) in the melanocortin-4 receptor (MC4R) gene, especially in the Belgian pig industry where the slow-growing Piétrain breed is very frequently used as the sire breed. The MC4R is expressed in the appetite-regulating region of the brain where it regulates feed intake and energy balance. The mutation has been associated with differences in fatness, daily gain and feed intake. However, less information on the correlated effects on meat quality is available. In order to evaluate the influence of the MC4R mutation on carcass and meat quality parameters, a total of 1155 pigs of a four-way cross were slaughtered at an average live weight of 109 kg, and data about daily live-weight gain, carcass and meat quality were collected. Allelic frequencies were 0.69 for the G-allele (298Asp variant or well-conserved variant) and 0.31 for the A-allele (298Asn variant or the mutated variant). Barrows and gilts were almost equally distributed in this population with, respectively, 49.9% and 50.1%. Moreover, independent of this mutation, the relationship between average daily gain (ADG) and carcass on the one hand and meat quality traits on the other hand was evaluated in this population. A significant positive influence of the MC4R mutation on ADG (P < 0.001) was found, accompanied by a higher fat thickness (P < 0.05) and a lower carcass lean meat content (P < 0.01), whereas muscle thickness and carcass conformation traits were not affected. The effects on meat quality traits were not significant, except for a lower shear force (P = 0.054) and a higher intramuscular fat content (P = 0.052) in AA animals. In the longissimus, pH and pork quality meter (PQM) values were not influenced, and effects on drip loss and colour were not apparent. Residual correlation coefficients between ADG and carcass lean meat content on the one hand and meat quality traits on the other hand were generally very low (|r|>0.1). Higher ADG, higher carcass fat thickness and lower carcass lean meat content were correlated with slightly lower shear force values (|r|～0.1, P < 0.05). In conclusion, in the studied population, the Asp298Asn mutation in the MC4R gene was associated with improved daily gain, higher carcass fatness and almost no effect on meat quality traits.