No major effect of the leptin gene polymorphism on porcine production traits

Porcine leptin gene (LEP) and its association with production traits was analysed in the Polish Large White (PLW, n = 135), Polish Landrace (PL, n = 120) and synthetic line 990 (L990, n = 184). Two fragments of exon 3 of LEP were studied with the use of RFLP and SSCP techniques. The frequencies of C allele for the T3469C polymorphic site were 0.11, 0.10 and 0.11 in PLW, PL and L990, respectively. Phenotypic data were collected for the average daily weight gain, the feed conversion ratio, the weight of abdominal fat, backfat thickness (five measurements), intramuscular fat, meat content, loin weight, loin muscle area, ham weight and ham cut weight. The contrasts between TT and TC genotypes at the T3469C polymorphic site were estimated in the unitrait Animal Model with genotype at the RYR1 locus included. The lowest p values occurred for association test between T3469C polymorphism and intramuscular fat content in PLW (0.26 ± 0.14%, p = 0.05) and loin weight in L990 (?0.32 ± 0.13 kg, p = 0.01). We conclude that the detected associations are population‐specific and the analysed polymorphism of the LEP gene does not contribute directly to genetic variability of growth and carcass traits in pigs.     

The Association Analysis Between the SNPs of Leptin Gene and Litter Size Trait in Pigs

The research was aimed to analyze the association of Leptingene and breed traits on pigs. Three pairs of primers were designed which based on DNA sequence of pig Leptin gene (GenBank accession No.U66254, AF026976),the single nucleotide polymorphisms (SNPs) of Leptin gene were detected by PCR-SSCP in Sujiang and Jiangquhai pigs. The results showed that three genotypes of AA,AB and BB were identified, and the mutation (T3469C) in CDS of Leptin gene was found,but amino acid change weren't happened. The Chi-square test results showed that the Leptin genotype distribution of Sujiang and Jiangquhai pigs was in Hardy-Weinberg equilibrium (P>0.05). The polymorphism information content (PIC) were moderate polymorphism in Sujiang pigs,and low polymorphism in Jiangquhai pigs. The statistic analysis results showed that there were no significant association between the SNP of Leptin genotype and litter size trait(P>0.05). But the average litter size of T3469C site AB genotype was higher than AA and BB genotypes, it was concluded that the T3469C polymorphism of Leptingene might be the genetic marker which potentially affected pig breed traits.     

猪Leptin基因多态性及其与产仔性状的相关性分析

试验旨在探究Leptin基因对猪产仔性状的影响,为其新品种持续选育提供遗传学依据。参考GenBank发布的猪Leptin基因DNA序列（登录号:U66254、AF026976）设计3对引物,采用PCR-SSCP技术分析Leptin基因在苏姜猪和姜曲海猪中的单核苷酸多态性（SNP）,并用统计学方法分析基因座多态性与产仔性状的相关性。结果发现,Leptin基因在苏姜猪、姜曲海猪群体中均具有多态性,检测到3种基因型:AA、AB和BB;测序结果发现,编码区第3 469位碱基处发生单碱基突变（T3469C）,为同义突变。χ²适合性检验显示,2个猪种Leptin基因型分布处于Hardy-Weinberg平衡（P>0.05）。多态信息含量（PIC）分析显示,苏姜猪为中度多态,姜曲海猪为低度多态。Leptin基因型与产仔性状关联分析显示,不同基因型间产仔性状差异不显著（P>0.05）,但T3469C位点AB基因型平均产仔数较AA和BB基因型高,初步推断Leptin基因T3469C位点可能是影响猪产仔性状潜在的遗传标记,建议做进一步的研究。     

Plasma leptin levels in pigs with different leptin and leptin receptor genotypes

A C3469T mutation at exon 3 of the pig leptin (Lep) gene has been genotyped in diverse pig breeds yielding controversial results with regard to its association with growth, fatness and carcass traits. A similar situation has been reported for a HpaII restriction fragment length polymorphism (RFLP) in the pig leptin receptor (Lepr) gene, where associations were found depending on the statistical model employed. The main objective of our work was to investigate if leptin plasma concentrations differ in pigs with different C3469T and Lepr HpaII RFLP genotypes. With this aim, we have measured plasma leptin levels at 160 days in 68 Landrace pigs with different Lep C3469T and Lepr HpaII RFLP genotypes. Neither Lep (TT: 11.68 ng/ml, TC: 10.71 ng/ml) nor Lepr (AA: 12.6 ng/ml, AB: 10.93 ng/ml, BB: 11.74 ng/ml) genotypes influenced significantly plasma Lep concentration. Moreover, we did not find any association between Lep and Lepr genotypes and phenotypic variation at growth and fatness traits in a commercial population of 320 Landrace pigs.     

Association Analysis Between Polymorphism of IGF1 Gene and Growth Traits in Rabbit

This study was aimed to analyze the association of insulin-like growth factor 1 (IGF1) gene polymorphisms with growth traits in rabbit. The technology of DNA pooling, PCR-SSCP and direct sequencing were used to detect the SNP of IGF1 gene. The results showed that T365C was detected in IGF1 gene exon 3 of rabbit. The SNP (C/T) was devised into three genotypes:TT, TC and CC. The relationships between genotypes and growth traits revealed that the birth weight and the weight at 28 days of age in New Zealand rabbit of TT genotype of T365C locus were significantly higher than TC and CC genotypes (P<0.05), the birth weight, the weight at 90 days of age and average daily gain form birth to 90 days of age in Belgian rabbit of TT genotype of T365C locus were significantly higher than TC and CC genotypes (P<0.05), there were no significant difference of the growth traits in other rabbit breeds (P>0.05).The consequence indicated that IGF1 gene was primarily deduced to be a potential major gene or linked to major gene effecting the growth traits of rabbit, and this SNP (T365C) might be a candidate molecular genetic markers to improve the growth traits of rabbit.     

An age-dependent association between a leptin C3469T single nucleotide polymorphism and intramuscular fat content in pigs

The objective of this work was to investigate whether the C3469T mutation at exon 3 of the pig leptin (Lep) gene is associated with fatness and if the magnitude and direction of these associations is consistent within age. Repeated measurements on body weight (BW), ultrasonic subcutaneous backfat (SB) and loin-muscle (LT) thickness, and intramuscular fat (IMF) content and composition were taken at 160, 180, 215 and 225 days of age on 162 Duroc barrows previously genotyped for the C3469T mutation. Plasma leptin concentration was determined at 180 days. A total of 505 records of IMF content and composition, which were determined both in live samples of longisimus dorsi muscle (LM) and in carcass samples of LM and gluteus medius muscle, were used in the analyses. The genotypic frequencies associated with the C3469T Lep mutation were 0.76, 0.23, and 0.01 for TT, TC, and CC genotypes, respectively. The effect of the Lep genotypes was assessed using a Bayesian approach based on a polynomial mixed model on age. No evidence was found for an association of the Lep genotypes neither with BW, SB thickness nor with plasma leptin concentration. The posterior mean of the difference TT–TC ranged, for LT, from 0.82 (160 days, posterior probability density (PP)> 0 of 87%) to 1.98 mm (220 days, PP > 0 of 96%) and, for IMF, from 0.96 (160 days, PP > 0 of 84%) to − 1.64 mg/g DM (220 days, PP > 0 of 2%). The results suggest an age-dependent association of the C3469T Lep polymorphism with LT and IMF, which may be useful to explain some controversial results in the literature concerning the association of this polymorphism with IMF content.     

Polymorphisms in the bovine leptin promoter associated with serum leptin concentration, growth, feed intake, feeding behavior, and measures of carcass merit

Leptin is the hormone product of the obese gene synthesized and secreted predominantly by white adipocytes. It functions as a lipostatic signal regulating BW, food intake, energy expenditure, reproduction, and certain immune system functions. Although previous studies have identified polymorphisms in the coding regions of the leptin gene in cattle that show considerable associations with feed intake, milk quality and quantity, and carcass fatness, no such associations have been reported for the leptin promoter. The current study reports associations between SNP in the 5' untranslated promoter region of the bovine leptin gene with serum leptin concentration, growth, BW, feed intake, feeding behavior, and carcass merit in hybrid cattle (n = 150). The study showed that animals with the TT genotype of a less frequent cytosine/thymine (C/ T) substitution (UASMS2; frequency of thymine allele equals 0.21) detected at position 528 in the bovine leptin promoter (GenBank Accession No. AB070368) show 48 and 39% increases in serum leptin concentration (P < 0.001), 39 and 31% increases in backfat thickness (P < 0.001), and 13 and 9% increase in marbling score (P = 0.01), compared with CC or CT genotypes, respectively. Animals with the TT genotype also show significantly higher feed intake (P < 0.001), growth rate, metabolic BW (P < 0.05), and live weight at slaughter (P < 0.10). Animals with the GG genotype of a more frequent cytosine/guanine (C/G) substitution (UASMS3; frequency of G allele equals 0.59) at position 1759 in the bovine leptin promoter (GenBank Accession No. AB070368) also show higher feed intake (P = 0.001), growth rate (P < 0.10), and BW (P < 0.01). The thymine allele of UASMS2 and the guanine allele of UASMS3 were separately associated with higher feeding duration (P < 0.05). The two SNP show significant linkage disequilibrium and could also be relevant in predicting other characteristics, such as milk yield and quality in cattle. These results, however, represent the initial associations of the polymorphisms with these traits, and further efforts are required to validate these findings in other populations.     

家兔IGF1基因多态性与生长性状的关联分析

本研究旨在探讨胰岛素样生长因子1（insulin-like growth factor 1,IGF1）基因SNP与家兔生长性状的关联性。采用DNA池、PCR-SSCP方法对家兔IGF1基因的外显子进行多态性检测,结果发现,在家兔IGF1基因的外显子3中检测到1个SNP位点T365C,表现为3种基因型：TT、TC和CC。IGF1基因不同基因型与家兔生长性状的关联分析结果发现,新西兰兔TT基因型个体的初生重、28日龄体重均显著高于TC和CC基因型个体（P<0.05）;比利时兔TT基因型个体的初生重、90日龄体重和初生至90日龄的平均日增重均显著高于TC和CC基因型个体（P<0.05）;其余品种的各生长性状指标在该位点均没有达到显著水平（P>0.05）。结果提示,IGF1基因可能是影响家兔生长性状的主效基因或与主效基因连锁,T365C位点有望作为提高家兔个体生长性状的分子遗传标记。     

Genetic associations of visual scores with subsequent rebreeding and days to first calving in Nellore cattle

Records of Nellore animals born from 1990 to 2006 were used to estimate genetic correlations of visual scores at yearling (conformation, C; finishing precocity, P; and muscling, M) with primiparous subsequent rebreeding (SR) and days to first calving (DC), because the magnitude of these associations is still unknown. Genetic parameters were estimated by multiple‐traits Bayesian analysis, using a nonlinear (threshold) animal models for visual scores and SR and a linear animal models for weaning weight (WW) and DC. WW was included in the analysis to account for the effects of sequential selection. The posterior means of heritabilities estimated for C, P, M, SR and DC were 0.24 ± 0.01, 0.31 ± 0.01, 0.30 ± 0.01, 0.18 ± 0.02 and 0.06 ± 0.02, respectively. The posterior means of genetic correlations estimated between SR and visual scores were low and positive, with values of 0.09 ± 0.02 (C), 0.19 ± 0.03 (P) and 0.18 ± 0.05 (M). On the other hand, negative genetic correlations were found between DC and C (?0.11 ± 0.09), P (?0.19 ± 0.09) and M (?0.16 ± 0.09). The primiparous rebreeding trait has genetic variability in Nellore cattle. The genetic correlations between visual scores, and SR and DC were low and favourable. The genetic changes in C, P and M were 0.02, 0.03 and 0.03/year, respectively. For SR and DC, genetic trends were 0.01/year and ?0.01 days/year, respectively, indicating that the increase in genetic merit for reproductive traits was small over time. Direct selection for visual scores together with female reproductive traits is recommended to increase the fertility of beef cows.     

长白猪prepro-orexin基因多态性及其与采食和生长性状的关联分析

为揭示食欲素前体（prepro-orexin）基因对长白猪采食和生长性状的影响,试验采用PCR产物直接测序法对132头长白猪prepro-orexin基因的C62T和G426A位点多态性进行检测,并对各位点与30~100 kg阶段的采食及生长性状进行关联分析。结果表明,长白猪prepro-orexin基因C62T和G426A位点均处于Hardy-Weinberg平衡状态,等位基因频率表现为野生型（C、G）高于突变型（T、A）;两个位点的4种单倍型和7种单倍型组合中,CG、TA为主要单倍型,CG/CG、TA/CG和TA/TA为主要单倍型组合。C62T位点的CC基因型、G426A位点的GG基因型及CG/CG单倍型组合均可显著减少日采食次数、延长每次采食时间和提高每次采食量（P < 0.05）;其中CG/CG组合的日采食次数、每次采食时间、每次采食量分别较TA/CG组合显著减少1.22次、延长0.79 min和提高32.18 g（P < 0.05）,而与TA/TA组合的差异未达到显著水平（P > 0.05）。C62T位点的TT基因型、G426A位点的AA基因型及TA/TA单倍型组合可显著或极显著缩短达100 kg体重日龄、提高30~100 kg平均日增重（P < 0.05;P < 0.01）;TA/TA组合达100 kg体重日龄分别较CG/CG、TA/CG组合分别显著缩短6.23和6.69 d（P < 0.05）,平均日增重分别极显著提高47.91和50.04 g/d（P < 0.01）。结果表明,prepro-orexin基因C62T和G426A位点对长白猪采食和生长性状的影响具有明显的协同效应。     

Correlation Analysis between UCP2 Gene and Growth Traits in Ningxia Hibrid Simmental Cattle

To find genotype with fast growth rates in Ningxia hibrid Simmental cattle,the genetic variation of UCP2 gene were detected by PCR-SSCP method and DNA sequencing,then analyzed UCP2 gene polymorphism related with some growth traits.The results showed that there were three SNPs (T632C,A655G and A689C) in UCP2 gene exon 1,which divided into AA,BB and AB genotypes by PCR-SSCP method.Individuals with different genotypes in different months of age,body weight,body height, chest circumference and body length were AA > AB > BB.AA genotype in different age of body height and chest circumference were significantly different than BB genotype (P < 0.05;P < 0.01),and were no significant difference with AB genotype (P > 0.05).The results demonstrated that T632C locus had significant meaning for improving weight trait breeding of Ningxia hibrid Simmental cattle,AA genotype could be the breeding genotype.     

Genetic parameter estimates for growth traits and prolificacy in Raeini Cashmere goats

The main objectives of this study were to estimate genetic and phenotypic parameters for growth traits and prolificacy in the Raeini Cashmere goat. Traits included, birth weight (BWT), weaning weight (WWT), 6-month weight (6WT), 9-month weight (9WT), 12-month weight (12WT), average daily gain from birth to weaning (ADG1), average daily gain from weaning to 6WT (ADG2), average daily gain from 6WT to 12WT (ADG3), survival rate (SR), litter size at birth (LSB) and litter size at weaning (LSW) and total litter weight at birth (LWB). Data were collected over a period of 28 years (1982-2009) at the experimental breeding station of Raeini goat, southeast of Iran. Genetic parameters were estimated with univariate models using restricted maximum likelihood (REML) procedures. In addition to an animal model, sire and threshold models, using a logit link function, were used for analyses of SR. Age of dam, birth of type, sex and of kidding had significant influence (p < 0.05 or 0.01) all the traits. Direct heritability estimates were low for prolificacy traits (0.04 ± 0.01 for LSB, 0.09 ± 0.02 for LSW, 0.16 ± 0.02 for LWB and 0.05 ± 0.02 for SR) and average daily gain (0.12 ± 0.03 for ADG1, 0.08 ± 0.02 for ADG2, and 0.07 ± 0.03 for ADG3) to moderate for production traits (0.22 ± 0.02 for BWT, 0.25 ± 0.02 for WWT, 0.29 ± 0.04 for 6WT, 0.30 ± 0.02 for 9WT, 0.32 ± 0.05 for 12WT). The estimates for the maternal additive genetic variance ratios were lower than direct heritability for BWT (0.17 ± 0.03) and WWT (0.07 ± 0.02).     

胰岛素样生长因子-1基因多态性与猪部分生产性能的关系

采用PCR－RFLP对南昌白猪（92头）和大约克夏猪（170头）的IGF－1基因的179bp片段进行了扩增，并用HhaI酶切，产生两个等位基因A（151＋28bp)和等位基因B（116＋35＋28bp)。分析了不同基因型对个体初生重、2月龄重、4月龄重、6月龄重、料重比、背膘厚和瘦肉率等生产性能的影响。结果表明，在南昌白猪中，AA型猪比AB型猪初生重大，差异显著（P＜0.05)；在大约克夏猪中，BB型猪比AB型猪的6月龄体重大，差异显著（P＜0.05)；AA型猪比AB型和BB型猪瘦肉率低，差异极差著（P＜0.01)。     

宁夏西门塔尔杂种牛UCP2基因多态性及其与生长性状的关联性分析

本研究利用PCR-SSCP技术结合DNA测序确定UCP2基因SNP位点,检测其在宁夏西门塔尔杂种牛群体中的多态性,并分析其与生长性状的关联性。结果表明,UCP2基因第1外显子存在3个SNPs位点,分别为T632C、A655G和A689C,结合PCR-SSCP结果分析后,分为AA、BB、AB 3种基因型。不同月龄体高、体重、胸围、体斜长,总体呈AA>AB>BB。AA基因型个体在不同月龄体高、胸围显著或极显著高于BB基因型（P < 0.05;P < 0.01）,与AB基因型之间存在差异,但差异不显著（P > 0.05）。可以确定,T632C位点发生的碱基突变对宁夏西门塔尔杂种牛的体重性状选育存在显著意义,AA基因型个体可作为后期选育方向。     

Study on HMGA1 Gene Polymorphism Site and Its Association with Feed Efficiency Related Traits in Duroc Pigs

The objective of this study was to analyze two SNPs of HMGA1 gene,and investigate its association with feed efficiency related traits in Duroc populations.HMGA1 gene SNPs(g.-543 T > C and g.1356 C > T) in Large White pig and Min pig were detected by re-sequencing technology,SNP genotyping of g.-543 T > C and g.1356 C > T sites in Duroc populations were performed using Sequenom mass spectrometry,and the association of HMGA1 gene SNPs with growth and feed efficiency related traits in Duroc populations were analyzed.The results indicated that the individuals of CT genotype in g.-543 T>C increased 2.15 kg on 90 d body weight (P<0.05),decreased 3.21 d at 30 kg weight age (P<0.05),weaning weight was increased and 100 kg age were decreased,residual feed intake,30 to 100 kg average daily gain (ADG),40 to 90 kg average daily feed intake (ADFI) and 40 to 90 kg ADG were decreased,comparing with CC individuals.Moreover the individuals of CC genotype in g.1356 C>T had significantly increased 90 d body weight (0.37 kg,P<0.05),ADFI (less 0.13 kg,P<0.05),back fat (BF, less 0.43 mm,P<0.05),RFI (less 70.40 g,P<0.05),30 kg age (less 0.56 d,P<0.05) and 40 to 90 kg ADFI (less 0.17 kg,P<0.05) were significantly decreased;Weaning weight and 100 kg age were increased;30 to 100 kg ADG,40 to 90 kg ADG were decreased than TT genotype individuals.And the CT genotype individual in g.1356 C>T had the similar results with CC genotype individuals that compared with TT genotype individuals.All in all,the two SNPs of HMGA1 gene would be helpful in feed efficiency related traits in Duroc population.     

澳洲白绵羊美丽臀和肌肉生长抑制素基因基因型的检测

美丽臀(callipyge,CLPG)及肌肉生长抑制素(myostatin,MSTN)是全世界公认的与肌肉生长发育相关的基因,突变后分别产生“美丽臀”和“双肌”的优良性状。为研究国外进口品种澳洲白绵羊是否携带2种基因的突变位点,本试验以澳洲白绵羊为试验动物,采用PCR-RFLP技术对CLPG、MSTN基因的多态性进行分型。结果发现:CLPG基因上有1个C→T的SNP位点,澳洲白绵羊群体中有CC和CT 2种基因型;MSTN基因在3'-UTR区发现1个G→A的SNP位点,澳洲白绵羊群体中有GG和GA 2种基因型。用R语言程序对所测数据进行性别间不同基因型与生长发育状况的单因素方差分析得知,CLPG和MSTN基因不同基因型对澳洲白公羊体重、体高、体斜长、尻宽、背膘厚和眼肌面积均无显著性影响(P>0.05);CLPG基因CT基因型在母羊体重上显著高于CC基因型(P<0.05),在体斜长上极显著高于CC基因型(P<0.01),MSTN基因GA基因型母羊眼肌面积极显著高于GG基因型(P<0.01)。澳大利亚进口澳洲白绵羊中筛选到含有CLPG和MSTN基因的突变位点,且该突变位点对绵羊体尺性状有显著性作用,因此澳洲白绵羊引进后可以作为改良本地羊品种、基因聚合及三元配套系的终端父本。     

郏县红牛CLPG基因的SNP及对生长发育性状的影响

利用PCR-SSCP检测了113头郏县红牛CLPG基因的SNP，发现了AA、AB、AC 3种基因型，测序结果显示AA型在第150和419碱基处分别表现为C和T，为野生型；AB型在第419处发生碱基T→C突变；AC型在第150处发生碱基C→T突变。多态信息含量为0．226，属低度多态。分析了不同基因型与部分生长发育性状的相关性，结果显示，AA、AC基因型个体在体重、体长指标上显著（P〈0．05）或极显著（P〈0．01）大于AB型个体；在管围指标上，AA基因型个体优于AB基因型个体，差异显著（P〈0．05）；在坐骨端宽指标上，AA与AB基因型个体之间差异显著（P〈0．05），AB与AC基因型个体间差异极显著（P〈0．01）。     

The effect of a leptin single nucleotide polymorphism on quality grade, yield grade, and carcass weight of beef cattle

Feedlot producers could optimize the value of cattle in a given market grid if they were able to improve the uniformity of the body composition between cattle among loads. Allelic variation due to a single nucleotide transition (cytosine [C] to thymine [T] transition that results in a Arg25Cys) has been demonstrated to be associated with higher leptin mRNA levels in adipose tissue and increased fat deposition in mature beef, but the effect on economically important carcass traits has not been investigated in either market-ready steers or heifers. Therefore, the objective of this study was to determine the effects of a leptin SNP on the quality grade (QG), yield grade (YG), and weight of beef carcasses. A slaughter trial was conducted using 1,435 crossbred finished heifers and 142 crossbred finished steers as they entered the slaughter facility. Canada QG tended (main effect of genotype P = 0.16, but P < 0.01 for both CC vs. TT and CT vs. TT) to be affected by leptin genotype. Specifically, 7.6 and 7.1% more TT carcasses graded Canada AAA or higher than the CT and CC carcasses, respectively, which supports the suggestion that the leptin SNP is associated with carcass fat. The proportion of carcasses grading Canada YG 1, 2, or 3 was affected (P < 0.01, P = 0.05, and P = 0.02 for YG 1, 2, and 3) by leptin genotype. The proportion of TT carcasses of Canada YG 1 was 12.5 and 15.1% lower than that of CT and CC carcasses, respectively, indicating that rearing animals under the same management and feeding system may result in greater carcass fat and a lower probability of the proportion of carcasses grading YG 1 within certain genotypes. The carcass weights of animals with the CC genotype tended (P = 0.07) to be higher than those of the TT genotype (365.5 vs. 362.3 kg). No significant difference was observed between the TT and CT genotypes in carcass weight. The observed associations between leptin genotype and carcass characteristics may represent an opportunity to genetically identify animals that are most likely to reach specific marketing groups.     

绵羊CLPG和MSTN基因多态性及其与生长性状的关联分析

试验旨在探究CLPG(Callipyge)与MSTN(Myostatin)基因作为绵羊生长性状候选基因的可能性,调查与绵羊生长性状相关的分子遗传标记。本试验以133只澳洲白羊×杜泊羊×湖羊杂交绵羊为研究对象,利用PCR产物直接测序及PCR-RFLP技术检测CLPG与MSTN基因的单核苷酸多态性,然后通过SPSS22.0软件GLM统计模型分析多态位点不同基因型及聚合基因型与绵羊生长性状的关联性。测序结果表明,CLPG基因STS序列232bp处检测到C→T突变位点C1,MSTN基因3'UTR区检测到G→A突变位点M1。PCR-RFLP分析显示,C1位点表现为2种基因型:CC和CT;M1位点表现为2种基因型:GG和GA。关联分析表明,C1位点与绵羊背膘厚和眼肌面积显著或极显著相关(P<0.05;P<0.01),M1位点与绵羊体重、管围、背膘厚和眼肌面积显著或极显著相关(P<0.05;P<0.01)。聚合基因型对体重、背膘厚和眼肌面积影响极显著(P<0.01)。研究揭示CLPG与MSTN基因多态性及其聚合基因型对绵羊生长性状具有显著影响,C1和M1位点可以考虑作为绵羊生长性状的有效遗传标记。     

Polymorphism of CLPG and MSTN Genes and their Association Analysis with Growth Traits in Sheep

The study was conducted to explore the possibility that CLPG (Callipyge) and MSTN (Myostatin) genes which could be the candidate genes of sheep growth traits, and investigate the molecular genetic markers related to sheep growth traits.133 (Austrilian White sheep×Dorper sheep×Hu sheep) hybid-sheep were chosen as subjects, the technology of direct sequencing of PCR products and PCR-RFLP were used to detect the single nucleotide polymorphism of CLPG and MSTN genes, then the association of the SNPs different genotypes and combined genotypes with sheep growth traits were analyzed by the GLM statistical model of SPSS 22.0.Sequencing results showed that the SNP of C/T which called C1 was detected at position 232 bp of the STS sequence in CLPG gene.The SNP of G/A which called M1 was detected in the 3'UTR of MSTN gene.PCR-RFLP analysis showed that two genotypes CC and CT were in C1 site, two genotypes GG and GA were in M1 site.Association analysis revealed that C1 site was significantly or extremely significantly associated with backfat thickness and loin muscle area (P<0.05;P<0.01), M1 site was significantly or extremely significantly associated with body weight, tube girth, backfat thickness and loin muscle area (P<0.05;P<0.01).Meanwhile, the combined genotype was extremely significantly associated with body weight, backfat thickness and loin muscle area (P<0.01).The conclusions indicated that SNPs and combined genotype of CLPG and MSTN genes had effects on growth traits in sheep.C1 and M1 sites could be considered as effective genetic markers for sheep growth traits.