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1.
本试验采用单核苷酸多态性(single nucleotide polymorphism,SNP)直接测序法检测猪锚蛋白重复序列和SOCS盒蛋白基因4(ankyrin repeat and SOCS box containing protein 4,Asb4)与生长因子受体结合蛋白基因10(growth factor receptor-bound protein 10,Grb10)在不同组织器官中的印迹状态。首先,克隆得到了1350 bp的Asb4基因cDNA序列及1811 bp的Grb10基因cDNA序列,然后进行了SNP直接测序法检测。结果发现,Asb4在1月龄仔猪所有检测组织器官中均为双等位基因表达,而Grb10在1月龄仔猪的舌、肾脏、胃、小肠和脑中为父源等位基因表达,在其他组织器官中为双等位基因表达。实时定量PCR结果表明,Grb10在10种组织器官中的表达量存在显著性差异(P<0.05),其中在肺脏组织中的表达量最高,在小肠和脑中表达量最低。上述结果表明,Grb10可能是猪父源表达的印迹基因,而Asb4则属于猪非印迹基因。  相似文献   

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基因组印记是一种表观调控机制,在哺乳动物的发育中具有重要作用。印记基因是仅一方亲本来源的同源基因表达,而来自另一亲本不表达的一种基因。近年来,印记基因被广泛研究。印记基因分为父系印记基因和母系印记基因,其表达具有组织特异性,而且在胚胎不同发育阶段的表达也具有一定差异,胚胎期的营养水平也影响印记基因的表达。DNA甲基化在调控印记基因的表达中起重要作用,影响细胞核移植过程细胞的表观重编程,并影响胎盘及内脏器官的正常发育;基因印记模式的改变也可以引起甲基化的改变进而导致基因印记的丢失等。本文综述了近年来关于牛的印记基因的研究进展情况,为印记基因的后续相关研究工作提供借鉴。  相似文献   

4.
Variances caused by the differential expression of paternally and maternally imprinted genes controlling carcass traits in Japanese Black cattle were estimated in this study. Data on marbling score (BMS), carcass weight, rib thickness, rib‐eye area (REA) and subcutaneous fat thickness (SFT) were collected from a total of 13,115 feedlot steers and heifers in a commercial population. A sire–maternal grandsire model was used to analyse the data, and then, imprinting parameters were derived by replacing the genetic effect of the dam with the effect of the maternal grandsire in the imprinting model to calculate the genetic parameter estimates. The proportions of the total genetic variance attributable to imprinted genes ranged from 8.7% (SFT) to 35.2% (BMS). The remarkably large imprinting variance of BMS was mainly contributed by maternally expressed inheritance because the maternal contribution of the trait was much larger than that of the paternal trait. The parent‐of‐origin effect originating from maternal gene expression was also observed for REA. The results suggested the existence of genomic imprinting effects on the traits of the Japanese Black cattle. Hence, the parent‐of‐origin effect should be considered for the genetic evaluation of Japanese Black cattle in breeding programmes.  相似文献   

5.
Genomic imprinting confers allele-specific expression in less than 1% of genes, in a parent-of-origin specific fashion. In humans and mice the Peg1/Mest gene (Mest) is maternally repressed, and paternally expressed. Mest is expressed in embryogenic mesoderm-derived tissues and in adult brain, and paternal mutations in Mest lead to growth retardation and defective maternal behaviour. Despite our current understanding of mechanisms associated with the establishment of imprinting of Mest and other imprinted genes, it is unclear to what extent Mest imprinting needs to be maintained in adult tissues. Aberrations of imprinting are known to occur in certain rare syndromes, and involve either inherited mutations, or constitutive epigenetic alterations occurring soon after fertilization. Imprinting abnormalities may also occur in the aging somatic tissues of adult individuals. Here we report an occurrence of post-embryonic somatic variability of Mest allelic expression in a colony of mice where heterozygotes at the imprinted Mest locus for a mutation inherited from the father spontaneously expressed the normally silenced allele from the mother. In addition, a newly acquired ability to overcome the deficit in maternal reproductive behaviour had occurred in the mutant mice, but this appeared not to be directly linked to the Mest mutation. Our results suggest that at least one allele of Mest expression is required in the somatic tissues of adult individuals and that under certain conditions (such as in the presence of a Mest insertional mutation or in an altered genetic background), somatically acquired alterations of allelic expression at the Mest locus may occur.  相似文献   

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Imprinted genes display biased expression of paternal and maternal alleles in mammals. They are marked through epigenetic process during gametogenesis. Characterization of imprinted genes has expanded our understanding of the regulation and function of genes. In the current study, 22 experimentally validated imprinted genes in bovine (Bos Taurus) were analysed. Several supervised machine learning algorithms and attribute weighting methods were used to find characteristics of different types of imprinted genes and suggest a classification method for finding maternally and paternally expressed genes in bovine. For assessing the best model and comparing attributes in other organisms, we have also conducted a comparative analysis for human and sheep imprinted genes. According to the results of the present study, GC contents 10 and 100 kb upstream, Gly and Gln amino acids, Ile/ATC codon usage, LINE and SINE in 100kbup and length of first intron were significantly different between the maternal and paternal genes in cattle. Considering all species together, we found that GC content 100 kb up, LINE 100 kb up and the frequency of amino acids like Gly, Gln and Met were the most important attributes for identifying the paternal and maternal imprinted genes. These findings could imply conservation pattern in the attributes among these species.  相似文献   

7.
DDRT-PCR技术用于寻找小鼠印迹基因的原理,主要通过观察小鼠亲本及它们杂交后代等位基因的多态表达,就能清楚区分基因的母源表达与父源表达,从而筛选出印迹基因。本研究通过DDRT-PCR技术克隆到了一个新的印迹基因,并对其染色体定位,基因结构和表达等特性进行了初步研究。  相似文献   

8.
Primordial germ cells (PGCs) from day 27 porcine fetuses have often been isolated to establish pluripotent embryonic germ (EG) cell lines, but little is known regarding their imprinted gene status. In our study, we attempted to detect the imprinted gene expression of cloned embryos and EG cells derived from individual PGC of day 27 and day 35, using single nucleotide polymorphism (SNP) analysis of the paternally expression gene 10 (PEG10) as a sign of parental‐origin‐specific expression. The results showed biallelic gene expression of the SNP that occurred in EG cell colonies and almost all of the cloned blastocysts, demonstrating that aberrant imprinted gene expression of PEG10 occurs in the day 27 porcine PGCs, whereas monoallelic expression of the PEG10 gene occurs in all the PGC clones derived from day 35 PGCs. In addition, the same imprinted gene status was observed for blastocysts derived from both male and female PGCs, indicating that the parental genomic imprinting is erased in male and female germlines.  相似文献   

9.
DNA甲基化调控牛AQP1基因的胎盘特异性印记   总被引:1,自引:1,他引:0  
为揭示牛AQP1(aquaporin 1)基因在不同组织及胎盘中的印记状态,以及DNA甲基化修饰在印记中的调控机制,本研究采用基于SNP的PCR产物直接测序的方法,对32头健康雌性成年荷斯坦奶牛心组织及15个自然分娩后的胎盘试验样本进行检测,确定了5头杂合子个体牛和3个杂合子胎盘,对其组织(心、肝、脾、肺、肾、肌肉和脂肪)和胎盘进行AQP1等位基因表达分析及印记状态分析,利用亚硫酸氢盐测序法分析AQP1基因位于启动子和第一个外显子区的CpG岛在牛心、肝组织、2个胎盘和对应精子中的DNA甲基化状态。结果发现,在杂合子牛被检测的7个组织中,AQP1基因呈现双等位基因表达;而在胎盘中,AQP1基因为单等位基因表达。通过分析杂合子胎盘对应的亲本基因型,发现AQP1基因为母源等位基因表达,即父源印记。进一步比较分析AQP1基因启动子区CpG岛在牛组织、胎盘及对应精子中的甲基化状态,在双等位基因表达的心脏、肝脏组织中,该区域未发现差异甲基化区(differentially methylated regions,DMR);而在单等位基因表达的胎盘中,存在差异甲基化区,同时父源等位基因精子中为重甲基化状态。以上结果说明,牛AQP1基因为胎盘特异性单等位基因表达的父源印记基因,且AQP1基因位于启动子和第一个外显子区的CpG岛甲基化修饰参与调控牛胎盘的印记表达;在被检测的组织中为双等位基因表达。  相似文献   

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CD81和CCL26基因是影响哺乳动物性腺细胞融合的重要因子,但其在黔北麻羊性腺组织中的表达情况尚不清楚。为研究CD81和CCL26基因在黔北麻羊不同组织中的表达量,本实验以单、多羔黔北麻羊为研究对象,提取下丘脑、垂体、子宫、输卵管、卵巢组织的RNA,并将5种性腺组织RNA逆转录合成第一链cDNA,随后采用q-PCR技术检测CD81、CCL26基因的mRNA在单、多羔黔北麻羊不同性腺组织中的表达水平。结果表明:黔北麻羊性腺组织中CD81、CCL26基因的mRNA均有表达,2种基因均在单、多羔卵巢中的表达量最高;CD81基因在单羔组子宫中的表达量最低;CD81基因在多羔组、CCL26基因在单多羔组下丘脑中的表达量均最低;组间差异表达量分析可知,CD81基因在多羔组子宫的表达量显著高于单羔组;CCL26基因在单羔组卵巢和输卵管的表达量显著高于多羔组,在单羔组子宫的表达量极显著高于多羔组。本实验结果提示,CD81和CCL26基因可能与山羊繁殖能力相关,也为初步揭示山羊繁殖的分子调控机制提供了参考依据。  相似文献   

12.
Genetic variances due to imprinted genes in cattle   总被引:1,自引:0,他引:1  
The effect of paternally expressed, i.e. maternally imprinted, genes on slaughter records from 2744 German Gelbvieh finishing bulls were estimated. Significant effects of paternal gametes were found for two fatness traits and an estimate of meat content. Paternally expressed genes explained 14 and 16% of the phenotypic variances for pelvic fat and kidney fat, respectively. Ignoring paternal gametic effects resulted in inflated estimates of the additive genetic variances. The heritabilities of pelvic and kidney fat dropped from 0.31 to 0.16 and from 0.59 to 0.28, respectively, when paternal gametes were fitted. A 15% influence of paternally expressed genes and a reduction in heritability of 20% were also found for estimated meat content. Simulation studies demonstrated that the uncorrelated random effect of the sire is a useful indicator for the presence of paternal gametic effects in variance component estimations. The presented results correspond well with findings in swine, where a paternally expressed QTL at the Igf2 gene influences similar trait complexes. A viable speculation could therefore be that an imprinted bovine Igf2 gene caused the effects described here.  相似文献   

13.
Traditional genetic selection in cattle for traits with low heritability, such as reproduction, has had very little success. With the addition of DNA technologies to the genetic selection toolbox for livestock, the opportunity may exist to improve reproductive efficiency more rapidly in cattle. The US Meat Animal Research Center Production Efficiency Population has 9,186 twinning and 29,571 ovulation rate records for multiple generations of animals, but a significant number of these animals do not have tissue samples available for DNA genotyping. The objectives of this study were to confirm QTL for twinning and ovulation rate previously found on BTA5 and to evaluate the ability of GenoProb to predict genotypic information in a pedigree containing 16,035 animals when using genotypes for 24 SNP from 3 data sets containing 48, 724, or 2,900 animals. Marker data for 21 microsatellites on BTA5 with 297 to 3,395 animals per marker were used in conjunction with each data set of genotyped animals. Genotypic probabilities for females were used to calculate independent variables for regressions of additive, dominance, and imprinting effects. Genotypic regressions were fitted as fixed effects in a 2-trait mixed model analysis by using multiple-trait derivative-free REML. Each SNP was analyzed individually, followed by backward selection fitting all individually significant SNP simultaneously and then removing the least significant SNP until only significant SNP were left. Five significant SNP associations were detected for twinning rate and 3 were detected for ovulation rate. Two of these SNP, 1 for each trait, were significant for imprinting. Additional modeling of paternal and maternal allelic effects confirmed the initial results of imprinting done by contrasting heterozygotes. These results are supported by comparative mapping of mouse and human imprinted genes to this region of bovine chromosome 5.  相似文献   

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The fundamental assumption of Mendelian genetics is that behavior of an allele is identical whether it arrives to a zygote through paternal or maternal germline pathway. Gametic imprinting phenomena discovered and studied in mammals show limitations of the classical view in special cases. Two sources of evidence were essential to describe gametic imprinting. The first approach based on genetic evidence demonstrated that some maternally and paternally derived regions of certain chromosomes were not equivalent. Paternal or maternal disomy of the regions containing particular genes caused significant effects on viability and development of progeny. The second set of data was obtained by nuclear transplantations and parthenogenetic activation of mammalian oocytes. These data suggested that the contribution of parental genomes was not equivalent and differential imprinting of nuclear genes during gametogenesis was very likely. The number of loci found in mice, which show gametic imprinting, is 34 and continues to grow. It is generally accepted that gametic imprinting is a mammalian invention and there are differences in imprinting pattern between species. Most hypotheses propose involvement of imprinted genes in the control of fetal growth and fetal-maternal interactions, thus keeping a balance between contradictory fetal and maternal requirements. Molecular mechanisms responsible for gametic imprinting still remain to be studied, but for several genes it was shown that imprinting marks are imposed by a parent-specific methylation process during gametogenesis. These marks are resistant to global demethylation during cleavage and to global de novo methylation after implantation and maintain different methylation patterns in paternal and maternal alleles of imprinted genes. About 20 to 25% of all transgene loci studied demonstrate similarities with imprinted genes. For instance, methylation of some transgenes is dependent on parental gametic pathway and reversible in the next generation. There are data indicating that selection of modifier genes may change the effects of gametic imprinting. It is possible that future selection and crossbreeding programs may take gametic imprinting into consideration.  相似文献   

15.
基因组印记的研究进展   总被引:3,自引:0,他引:3  
综述基因组印记的可能发生机制及人和鼠中常见的印记基因,论述了且印记作用的生物学意义。  相似文献   

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本研究旨在对草原红牛AIDA基因进行克隆、生物信息学分析和差异表达研究,并构建真核表达载体,以期在细胞水平上探究AIDA基因对牛前体脂肪细胞分化的影响。应用RT-PCR方法从草原红牛脂肪组织中扩增AIDA基因编码区,测序鉴定后对其核苷酸和氨基酸序列进行生物信息学分析,同时利用实时荧光定量PCR技术研究AIDA基因在草原红牛9个组织(心脏、肝脏、脾脏、肺脏、肾脏、胃、肠、肌肉、脂肪)和前体脂肪细胞成脂分化过程中的表达规律;构建真核表达载体pBI-CMV3-AIDA,转染草原红牛前体脂肪细胞,通过实时荧光定量PCR方法检测AIDA基因在mRNA水平上的表达情况。结果显示,AIDA基因编码区全长921 bp,编码306个氨基酸,含有4个潜在的糖基化位点和29个潜在的磷酸化位点;亚细胞定位主要分布于细胞质、细胞核和线粒体上。AIDA基因在草原红牛9个组织中均有表达,其中在肾脏组织中表达量最高,显著高于其他组织(P<0.05)。成脂分化结果表明,AIDA基因mRNA表达量在分化的第2天达到最高,随着脂肪细胞的成熟,其表达量逐渐降低;双酶切及测序结果表明,试验成功构建了AIDA基因的真核表达载体pBI-CMV3-AIDA,且过表达组AIDA基因mRNA表达量极显著高于对照组(P<0.01)。本试验成功构建了AIDA基因真核表达载体,并在草原红牛前体脂肪细胞中高度表达,该结果为体外研究牛AIDA基因对脂肪合成代谢及其机体代谢的调节机制提供了基础材料。  相似文献   

17.
We studied the longevity of mice produced without sperm using the genomes of oocytes that are already committed to a germline cell lineage. The first sperm-free mouse "KAGUYA", which we term 'bi-maternal mouse', was born on 3 February, 2003. Bi-maternal embryos were generated using 2 sets of female genomes--one derived from fully grown oocytes from normal adults and the other from non-growing oocytes from newborn pups. These genomes were combined by nuclear transfer. We refined the technique for generating bi-maternal mice and found that genetic manipulations in only 2 regions--the imprinting centres of Igf2-H19 and Dlk1-Gtl2--on chromosomes 7 and 12 of the newborn pups allowed us to generate bi-maternal mice at a high rate. Studying bi-maternal conceptuses and mice provides further insight into the mechanisms by which paternally methylated imprinted genes regulate mammalian ontogenesis.  相似文献   

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为了探究CD46基因在新疆褐牛不同组织中的表达丰度差异,初步掌握CD46基因在新疆褐牛不同组织中的表达规律,试验设计了特异性引物,应用实时荧光定量PCR技术分析新疆褐牛心脏、肝脏、脾脏、肺脏、肾脏、小肠、大肠、胃、肌肉、卵巢和乳腺中的CD46基因表达情况。结果表明,新疆褐牛CD46基因在所检测的11种组织中均有表达,不同组织部位的表达存在差异,其中肝脏CD46表达丰度最高,其表达丰度显著高于肺脏、脾脏、肾脏、胃、小肠、大肠、卵巢和乳腺(P< 0.05)。本研究对新疆褐牛各组织CD46基因的表达规律进行初步分析,为CD46基因表达规律与其生物功能研究的开展提供了参考依据。  相似文献   

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Findings within the last 15 years emphasize the possible role of genomic imprinting for trait expression in livestock species. In genetic evaluation, genomically imprinted traits can be treated by models with two different breeding values per animal; one accounts for the paternal and the other for the maternal expression pattern. Relative weighting factors for these breeding values were derived by a generalized version of the discounted gene flow method, which was extended to a gametic level to account for parent‐of‐origin effects. The gametic approach proved also useful for calculating the expected increase in inbreeding induced by one round of selection and its dynamics over time. The gametic gene flow method was applied to a hypothetical pig breeding programme. Relative weighting factors were higher for the paternally inherited genetic effect even in female selection paths, but depend on the breeding scheme heavily. The maximum medium‐term increase in inbreeding due to selection exceeded the long‐term increase in a range of 20–100%.  相似文献   

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