RESUMO
Several previous studies have investigated whether the -160C/A epithelial cadherin promoter polymorphism confers an increased risk of diffuse gastric cancer (DGC), but conflicting results have been reported. To explore further the association of this polymorphism with DGC susceptibility, we performed an extensive search of relevant studies and conducted a meta-analysis to obtain a more precise estimate. We conducted a systematic literature search using the databases EMBASE, PubMed, and Web of Knowledge for reports published before August 2012 that met certain criteria. Information was carefully and independently extracted from all eligible publications by 2 of the authors. Twelve distinct data sets from 10 case-control studies were analyzed. They included 1115 cases of DGC and 2965 controls. Although none of the genotypes was associated with DGC risk, a slight trend of increased risk was found among A allele carriers [odds ratio (OR) = 1.237, 95% confidence interval (95%CI), 0.940-1.627], CA heterozygotes (OR = 1.229, 95%CI = 0.938-1.610), and AA homozygotes (OR = 1.146, 95%CI = 0.684-1.918). However, when the cases were stratified by ethnicity, a diverging trend occurred in AA homozygotes between the Asian group (OR = 0.710, 95%CI = 0.328-1.536) and its Caucasian counterpart (OR = 1.434, 95%CI = 0.657-3.131). Taken together, the summarized analyses of these case-control studies demonstrated that the -160A of the epithelial cadherin gene exhibited no significant association with susceptibility for DGC; however, the results suggested that it is a potential genetic risk factor in both Asians and Caucasians. Additional large-scale, well-designed studies are necessary to confirm whether AA homozygosity is a protective factor in Asians.
Assuntos
Caderinas/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Neoplasias Gástricas/genética , Alelos , Povo Asiático/genética , Genótipo , Humanos , Polimorfismo de Nucleotídeo Único , Fatores de RiscoRESUMO
We investigated the polymorphisms of PRLR and FOLR1 genes in Xinong Saanen, Guanzhong, and Boer goat breeds by DNA sequencing and PCR-RFLP. Two novel SNPs were identified: KC109741: g.62130C>T in the 3ê-UTR of goat gene PRLR, and KC136296: g.7884A>C in exon 3 of goat gene FOLR1. In the three goat breeds, the polymorphism information content was 0.20-0.27 at the g.62130C>T locus. At the g.7884A>C locus, it was 0.36 in Boer goats. The three goat breeds were in Hardy-Weinberg disequilibrium at the g.62130C>T locus. The g.62130C>T SNP was found to be significantly associated with milk production traits in Xinong Saanen and Guanzhong breeds. These results are consistent with the regulatory function of PRLR in mammary gland development, milk secretion, and expression of milk protein genes; they extend the spectrum of genetic variation of the goat PRLR gene, which could be useful for breeding programs.
Assuntos
Receptor 1 de Folato/genética , Estudos de Associação Genética , Leite , Receptores da Prolactina/genética , Regiões 3' não Traduzidas , Animais , Cruzamento , Genótipo , Cabras/genética , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNARESUMO
Kisspeptins, the product of the KISS1 gene, play an essential role in the regulation of reproductive functions, acting primarily at the hypothalamic level of the gonadotropic axis. We detected polymorphisms of the goat KISS1 gene in 723 individuals from three goat breeds (Xinong Saanen, Guanzhong, and Boer) by DNA pooling, PCR-RFLP, and DNA sequencing methods. We cloned the promoter sequence of this gene and found it to share high similarity with that of the bovine KISS1 promoter. Six TATA boxes were found in the goat KISS1 promoter region. Two novel SNPs (g.2124T>A and g.2270C>T) were identified in the intron 1 of the KISS1 gene of all three goat breeds. The three goat breeds were in Hardy-Weinberg disequilibrium at g.2124T>A and g.2270C>T loci. The g.2124T>A and g.2270C>T loci were closely linked in the three goat breeds (r2 > 0.33). The g.2124T>A and g.2270C>T SNPs were significantly associated with litter size, and the C1 female goats had a larger litter size than did those with the other genotypes. These results extend the spectrum of genetic variation of the goat KISS1 gene, which contributes to our knowledge of goat genetic resources for breeding programs.
Assuntos
Cabras/genética , Kisspeptinas/genética , Tamanho da Ninhada de Vivíparos/genética , Polimorfismo de Nucleotídeo Único , Regiões Promotoras Genéticas , Animais , Clonagem Molecular , Feminino , Frequência do Gene , Estudos de Associação Genética , Loci Gênicos , Genótipo , Desequilíbrio de Ligação , Mutação Puntual , Polimorfismo de Fragmento de Restrição , Análise de Sequência de DNARESUMO
Complementary DNA (cDNA) is valuable for investigating protein structure and function in the study of life science, but it is difficult to obtain by traditional reverse transcription. We employed a novel strategy to clone human leukemia inhibitory factor (hLIF) gene cDNA from genomic DNA, which was directly isolated from the mucous membrane of mouth. The hLIF sequence, which is 609 bp long and is composed of three exons, can be acquired within a few hours by amplifying each exon and splicing all of them using overlap-PCR. This new approach developed is simple, time- and cost-effective, without RNA preparation or cDNA synthesis, and is not limited to the specific tissues for a particular gene and the expression level of the gene.