RESUMO
This study aimed to screen single nucleotide polymorphisms (SNPs) in the chicken gap junction protein alpha 1 (GJA1) gene, and to investigate their association with five growth traits measured in 269 chickens encompassing Chinese indigenous Beijing-You (BJY) and commercial Cobb broiler (CB) populations. Four variants were detected in the chicken GJA1 gene, in which one synonymous mutation was located in an exon (C61223231T or c.-1110 C>T), two in an intron (A61229799C or c.5460 A>C, T61229928A or c.5589 T>A) and one in the promoter (A61230599C or c. 6260 A>C) regions. Genotyping was performed by high-resolution melting analysis (SNP in an exon) and DNA sequencing (SNP in the introns and promoter). Association analysis revealed that each SNP had a significant effect on growth traits in chicken. A higher level of genetic diversity was observed in the indigenous BJY breed than in the commercial CB breed. Strong linkage disequilibrium was observed between the C61223231T and A61229799C polymorphisms, and four previously undiscovered haplotypes (CA, TC, CC, TA) were constructed from those two mutations. Association analysis between haplotype combinations (diplotypes) and growth traits was highly significant where diplotype CC + CC was dominant for all traits. We speculated that GJA1 either is a major gene, or is associated with a major gene, affecting chicken growth traits. Therefore, further studies are needed in large populations to evaluate polymorphisms located in different regions of this gene, as well as its functional study, to better understand its role in muscle development in chicken.
Assuntos
Peso Corporal/genética , Galinhas/genética , Conexina 43/genética , Músculo Esquelético/metabolismo , Polimorfismo de Nucleotídeo Único , Característica Quantitativa Herdável , Animais , Cruzamento , Galinhas/crescimento & desenvolvimento , Galinhas/metabolismo , Éxons , Feminino , Expressão Gênica , Estudos de Associação Genética , Técnicas de Genotipagem , Haplótipos , Íntrons , Desequilíbrio de Ligação , Masculino , Músculo Esquelético/crescimento & desenvolvimento , Fenótipo , Regiões Promotoras Genéticas , Análise de Sequência de DNARESUMO
Growth hormone (GH) has diverse functions in animals, together with other hormones from the somatotropic axis. Here, chicken GH (cGH) was investigated in recessive white chickens and Qingyuan partridge chickens as a candidate gene affecting egg production traits. Chicken egg production traits were studied in association with 4 selected single nucleotide polymorphisms (T185G, G662A, T3094C, and C3199T). Genotyping was performed by the polymerase chain reaction-ligase detection reaction method. T185G was significantly associated with the egg production traits of body weight at first egg (BW), egg weight at first egg (EW), and the total egg production of 300-day old birds (EN 300). T3094C was also significantly associated with certain egg production traits; however, it affected the 2 breeds differently. Haplotypes of the 4 single nucleotide polymorphisms were also significantly associated with egg production traits of chicken age at first egg laying, BW, EW, and EN 300. H1H6 was the most advantageous diplotype for egg production. We putatively concluded that polymorphisms in the cGH gene and its haplotypes could be used as potential molecular markers for egg production traits to enhance the breeding programs of indigenous chickens.