Cloning, Expression And Function Of Duck Adiponectin And Its Receptor Genes

In this experiment, eight duck breeds (such as Kunshan Sheldrake, Cherry Valley Meat duck, Gaoyou duck, Shanma duck, Jinding duck, Longbai duck, Jingjiang Sheldrake and White feather Muscovy duck) were used, the objectives in this study were to cloning adiponectin and its receptor genes and investigating the expression of these genes in various tissues and organs, applying PCR-SSCP methods to detect their DNA polymorphism and evaluate association between polymorphism of adiponectin gene and growth and development of body fat traits. The main results are follows:(1) The DNA sequence of duck adiponectin and cDNA sequence of duck AdipoR were firstly reported. The homological comparison analysis among duck, chicken and mammal indicated the high identities both in adiponectin and AdipoR gene. The results indicated that these genes were conservative in the process of evolution and had important physiological function for the growth and development of birds and mammal.(2) The semi-quantity PCR revealed duck adiponectin, AdipoR1 and AdipoR2 mRNA expressed in all tissues. Adiponectin gene has high expression level in adipose, muscular stomach, small intestine, heart and skeletal muscle; and middle level in lung, glandular stomach, ovary and spleen; and weak level in liver, kidney and diencephalons. AdipoR1 gene has high expression level in spleen, adipose and lung; and middle level in heart, glandular stomach, muscular stomach and ovary; and weak level in liver, skeletal muscle, small intestine, diencephalons and kidney. AdipoR2 gene has high expression level in adipose and lung, and middle level in others.(3) In this experiment, five pairs of primers were designed based on sequence of open reading frame (ORF) of adiponectin gene, and then single nucleotide polymorphisms (SNPs) were detected by the technique of single strand conformation polymorphism (SSCP) and genetic polymorphism among different breeds was analyzed. Seven nucleotide variations including G430A,A457G,T523C,C507T, T540C, C576T and C597T were found, and the first three variations resulted in the amino acid variations including A144T, I153V, and Y175H, respectively. Eight genotypes (AA, AB, AC, BB, BC, CC, DD and DE) were detected in the 8 breeds. The result of X2 analysis showed that the distribution of eight genotypes was very different among different breeds (P<0.01). Except Jingding duck, other duck breeds followed Hardy-Weinbergs′equilibrium law. Genetic analysis indicated that the homozygosity index was highest in Jinding duck, lowest in Gaoyou duck and it was similar in other breeds. Jindings′PIC was of low level, Gaoyous′PIC was high level and others′duck breeds PIC were at the middle level.(4) The results of variance analysis showed that the Kunshan ducks of AA genotype had a higher sebum weight and sebum rate than the Kunshan ducks of AC genotype; the Cherry Valley meat ducks of BC genotype had a higher sebum rate, weight and rate of abdominal fat than those of AC and CC genotypes. It implied that adiponectin gene could be a candidate locus or linked to a major gene to significantly affect abdominal fat traits in duck.