Abstract: As gonadotropin-releasing hormone 1 (GnRH1) is the main form of GnRH present in the pituitary, it seems apparent that it is responsible for regulating the reproductive endocrine system to stimulate gonadotropins. The GnRH1 gene was studied as a candidate gene for high prolificacy in some goat breeds (Capra hircus). Single nucleotide polymorphisms (SNPs) of three exons (exons 2, 3 and 4) of GnRH1 gene were detected in high prolificacy breed (Jining Grey goat), moderate prolificacy breed (Boer goat) and low prolificacy breeds (Inner Mongolia Cashmere and Angora goats) by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). No polymorphism was detected in the amplified region in the four goat breeds tested. DNA fragments of exons 2, 3 and 4 of Jining Grey goat GnRH1 gene were cloned into pSRUE-T vector. The positive clones were further identified by PCR. The nucleotide sequences were detected and the amino acid sequences of these three fragments were deduced. The comparison of the fragments of all three coding regions of Jining Grey goat GnRH1 gene with those of cattle， human, dog, chimpanzee, monkey, rat and mouse GnRH1 gene showed that the homologies of the nucleotide sequences and amino acid sequences of the fragments among these eight species were from 73.6% to 99.3% and from 62.0% to 97.8% respectively. The results indicated that the exons 2, 3 and 4 of GnRH1 gene were highly conserved among mammals, and may not be the functional domains that affect the high prolificacy in goats.

Key words: goat; gonadotropin-releasing hormone 1 gene; PCR-SSCP