Cloning and Polymorphisms of 1^st-7^th Exons in FSHR of Jinding Ducks

Animal reproductive activities are largely regulated by reproductive endocrine hormones. The follicle stimulating hormone receptor (FSHR) is found in the follicular granulose membrane of an ovary cell in a female animal. It is a G protein coupled receptor that plays an important role in the development, maturation and ovulation of the ovary cells. Considering its critical association with poultry broodiness, FSHRs from high-and low-egg-laying Jinding ducks were compared. The fragments at the lengths of 330 bp (Fragment a), 700 bp (Fragment b), 310 bp (Fragment c), 366 bp (Fragment d) and 540 bp (Fragment e) of the genes from the genomic DNAs extracted from the blood samples of the ducks were amplified by PCR. The sequence analysis showed that Fragment a included the entire sequence of the 1^st exon (185 bp), as well as a partial sequence of the 1^st intron (145 bp) of the gene; Fragment b had the complete sequences of the 2^nd intron (463 bp), the 2^nd exon (75 bp) and the 3^rd exon (75 bp), in addition to the partial sequences of the 1^st intron (40 bp) and the 3^rd intron (47 bp); Fragment c consisted of the sequence of the 4^th exon (75 bp), as well as the partial sequences of the 3^rd intron (180 bp) and the 4^th intron (55 bp); Fragment d included the sequence of the 5^th exon (78 bp), and the partial sequences of the 4^th intron (232 bp) and the 5^th intron (56 bp); and, Fragment e contained the entire sequences of the 6^th exon (69 bp), the 7^th exon (75 bp) and the 6^th intron (117 bp), also the partial sequences of the 5^th intron (133 bp) and the 7^th intron (146 bp). By comparison, it was found that the 1^st exon had an A/G mutation at position 50 bp; the 2^nd exon, an A/G mutation at position 30 bp; the 4^th exon, a C/T mutation at position 33 bp; and, the 5^th exon, an A/G mutation at position 45 bp, an A/T mutation at 19 bp, as well as a C/T mutation at 33 bp. The results obtained would pave the way for further study on the FSHR polymorphism and egg-laying performance of Jinding ducks.