Abstract:

【Objective】 The present study was performed to investigate the relationships between the mRNA level of BMP2, BMP4, BMP6 and BMP7 gene in ovaries and the ovulation number in Hu sheep, so as to provide references for finding hyper- prolificacy candidate gene and understanding the molecular genetic mechanism of high fecundity in Hu sheep. 【Method】 Sixteen adult Hu ewes, classified as the single lambling (S) or multiple lambling (M) group, were sacrificed for tissue sampling and ovulation number counting between 24-36h after estrus diagnosis. The tissue distributions of BMP2, BMP4, BMP6 and BMP7 mRNA were detected by RT-PCR and the gene expression levels in the ovaries were investigated by real-time PCR. 【Result】 BMP2, BMP4 and BMP7 mRNA exited in the ovary and other tissues, including hypothalamus, pituitary, uterus, heart, liver, spleen, lung, kidney, muscle and oviduct, but BMP6 mRNA was only detected in the ovary, kidney, muscle and oviduct. The expression level of BMP2, BMP6 and BMP7 mRNA in the ovary did not differ between S and M group (P＞0.05), but BMP4 mRNA abundance in the ovary was extremely higher in M group than that in S group (P＜0.01). Bivariate correlation analysis showed that BMP4 mRNA expression in the ovary was positively correlated with ovulation number (r = 0.741, P＜0.05), but there was no correlation between the mRNA expression level of BMP2, BMP6 or BMP7 and the ovulation number (P＞0.05). 【Conclusion】 The results suggested that BMP4 might play a key role in ovulation number and might be a candidate gene for high fecundity in Hu sheep.

Key words: hu sheep, ovulation number, BMP2, BMP4, BMP6, BMP7, mRNA expression