Abstract: To study the fecundity of Wadi sheep on molecular level,polymorphisms within the FecB gene of Wadi sheep and associations with litter size were analyzed by PCR-RFLP. The results showed that there was FecB mutation in Wadi sheep that was the same as in Booroola,and the frequencies of three genotypes (B/B,B/+,+/+) were 0.29,0.56 and 0.15,respectively. An association between genotype frequencies and number of nipples was observed. Average litter sizes for the three genotypes were 2.81±0.42,2.49±0.53 and 1.96±0.28,respectively. Statistical analysis showed that litter size of Wadi sheep with B/B and B/+ genotypes were significantly greater than that of sheep with the +/+ genotypes (P＜0.05),but differences between the B/B and B/+ genotypes were not significant(P＞0.05). These results indicated that the FecB gene could be of great interest in the Wadi sheep breed due to its association with fecundity.

Key words: Wadi sheep; FecB gene; polymorphism; litter size