干旱区生态环境知识资源中心

Garole sheep of West Bengal (India) is known to carry mutation in an autosomal gene FecB (Booroola allele or FecB(B)) on ovine chromosome 6. The mutation is known to affect ovulation rate and in turn litter size in Garole sheep. The mutated allele is hypothesized to be the original genotype of the breed and by this virtue the sheep produces twins, triplets and quadruplets. To incorporate the character of higher prolificacy in mutton type non-prolific Malpura sheep of semi-arid region of Rajasthan, Garole sheep was used as sire breed in FecB introgression programme started in 1997 at this institute. Presence of FecB allele was detected in Garole and Garole x Malpura (GM) sheep. The genotypic frequencies for homozygous carriers (FecB(BB)) were 0.86 and 0.06 in Garole and GM, respectively. The corresponding figures for heterozygous carriers (FecB(B+)) were 0.13 and 0.71, respectively. In Garole x Malpura crosses the FecB gene in F, generation is present in heterozygous state and segregate in homozygous state in F, and F 3 generation.