DNA Tests in Prolific Sheep from Eight Countries Provide New Evidence on Origin of the Booroola (FecB) Mutation1

Abstract

Recent discoveries that high prolificacy in sheep carrying the Booroola gene (FecB) is the result of a mutation in the BMPIB receptor and high prolificacy in Inverdale sheep (FecX(I)) is the result of a mutation in the BMP15 oocyte-derived growth factor gene have allowed direct marker tests to be developed for FecB and FecX(I). These tests were carried out in seven strains of sheep (Javanese, Thoka, Woodlands, Olkuska, Lacaune, Belclare, and Cambridge) in which inheritance patterns have suggested the presence of major genes affecting prolificacy and in the prolific Garole sheep of India, which have been proposed as the ancestor of Australian Booroola Merinos. The FecB mutation was found in the Garole and Javanese sheep but not in Thoka, Woodlands, Olkuska, Lacaune, Belclare, and Cambridge sheep. None of the sheep tested had the FecX(I) mutation. These findings present strong evidence to support historical records that the Booroola gene was introduced into Australian flocks from Garole (Bengal) sheep in the late 18th century. It is unknown whether Javanese Thin-tailed sheep acquired the Booroola gene directly from Garole sheep from India or via Merinos from Australia. The DNA mutation test for FecB will enable breeding plans to be developed that allow the most effective use of this gene in Garole and Javanese Thin-tailed sheep and their crosses.

Application of PCR-RFLP technique to determine Booroola gene polymorphism in the Sangsari sheep breed of Iran

“…The results of the present research are in accordance with those obtained for Madras Red, Deccani, and Bunnur breeds (1)(2)(3)20,21). Research in India has shown that the Garol breed was the only breed carrying the FecB allele.…”

“…In fact, due to the long geographic distance between rearing environments for these 3 breeds, the mutant allele might have spontaneously occurred and subsequently been imported to Bunnur and Deccani crossbreds following breeding programs (1,3,20,21,26,27). Geographically, the Sangsari's natural breeding environment is located between Mazandaran and Isfahan provinces, indicating that this allele could not have been imported to the local breeds through commercial routes.…”

“…The reproduction performance of an animal is of particular economic importance (1,2). Detection of genetic markers, along with mutants of the genes associated with economically important traits, could assist the breeders in designing practical animal breeding plans (1,3).…”

“…Therefore, the sheep's reproductive performance is influenced by both minor and major gene effects. Thus far, the effect on litter size of a number of genes, localized on sexual (X) and autosomal chromosomes (pair 11), have been reported (3)(4)(5)(6). The Booroola sheep are carriers of an autosomal gene named FecB (4,(6)(7)(8).…”

“…Each mutant gene results in an increase to the ovulation rate of 1.6 times (4). It has also been recognized that the Booroola phenotype is correlated to the bone morphogenic receptor-IB (BMPR-IB) (2,3). To identify this point mutation, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), using a short-acting enzyme of AvaΠ that cuts the 6/6 ACC locus, was utilized and the results indicated that noncarrier animals are free of this locus (22)(23)(24)(25)(26).…”