ABSTRACT
Bovine cDNA probes for the beta-subunit of follicle-stimulating hormone beta (FSH beta) and the alpha-subunit of the glycoprotein hormones identify genetic variation (polymorphic restriction fragments) near these genes in sheep. The inheritance of the polymorphic restriction fragments was studied in half-sibling pedigrees generated by mating heterozygous (B+) rams to non-carrier (++) ewes so that the co-inheritance or genetic linkage to the Booroola (FecB) locus and the alpha- and beta-subunits of FSH could be analysed. Genetic recombination was observed between the FSH beta locus and the FecB locus in all five families studied and between the alpha-subunit and the FecB locus in the two families studied. We conclude that the FecB mutation does not lie within the FSH beta- or alpha-subunit genes encoding the heterodimeric hormone FSH, and that the high concentrations of FSH observed in carrier ewes must result from indirect actions of the FecB mutation on the synthesis, processing, storage, release or metabolism of FSH.
Subject(s)
Follicle Stimulating Hormone/genetics , Genetic Variation/genetics , Glycoprotein Hormones, alpha Subunit/genetics , Mutation/genetics , Sheep/genetics , Animals , Breeding , Female , Fertility/genetics , Follicle Stimulating Hormone, beta Subunit , Genetic Linkage/genetics , Polymorphism, Restriction Fragment LengthABSTRACT
A selection of cattle, human and sheep cDNA probes were screened against sheep genomic DNA, cut with 10 different restriction enzymes, to assess the usefulness of these probes for restriction fragment length polymorphism (RFLP) linkage studies in sheep. Two-thirds of the cattle cDNA probes showed moderate to strong homology with sheep DNA samples, compared with less than half of the human cDNA probes at the final washing stringency chosen for the experiments. The set of probes tested detected a useful frequency of RFLPs. Fifty-seven per cent of probes showing moderate to strong homology identified RFLPs with one or more restriction enzymes. Restriction enzymes that detected RFLPs most frequently in sheep were TaqI and MspI. The results show that sheep and cattle cDNA probes, including candidate genes for production traits, identified a high frequency of RFLPs suitable for genetic mapping in sheep.
