Identification of Booroola carriers using microsatellite markers (Reprinted)

The position of the Booroola locus (FecB) on the sheep chromosome 6 genetic linkage map was further refined by the addition of two microsatellite loci , McM53 and OarJL1A, and a gene locus centromere autoantigen E (CENPE), bet ween epidermal growth factor (EGF) and OarAE101. FecB mapped to a 10 cM reg ion between BM 1329 and OarAE101. These two markers, along with a third unp ublished microsatellite marker, were used to test the inheritance of the ch romosome region around FecB in a Romney introgression project. The genotype s of 15 rams were predicted by marker analysis and validated by progeny tes t data from mating with non-carrier (++);dams. There were five homozygous ( BB) carriers (87% to 94% of daughters with ovulation rates greater than or equal to 3), eight heterozygous (B+) carriers (40% to. 66% of daughters wit h ovulation rates greater than or equal to 3), and two non-carriers (6% to 11% of daughters with ovulation rates greater than or equal to 3). Anomalie s in the phenotype data were overcome by the use of the marker test. This m arker test will advance the progress of a Booroola introgression programme, provided phase can be established by knowing the FecB carrier status of at least one animal in a pedigree.