Genetic characterization of a sheep-dwarf goat hybrid

Twelve weeks after repeated spontaneous mating between a Bentheimer Landschaf ram and a West African dwarf doe was observed, the doe aborted a dead fetus. The aim of this study was to verify the parentage and the species of the supposed parents and the hybrid status of the fetus, using cytogenetic and molecular genetic methods. For this purpose, karyotypes were prepared using fresh blood samples from the ram and the doe, and genomic DNA was extracted from blood of the suspected parents and tissue of the aborted fetus. Fragments of the nuclear DNA-encoded interleukin-2 gene and the mitochondrial DNA-encoded 16S ribosomal RNA were sequenced and 19 microsatellites were genotyped in all 3 animals. The karyotypes and DNA sequences of the ram and the doe corresponded to domestic sheep and goat, respectively. The interleukin-2 sequence of the fetus was heterozygous at all positions where sheep and goat have different nucleotides. None of the 19 microsatellites excluded the ram and the dwarf doe as parents of the fetus. Taken together, we can conclude that the ram and the dwarf doe were from the species Ovis aries and Capra hircus, respectively, and that they were most likely the parents of the aborted fetus, which itself proved to be a hybrid of these 2 species.