Prolificacy genotypes at BMPR 1B, BMP15 and GDF9 genes in North African sheep breeds

The aim of this research was to investigate the genetic structure at BMPR 1B, BMP15 and GDF9 prolificacy genes in five sheep breeds reared in Tunisia: Barbarine, Queue Fine de L’Ouest, Noire de Thibar, Sicilo-Sarde and D’man. Genomic DNA of 204 sheep was investigated for the FecBB (BMPR 1B), FecXR, FecXH, FecXI, FecXL, FecXG, FecXB (BMP15) and FecGH (GDF9) mutations. The sequence variability of the different DNA fragments utilised for genotyping was further investigated by Single Stranded Conformation Polymorphism (SSCP) and sequencing. All the above-mentioned mutations were absent in the five sheep breeds examined. SSCP analysis and sequencing allowed the detection of two nucleotide variations. A non-functional mutation (T/C transition at nt 747 of BMP15 cDNA known as B3) was found at the BMP15 gene, in the Noire de Thibar breed; this mutation was first detected in the Belclare sheep. A new nucleotide change G/A at nt 1159 of BMP15 cDNA, causing the amino acid change A119T in the mature peptide, was detected in the Barbarine breed for the first time. The highly prolific D’man ewes were monomorphic for the absence of all the known prolificacy alleles.