The αS1 casein gene is one of the lacto protein genes, which are involved in the milk synthesis. The objective of this study was to identify genotypes of B and E alleles at the locus αS1 casein in the Guéra and Sahel goat herds in Mali. These herds were located in the Regional Center of Agronomic Research and the Ségala village in Kayes, Mali. A total of 101 blood samples (53 for Guéra goat and 48 for Sahel goats) were collected and analysed. Alleles B and/or E, located on exon 19, of the αS1 casein gene were amplified using allele specific amplification polymerase chain reaction and analysed using 2 percent agarose gel electrophoresis. Results from this analysis identified three genotypes: BB, BE and EE with frequencies 0.77, 0.17 and 0.06 for the Guéra goats. However, only the BB genotype was identified in the Sahel goats. The frequencies of alleles B and E in the Guéra goats were 0.86 and 0.14, respectively, with an observed and expected heterozygotes of 0.08 and 0.12, respectively.

Caseins (αs1, β, αs2, e κ) represent about 80% of the whole protein content of ruminant milk. Each of these proteins is encoded by single copy genes (CSN1S1, CSN2, CSN1S2 and CSN3, respectively) clustered on a ∼200-kb segment of chromosome 6 (Ferretti et al. 1990; Gallagher et al. 1994) in the order: CSN1S1, CSN2, CSN1S2 and CSN3 (Mercier & Vilotte, 1993). Furthermore, in cattle and goat CSN1S1 and CSN2 are convergently transcribed (Leroux & Martin, 1996; Rijnkles et al. 1997) and are only 20 and 12 kb apart, respectively.