70 Sp 5 and 6. 90 Sp 6. For the Sp 1, Sp 2, Sp 4 and Sp 5 loci, there have been two co dominant alleles. At Sp 3 and Sp 6, one allele was dominant and any other null. Individuals within each locus were classified into phenotypes A, AB and B. Only homozygotes were found at Sp 2.