Define the term allele as used in genetics.

List the possible genotypes for blood group B.

allele: one specific form of a gene (occupying the same gene locus as other alleles of the same gene)

I^BI^B and I^Bi

Most candidates could recall a definition of an allele.

Many candidates did not use appropriate notation and did not score a mark. The Biology subject guide is very clear that candidates must use the I^A, I^B, i notation for the relevant alleles