Q. MHC class I is a molecule involved in immune system. In mice, class I MHC is derived from 2 (sometimes 3, but we will ignore that for now) loci- D and K, with several alleles possible at each loci- including d,b, and k. Expression of class I derived from these loci involves another molecule, ?2m (beta-2-microglobulin) that is coded for at another locus. An inbred mouse that expresses Db and Kb is crossed with an inbred mouse that expresses no class I MHC. The F1 offspring are all DbKbKk.

1. What is the interaction of different alleles at class I K locus?

2. What is the genotype of the parent not expressing any class I MHC (including class I MHC and ?2m)?

3. What are the expected genotypes of F2?

4. What are the expected phenotypes of F2?

5. What are the ratios of the phenotypes in F2?