What does the genotypic cross look like?

Since Mary has brown eyes then the dominant trait would be brown. Therefore, her Gene would be Bb and John's would be bb. The ratio would then result in 1:1 phenotypic and genotypic with offsprings being Bb, Bb, bb and bb

Since Mary has brown eyes then the dominant trait would be brown. Therefore, her Gene would be Bb and John's would be bb. The ratio would then result in 1:1 phenotypic and genotypic with offsprings being Bb, Bb, bb and bb

Mary's father has brown eyes which is either BB or Bb,her mother has blue eyes bb..since Mary has brown eyes, from the crossing of either BB and bb or crossing of Bb and bb, the only correct genotype for Mary is Bb. Therefore the crossing between Mary Bb and John bb will give Bb,Bb,bb and bb.

Because Marys mother has blue eyes, she is heterozygoud dominant or Bb. John has blue eyes which is the recessive trait or bb.