Brown eyes are dominant over blue eyes. In addition, colour blindness(n) is sex- linked. What type of offspring would be produced from the following cross? BbXNXN      and      BbXnY

Expert Answers
jerichorayel eNotes educator| Certified Educator

Both of the parents are heterozygous brown eyes (Bb). Doing the punnet square the results would be:

         B      b

B      BB    Bb

b      Bb    bb


50% Heterozygous brown eyes

25% Homozygous brown eyes

25% blue eyes (recessive trait)


For the x-linked trait color blindness, the resulting offspring would be:


Male: `X^nY` -> color blind male

Female: `X^NX^N` -> Normal female


                 `X^n`          `Y`

`X^N`    `X^NX^n`   `X^NY`

`X^N`    `X^NX^n`   `X^NY`



50% Carrier female

50% Normal male