Question

two brown-eyed parents have produced three blue-eyed sons. what can be concluded about the parents?a)only the father carries an allele for blue eyes. b)only the mother carries a dominant allele for blue eyes. c)the allele for blue eyes is on the father's y chromosome. d)they both carry a recessive allele for blue eyes.

Answer 1

they both carry a recessive allele for blue eyes because answer A doesnt state anything about the allele dominance, answer B wouldnt be right because if blue eyes was dominant then the mother would have blue eyes as the dominant gene always shows, but she has brown

Answer 2

Option D,they both carry a recessive allele for blue eyes.

Step-by-step explanation:

A recessive allele is expressed only when the recessive allele are in pairs.

In this case, if "B" represents brown color of eye and "b" represents blue color of eye, then the genotype of blue eyed sons would be "bb"

Thus, both the parents must be a carrier of recessive allele so that each of them can contribute one blue color allele to their son.

Hence option D is correct.