Question

The family tree below shows the trait of color blindness. The only unknown is the mother in the first generation.

What must be true about the mother?
A. She is color-blind.
B. She has two recessive color blindness alleles.
C. She has at least one recessive color blindness allele.
D. She only has one X chromosome.

Answer 1

"She has at least one recessive color blindness allele" is the one statement among the following choices given in the question that is true. The correct option among all the options that are given in the question is the third option or option "C". I hope that this is the answer that has actually come to your desired help.

Answer 2

The right answer is C.

Color blindness a disease transmitted genetically by the mother (mostly) on the X chromosome. This is the chromosome that determines the sex of the child.

*For a boy to suffer from red-green daltonism, his X chromosome must carry the defective colorblind gene.

*For girls, the defective gene must be present on both X chromosomes, hence the highest prevalence of red-green daltonism in boys.