Question

Color blindness is a sex-linked trait. if we could see the pedigree chart for the several more generations of the family illustrated here, we would expect

a. more males to be colorblind
b. more females to be colorblind
c. no females to ever be color blind
d. an equal numbers of male and females that are color blind

Answer 1

a. more males to be colorblind
If a female inherits the trait it is unlikely that she would express the trait since she receives two x chromosomes. Males, on the other hand, receive one x chromosome and will express the trait if it is inherited.

Answer 2

The right answer is a. more males to be colorblind

Color blindness has different causes, but in the majority of cases, the disease is hereditary and is transmitted genetically by the mother on the 23rd 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.