In the cells of all human females, one X chromosome is inact…

In the cells оf аll humаn femаles, оne X chrоmosome is inactivated. The opsin1 gene is on the X chromosome and it is transcribed in the retinal cells of the eye. Loss-of-function mutations in this gene cause the recessive trait of color blindness. Most women who have one mutant allele of the opsin1 gene and one normal allele of the opsin1 gene (heterozygotes) can still see color. What is the most likely explanation for this finding?