Answer: A=0%
The mother allele is Xx and the XY.
The mother and father are heterozygous for the traits.
Explanation:
This is because the mother (Xx) carries a trait for color blindness. Which she inherited from her father who is color blinded that is XY.
The x -chromosomes carries the color blinded trait.
When she is crossed with her color blinded male, the first boy XY will not be color blinded :
Because the boy will pick Nomal X chromosomes from the mother, and and Y chromosomes from the father to form XY. The male sex chromosomes.
Since this is a monohybrid cross,
4 offspring are produced 2 girls and 2 boys .
Genotypes-XY(first boy), Yx Xx, xx .
This a factor of 4 so the first child probability is ZERO. Since 0 divided by 4 = 0
Since no allele with color blinded gene is inherited.
