A color-blind woman marries a man who is not color-blind. All of their sons are color-blind, but none of their daughters are color-blind. Color-blindness is likely
A. the result of having too few chromosomes.
B. the result of having an extra chromosome.
C. a sex-linked trait.
D. a recessive trait.
What is your answer?
Yes, c.
c i think
The correct answer is C. Color-blindness is a sex-linked trait.
To understand why this is the likely answer, let me explain it further. Color blindness is a condition that affects a person's ability to distinguish colors. It is primarily caused by an inherited genetic mutation on the X chromosome.
In humans, females typically have two X chromosomes (XX), while males have one X and one Y chromosome (XY). Since color blindness is a sex-linked trait, it is more common in males because they have a higher chance of inheriting the mutated gene.
In the given scenario, the woman is color-blind, which means she carries the mutation on one of her X chromosomes. The man, being non-color blind, has two normal X chromosomes (XY). When they have children, there is a 50% chance for each child to inherit the color-blindness gene.
Their sons have a higher likelihood of being color-blind because if they inherit their mother's X chromosome with the mutated gene, they will be affected. Since the mother is color-blind, all of her sons inherit the X chromosome with the genetic mutation.
On the other hand, their daughters have a lower chance of being color-blind because they inherit one normal X chromosome from their father, which compensates for the mutated X chromosome from their mother. Therefore, none of their daughters will be color-blind, but they may carry the gene and pass it on to their children in the future.
To summarize, color blindness is a sex-linked trait that is typically inherited on the X chromosome, and in this case, it explains why all their sons are color-blind, while none of their daughters are affected. Therefore, option C is the correct answer.