All the sons of a colour-blind woman will be coloured blind regardless of the state of the father because
the egg determines the phenotype of the son
sons inherit the sex chromosome of their mothers
the father's sex chromosomes is weaker in sons
sex-linked traits express dominance in females
Explanation
Video Explanation
No video available
Post your Contribution
Discussions (22)
B is correct
s*x-linked trait does not express itself dominant in females and it is rare
The females must inherit a recessive X-linked alleles from both of their parents inorder to express the trait(color blindness) This is why option D is wrong
However Males, who have only a single copy of the X chromosome, are more likely to be affected by a s*x-linked disorder than females, who have two copies.
So option B is correct
This question is quite something confusing, B and D options are correct if you look at them from two different perspective 😄.
I think for this question, option D would have been Undisputably correct if it ended with “Males" and not “Females".
For option B, it is correct because truly, Males inherit their mother's X-chromosomes and without a choice, the male-child expresses whatever s*x linked trait the mother carries.
I believe B is a more suitable answer. Thanks
Let’s assume the allele for color blindness is cc for it to be expressed.
A colored blind woman has both recessive (cc) in her XX Chromosome. And in s*x determination for a male one X chromosome from the mother is taken and one Y chromosome from the father is taken together to form Xy
s*x linked characters are only present in the X chromosome.
Since the mother has both ‘cc’ for color blindness (she is color blind )
All her X chromosome carries this trait which will be passed to her sons on his X chromosome.
Males cannot show heterozygosity for s*x link traits once the mother is a suffer for that trait he MUST be a suffer too.
This means that the son inherit the s*x chromosome of their mothers.
The correct answer is B.
Sons inherit one of their mother's s*x chromosomes, specifically the X chromosome, and the father contributes either an X or a Y chromosome. Color blindness is a s*x-linked trait that is carried on the X chromosome. If the mother is color-blind, she will have two X chromosomes with the color blindness gene, and she will pass one of these X chromosomes to each of her sons. Since males only inherit one X chromosome, they will be color-blind if that X chromosome carries the color blindness gene.
