C. Tongue rolling
D. Colour blindness
Sex-link character is often a disorder found to be mostly prevalent on a particular sex. They are often hereditary and could be traced to a particular chromosome.
Now for the right answer to the above question:
- Dwarfism is a trait evenly found in both male and female, the trait of dwarfism is not limited to a particular chromosome. so, A is incorrect.
- Albinism is a defect found to affect both male and female in almost equal proportion, the trait of albinism is not also limited to a particular sex chromosome. B is also incorrect.
- Tongue rolling also is a character evenly found in both male and female, a person born with one or two dominant allele of the gene for tongue rolling ends up having the ability. This could be male or female. So, C is also incorrect.
- D is correct; colour blindness is a trait that affect vision genes found on the X-chromosome. Now, we know that the X-chromosome is responsible for the conception of the male child, hence colour blindness affects mostly men.
You may please note that:
- The X-chromosome is the male determining factor at conception, any condition that only affects it becomes sex-linked.
Use the questions and answers session to raise further questions and deal more on this topic…
/ culled from 2017 JAMB-UTME biology question 24 /