Question

A mysterious condition from the early 1800s was noted in a young boy, resulting in severe facial scarring. He grew up to father 17 children including 9 daughters and 8 sons. None of his daughters presented with the condition while all his sons did. Considering that for the next 6 generations this condition was transmitted along the paternal lineage, what can you theorise about the location of this gene and why?

Answer 1

Pedigree analysis suggests that Y-linked traits never occur in females but inherited in all male descendants of an affected male. In the above case, severe facial scarring is appearing to be an example of Y-linked trait. No other condition like autosomal aur X-linked inheritance of the given trait is seen in succesive 6 generation. If it is predicted that the inheritance pattern is Y-linked then offcourse gene of this trait is located on Y chromosome of 23rd pair of chromosome.