A condition known as ichthyosis hystrix gravior appeared as a mutation in a boy in the early eighteenth century. His skin became much thickened and formed loose spines that were sloughed off at intervals. When he grew up this ‘porcupine-man’ married and had six sons, all with this condition, and several daughters who were all normal. For four generations this condition was passed from father to son. Where do you suggest the mutated gene was located?
Ichthyosis hystrix gravior is one of the Ichthyosis hystrix skin disorders which is characterized to have scaly skin complexion. This condition was traced from the Royal Lone of Edward Lambert and three of his descendants.
Looking at the conditions, the source of the disease can be a sex-linked trait or autosomal trait. If a disease is autosomal dominant, the offspring only need to get the abnormal gene from one parent in order for him/her to inherit the disease. One of the parents may often have the disease. Since the condition states that the daughters are all normal, the abnormal gene is located in place specific to male offspring. Probably, the abnormal gene is located on the Y chromosome.