A condition known as icthyosis hystrix gravior appeared in a boy in the early eighteenth century. His skin became thick and formed loose spines that were sloughed off at intervals. When he grew up theis “porcupine man” married and had six sons, all of whom had this condition and several daughters all of whom were normal. for four generations this condition was passed from father to son. from this evidence what can you postulate about the location of the gene?