a) Fruit flies that are trisomic for chromosome 2 are usually inviable, and dont survive beyond early embryo genesis. Fruit flies that are trisomic for chromosome 4 are usually viable, ofteneven fertile. Give an explanation for this.

b) Colour blindness in human beings is an X-linked trait. A man who is colour blind has a XO (Turner’s syndrome)daughter who is also colour blind. Did the germ-linenon disjunction that led to the XO child occur in the mother or the father? How can you tell?