Question

QUESTION 8

An organism has a normal diploid set of autosomes, with an XO sex chromosome complement. It would be a

a.

female fly, female human being

b.

female fly, male human being

c.

intersex fly, male human being

d.

male fly, female human being

e.

male fly, male human being

Answer 1

The correct option is d.male fly, female human being.

The sex-determination systems in mammals and in insects are very different. In mammals, the Y chromosome plays an essential role in determination in sex of male. Therefore, XO mammals are females, with ovaries, a uterus and oviducts. In flies, sex determination is completed by a balance of female determinants on the X chromosome and male determinants on the autosomes. If there is but one X chromosome in a diploid cell, the fly is male. If there are two X chromosomes in a diploid cell, the fly is female. Therefore, XO flies are sterile males.