43. Short answer questions V

 

The sex of offspring depends on the type of sex chromosome the gamete contributes. Two types of sperm are produced by one male, 22 + X by one type and 22 + X22 + Y22 + Z by another. Therefore, 50 per cent of a male's sperms is X, and 50 per cent of the other sperms has X spermsY spermsZ sperms, respectively. The egg can be fertilised by either of the two sperm types. If the Y bearing sperm makes the egg fertiliser, the zygote shall be maleXYXXXZ , and the resulting zygote shall be female when X bears the sperm XX. As in a male gamete, the X chromosome ratio and the Y chromosome is 50: 50. The statistical chance of infants being born to men or women is 50: 50.