3.26: Understand How the Sex of a Person is Controlled by One Pair of Chromosomes, XX in a Female and XY in a Male

While Humans have 46 Chromosomes in all Diploid cells (23 pairs), the 23rd pair are sex chromosomes:

s

• Females possess two copies of the X Chromosome (XX)
• Males possess one X and a shorter Y Chromosome (XY)

DETERMINING GENDER OF OFFSPRING:

GENDER DETERMINATION OF OFFSPRING

Diagram Showing the Chromosome that determines Gender of Offspring

EXPLANATION: Human sex determination occurs according to the X-Y system For Fertilised Embryo to develop into a Female, two copies of the X Chromosome are needed For Fertilised Embryo to develop into a Male, one copy of X and one copy of Y Chromosome is needed Hence, as all Female gametes (Egg cells) only carry copies of X Chromosomes, Male gametes (Sperm Cell) determines the sex of the offspring as they can carry either an X or Y Chromosome, therefore capable of producing a Male or a Female