L5 - Sex Chromosomes

• Phenotypes can be a result of a selection of genes combined and not just one single gene on its own. An example is height. Your height is controlled by many genes being expressed, making your phenotype (height) what it is.
• Male sex chromosomes are XY
• Female sex chromosomes are XX
• Male gametes (sperm) can either have an X chromosome or a Y chromosome in them (remember that gametes have half the number of chromosomes).
• Females gametes (eggs) only have one X chromosome in them.
• There is a 50% chance that a baby is male and a 50% chance that a baby is female.