BY5.4 Sex Linked Inheritance

Sex determinism:

• non sex chromosomes are known as autosomes
• of the 23 pairs of chromosomes, 22 pairs are autosomes and one pair are sex chromosomes
• males have disimilar sex chromosomes: XY
• females have similar sex chromosomes: **
• all female eggs contain X chromosomes
• half of the sperm contain an X chromosome, half contain a Y chromosome
• the fertilised egg is either joined by an X sperm or a Y sperm
  • there is an equal chance of having a boy or  a girl

Sex linked inheritance:

• some alles are carried on the X chromosome
• they are known as being sex linked
• the Y chromosome is smaller than the X and carries very few genes

• sex linkage: recessive genes carried on the X chromosome express themselves…