1. Mistakes in Meiosis

2. Non-Disjunction a type of mistake in meiosis that happens to the CHROMOSOME It is the failure of homologous chromosomes to separate properly

3. 2 things can happen a) Have extra chromosomes b) Missing chromosomes

4. Extra Chromosomes EX: Down Syndrome When chromosome # 21 does not fully separate, and there is an additional chromosome A person with down syndrome has 3 chromosomes instead of 2, which is called Trisomy 21

6. Extra Chromosome EX: Polyploidy Polyploidy is when there is a total LACK of separation of homologous chromosomes The gamete (sperm/egg) inherits an entire EXTRA set of chromosomes

7. Polyploidy Polyploidy is rare in animals, but if it occurs it will result in death of a zygote BUT, it is frequent in PLANTS Plants that have polyploidy are larger, healthier, and are of greater commercial value

8. Polyploidy

9. Missing Chromosomes If a chromosome is missing, the organism will most likely not survive It is referred to as “monosomy” EX: Turner syndrome

10. Turner Syndrome Human females have only 1 single X chromosome instead of 2 X’s

11. How to detect Genetic Disorders Cells are extracted from a person The Cells are stained to reveal a banding patterns Chromosomes are identified, and arranged in homologous pairs This chart is called a Karyotype, and is used to detect chromosomal abnormalities

13. Chromosome PAIRS 1 -22 are called Autosomes Chromosome Pair 23 is called the sex chromosome XX is female XY is Male Sperm determines the sex of a baby (meaning it’s either X or Y), while the Egg is always X