1. MEIOSIS Its Role in Genetics

2. Meiosis plays a very important part in genetic variation There are two main ways meiosis creates genetic differences

3. THE FIRST WAY GENES SEGREGATE Meiosis creates genetic variances through the different ways in which parents’ chromosomes are combined in the daughter cells.

5. The number of possible chromosome combinations in the daughter cells has the potential to be really huge! The number of possible chromosome combinations is 2 n n= # of chromosome pairs

6. Fruit flies have 4 chromosome pairs – The number of possible combinations is 2 n – n=4 (# of chromosome pairs) – 2 4 = 16 – Fruit flies have 16 possible combinations For us, with our 23 chromosome pairs, there are over 8 million possible combinations

7. THE SECOND WAY GENES SEGREGATE The other way meiosis creates genetic variance is through the process of crossing- over Remember that crossing-over occurs during Prophase I

8. Crossing-over results in a physical exchange of equal pieces of maternal and paternal chromosomes that have similar DNA.