1. Meiosis
Division of Gametes

2. Somatic Cells vs. Gametes
Somatic cells-body cells, are diploid (2n) and have 2 sets of chromosomes (one from each parent)
Gametes-sex cells (sperm and eggs), are haploid (n) and have 1 set of chromosomes

3. How do we get haploid gametes?
Meiosis!
Needed so that when gametes join together in fertilization, the zygote the create is diploid
Results in 4 NON-identical haploid daughter cells

4. Homologous Chromosomes
Chromosomes THAT HAVE THE GENES FOR THE SAME TRAIT
ONE FROM EACH PARENT
Form a tetrad

5. Meiosis Meiosis 1: First Division of Meiosis
prophase I: similar to prophase in mitosis
metaphase I: the homologous chromosomes line up at the equator
anaphase I: the homologous chromosomes separate to opposite poles
telophase I: similar to telophase in mitosis (results in 2 haploid nuclei)

7. Meiosis
Meiosis II: the 2 daughter cells go through a second division, resulting in 4 haploid, non-identical daughter cells total.

9. Crossing over
During meiosis I, when homologous chromosomes form a tetrad, crossing over can occur.
Alleles are exchanged between homologous chromosomes