Meiosis involves two cell divisions that result in four haploid cells from one diploid cell. Meiosis I is the reduction division where homologous chromosomes separate and half the number of chromosomes are in each daughter cell. Meiosis II is similar to mitosis, where each daughter cell from Meiosis I divides to produce a total of four haploid cells that can fuse during fertilization. Crossing over and independent assortment of homologous chromosomes during Meiosis I introduces genetic variation.

1. Meiosis
• Chromosomes
• Nuclear
envelope
• Cell membrane
• Centrioles
ALBIO9700/2006JK

2. • Involves 2 divisions:
i) Meiosis I – reduction division (resulting
in 2 daughter nuclei with half the number
of chromosomes of the parent nucleus
ii) Meiosis II – chromosomes behave as in
mitosis (each of the 2 haploid daughter
nuclei divides, resulting in a total of 4
haploid nuclei)
ALBIO9700/2006JK

3. Centrioles?
Prophase I
Nuclear envelope?
Nucleolus?
Synapsis
Metaphase I *bivalent
Prophase II Anaphase I
Telophase I
Metaphase II Cytokinesis?
Anaphase II
Telophase II
ALBIO9700/2006JK

4. Variation
• Crossing over
• Independent assortment of
homologous chromosome
• Fertilisation
ALBIO9700/2006JK

5. • Locus
• Alleles
• Dominant
• Recessive
• Codominant
• Homozygous
• Heterozygous
• Phenotype
• Genotype
ALBIO9700/2006JK

6. • Locus
• Alleles
• Dominant
• Recessive
• Codominant
• Homozygous
• Heterozygous
• Phenotype
• Genotype
ALBIO9700/2006JK