Meiosis

This lesson covers:

  1. What 'meiosis' is
  2. The stages of meiosis 
  3. The differences between meiosis and mitosis 

Overview of meiosis 

Meiosis is a type of cell division in which a parent cell divides to form four haploid cells, each genetically distinct from one another.


Before meiosis starts, DNA is replicated during interphase so that each chromosome contains two chromatids. 

Diagram showing the stages of meiosis including DNA replication, meiosis I, and meiosis II resulting in four haploid daughter cells.

The cell then undergoes 2 divisions: 

  1. Meiosis I - Homologous chromosomes are separated. 
  2. Meiosis II - Chromatids are separated. 


Meiosis involves a reduction division in which the chromosome number is halved to form haploid cells. These haploid cells form the gametes (egg and sperm cells) in animals and plants. 

Stages of meiosis 

The two divisions of meiosis contain the same stages as mitosis: 

  1. Meiosis I - Prophase I, metaphase I, anaphase I, and telophase I. 
  2. Meiosis II - Prophase II, metaphase II, anaphase II, and telophase II. 


Remember that cells have already replicated their DNA during interphase and each chromosome is made up of two identical sister chromatids. 

Diagram showing stages of meiosis with chromosomes and spindle fibers.

Prophase I

The chromosomes condense and homologous chromosomes pair up. 


Centrioles migrate to opposite poles of the cell where each centriole starts forming spindle fibres. 


The nucleolus disappears and the nuclear envelope starts to break down, leaving the chromosomes free in the cytoplasm. 

Diagram showing the stages of meiosis with chromosomes aligning in the center of the cell.

Metaphase I

Chromosomes line up along the equator of the cell in their homologous pairs (so in humans, 23 pairs line up).


Each chromosome attaches to the spindle by their centromere. 

Diagram showing stages of meiosis with chromosomes and spindle fibers.

Anaphase I

Homologous chromosome pairs are separated and pulled to opposite poles of the cell (chromatids stay joined together). 

Diagram showing the stages of meiosis with two cells in division.

Telophase I

The chromosomes reach the opposite poles of the cell where they uncoil. 


A nuclear envelope forms around each set of chromosomes and the nucleolus starts to reform. 


The cytoplasm divides to form two cells (cytokinesis). 

Diagram showing the stages of meiosis with chromosomes and cell division phases.

Prophase II

The chromosomes condense and are now visible under a microscope. 


Centrioles migrate to opposite poles of the cell where each centriole starts forming spindle fibres. 


The nucleolus disappears and the nuclear envelope starts to break down. 

Illustration showing the stages of meiosis with chromosomes and spindle fibers.

Metaphase II

The chromosomes line up at the equator of the cell (so in humans, 23 chromosomes line up). 


Each chromosome attaches to the spindle by their centromere. 

Illustration showing stages of meiosis with chromosomes and spindle fibers.

Anaphase II

The centromeres divide and separate each pair of chromatids. 


The spindle fibres contract and shorten to pull the chromatids to opposite poles of the cell. 

Diagram showing stages of meiosis with cells undergoing division.

Telophase II

The chromatids reach the opposite poles of the cell where they uncoil to become long and thin again. 


A nuclear envelope forms around each set of chromosomes to form two nuclei and the nucleolus starts to reform. 


The cytoplasm divides (cytokinesis) and 4 cells are produced. 

Comparing mitosis and meiosis

Table comparing mitosis and meiosis including function, type of reproduction, cell type produced, number of daughter cells, number of cell divisions, genetic variation, and separation of homologous chromosomes.