A comparison of Meiosis and Mitosis

Mitosis Occurs in somatic cells, whereas meiosis occurs in reproductive cells. Mitosis only has one nuclear division, so cytokinesis only occurs once, whereas meiosis has two, meiosis I and meiosis II, and therefore cytokinesis occurs once or twice. Since mitosis is very similar to Meiosis II, the differences mainly occur in Meiosis I. Mitosis involves the division of chromosomes, yet meiosis involves the separation of homologous chromosomes in M I and division of chromosomes in MII.

In mitosis the dividing cells are diploid or haploid, but in meiosis, they have to be diploid. Mitosis does not involve either the pairing of homologous chromosomes or crossing over. During Prophase (prophase I in meiosis I and just regular prophase in mitosis) synapsis (pairing of homologues) occurs to form the bivalent and crossing over occurs, resulting in the formation of chiasmata. In mitosis, neither synapse nor crossing over occurs.

During metaphase in meiosis I, bivalents align on the metaphase plate. In mitosis however, individual chromosomes align on the metaphase plate.

In mitosis, the number of chromosomes present in the mother cell is maintained in both the daughter cells; therefore it can be called an equational division. In meiosis, the diploid number of chromosomes is reduced to a haploid in each daughter cell, and is therefore called a reduction division.

Original characteristics of the chromosomes are maintained by mitosis, but in meiosis they are altered by the crossing over causing recombination genes.

         During Anaphase I in meiosis Centromeres do not divide and sister chromatids do not separate. Sister chromatids of each chromosome move to the same pole of the cell, only the homologues separate. Conversely, in anaphase during mitosis, Centromeres divide and sister chromatids move to opposite poles of the cell.

Here is a summary of the differences between the two: