Mitosis vs Meiosis

Mitosis and meiosis are both processes by which cells reproduce, but there are distinct differences between the two. While new cells are generated during mitosis, meiosis is a special type of cell division that produces sex cells for reproduction. The two processes were discovered by different scientists. Meiosis was discovered by German biologist Oscar Hertwig while German physician Walther Flemming is credited with the discovery of mitosis.

The Purpose of the Reproduction

Only sexually reproductive organisms utilize meiosis. The role of the process is to produce sex cells and to repair genetic defects in germ line cells (the sex cells).

Both sexual and asexual organisms go through the process of mitosis. It happens in the cells of the body known as the somatic cells and produces cells related to growth and repair. Mitosis is essential for asexual reproduction, regeneration, and growth. It does not make sex cells or gametes.

Number of Daughter Cells

In meiosis, four haploid cells containing half the amount of chromosomes are produced at the end of the process.

Alternatively, two diploid cells, containing two sets of chromosomes, are produced as a result of mitosis.

Composition of the Daughter Cells

The daughter cells produced at the end of meiosis are completely different from the original parent cell and they include a mix of both the maternal and paternal genes, leading to genetic diversity during sexual reproduction.

The daughter cells created in mitosis are genetically the same as the original parent cell.

Phases of Reproduction of the Cells

Meiosis has two phases for the reproduction of cells which results in there being two cell divisions. The first phase includes prophase I  – during which the most important events of meiosis occur, metaphase I, anaphase I, telophase I, and cytokinesis. During the second phase, these processes repeat again with the cells that were formed at the end of the first phase.

In mitosis, the cells divide only once and this is via one phase which includes steps such as prophase, prometaphase, metaphase, anaphase, telophase and cytokinesis.

Pairing of Homologues

Meiosis involves the pairing of homologues, chromosomes similar to other chromosomes, whereas mitosis involves no pairing of homologues.

Differences in Anaphase

During the anaphase of meiosis, the sister chromatids do not separate. In anaphase I, the chromosomes are double-stranded and in Anaphase II, they are single stranded.

During anaphase in mitosis, the sister chromatids do separate at the centromeres and the chromosomes are single stranded.

Differences in Telophase

In mitosis, the spindle fibres recede fully during telophase, but this is not the case with telophase I of meiosis. Also the nucleoli reappear in mitosis but not in meiosis.

Mixing of Chromosomes

In meiosis, the chromosomes cross over causing mixing. Mitosis, on the other hand, does not involve crossing over of the chromosomes.

References

• 5th Period Biology on the differences between mitosis and meiosis: http://5thperiodbiology.blogspot.co.uk/2012/03/mitosis-vs-meiosis-chart.html
• University of Illinois at Chicago on the differences between meiosis and mitosis: http://www.uic.edu/classes/bios/bios100/lectures/mitosis.htm
• Major Differences on mitosis vs meiosis: http://www.majordifferences.com/2013/07/difference-between-mitosis-and-meiosis.html#.VtWC98eyJsM

Further Reading

• All Meiosis Content
• Meiosis Process

Written by

Deborah Fields

Deborah holds a B.Sc. degree in Chemistry from the University of Birmingham and a Postgraduate Diploma in Journalism qualification from Cardiff University. She enjoys writing about the latest innovations. Previously she has worked as an editor of scientific patent information, an education journalist and in communications for innovative healthcare, pharmaceutical and technology organisations. She also loves books and has run a book group for several years. Her enjoyment of fiction extends to writing her own stories for pleasure.