How do the new cells that result from meiosis differ from the new cells that result from mitosis?

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

Further Reading

• All Meiosis Content
• Meiosis Process

Last updated Feb 26, 2019

Mitosis and meiosis, which are both forms of division of the nucleus in eukaryotic cells, share some similarities, but also exhibit distinct differences that lead to their very different outcomes. Mitosis is a single nuclear division that results in two nuclei, usually partitioned into two new cells. The nuclei resulting from a mitotic division are genetically identical to the original. They have the same number of sets of chromosomes: one in the case of haploid cells, and two in the case of diploid cells. On the other hand, meiosis is two nuclear divisions that result in four nuclei, usually partitioned into four new cells. The nuclei resulting from meiosis are never genetically identical, and they contain one chromosome set only—this is half the number of the original cell, which was diploid.

The differences in the outcomes of meiosis and mitosis occur because of differences in the behavior of the chromosomes during each process. Most of these differences in the processes occur in meiosis I, which is a very different nuclear division than mitosis. In meiosis I, the homologous chromosome pairs become associated with each other, are bound together, experience chiasmata and crossover between sister chromatids, and line up along the metaphase plate in tetrads with spindle fibers from opposite spindle poles attached to each kinetochore of a homolog in a tetrad. All of these events occur only in meiosis I, never in mitosis.

Homologous chromosomes move to opposite poles during meiosis I so the number of sets of chromosomes in each nucleus-to-be is reduced from two to one. For this reason, meiosis I is referred to as a reduction division. There is no such reduction in ploidy level in mitosis.

Meiosis II is much more analogous to a mitotic division. In this case, duplicated chromosomes (only one set of them) line up at the center of the cell with divided kinetochores attached to spindle fibers from opposite poles. During anaphase II, as in mitotic anaphase, the kinetochores divide and one sister chromatid is pulled to one pole and the other sister chromatid is pulled to the other pole. If it were not for the fact that there had been crossovers, the two products of each meiosis II division would be identical as in mitosis; instead, they are different because there has always been at least one crossover per chromosome. Meiosis II is not a reduction division because, although there are fewer copies of the genome in the resulting cells, there is still one set of chromosomes, as there was at the end of meiosis I.

Cells produced by mitosis will function in different parts of the body as a part of growth or replacing dead or damaged cells. They may even be involved in asexual reproduction in some organisms. Cells produced by meiosis in a diploid-dominant organism such as an animal will only participate in sexual reproduction.

Figure 1 Meiosis and mitosis are both preceded by one round of DNA replication; however, meiosis includes two nuclear divisions. The four daughter cells resulting from meiosis are haploid and genetically distinct. The daughter cells resulting from mitosis are diploid and identical to the parent cell.

Unless otherwise noted, images on this page are licensed under CC-BY 4.0 by OpenStax.

OpenStax, Biology. OpenStax CNX. May 27, 2016http://cnx.org/contents/:1Q8z96mT@4/Meiosis

There are two types of cell division: mitosis and meiosis. Most of the time when people refer to “cell division,” they mean mitosis, the process of making new body cells. Meiosis is the type of cell division that creates egg and sperm cells.

Mitosis is a fundamental process for life. During mitosis, a cell duplicates all of its contents, including its chromosomes, and splits to form two identical daughter cells. Because this process is so critical, the steps of mitosis are carefully controlled by certain genes. When mitosis is not regulated correctly, health problems such as cancer can result.

The other type of cell division, meiosis, ensures that humans have the same number of chromosomes in each generation. It is a two-step process that reduces the chromosome number by half—from 46 to 23—to form sperm and egg cells. When the sperm and egg cells unite at conception, each contributes 23 chromosomes so the resulting embryo will have the usual 46. Meiosis also allows genetic variation through a process of gene shuffling while the cells are dividing.