Meiosis is a specialized form of cell division that takes place in the germ-line cells of organisms that utilize sexual reproduction. Like mitosis, it requires the duplication of DNA and the division of a cell into daughter cells, but unlike mitosis it requires two cell divisions and produces haploid cells, called gametes. Also, while mitosis produces cells that are exact copies of the parent cell, meiosis enables variability in cells through the independent assortment of chromosomes and through crossing-over between homologous chromosomes. The foundation for understanding inheritance was established by the work of Gregor Mendel in the mid-1800s. Our current understanding of meiosis enables us to grasp the causes of the effects he observed.
At A Glance
-
Meiosis occurs in cells (called germ-line cells) that produce gametes, specialized cells involved only in the reproduction of plants, animals, and fungi that undergo sexual reproduction.
- Meiosis is more complex than mitosis, requiring two rounds of cell division.
- Meiosis is a specialized form of nuclear division, resulting in gametes that are haploid daughter cells.
-
Errors during meiosis may result in the formation of gametes with too many or too few chromosomes.
-
Mendel's work revealed the fundamental laws of inheritance and formed the basis for genetic study.
- Crossing-over results in new combinations of genes, so one aspect of meiosis is that it enables the genetic variability necessary for evolution.
