What is the purpose of meiosis?
Meiosis is a specialized type of cell division that allows for the production of gametes
in sexually reproducing organisms. Unlike mitosis, meiosis occurs only in germ cells
and involves two rounds of cell division, known as meiosis I and meiosis II.
During meiosis I, homologous chromosomes pair up and exchange genetic material
in a process called crossing over. This helps to increase genetic diversity in
offspring. Then, the homologous chromosomes separate from each other and are
pulled to opposite ends of the cell.
In meiosis II, the sister chromatids of each chromosome separate from each other
and are pulled to opposite ends of the cell. Four haploid daughter cells are produced,
each with half the number of chromosomes as the parent cell. These haploid cells
can then combine with another haploid cell during fertilization to produce a new,
genetically diverse diploid organism.
The purpose of meiosis is to ensure genetic diversity in offspring. By randomly
shuffling genetic material, meiosis allows for the creation of unique combinations of
alleles in offspring, increasing the potential for adaptation to changing environments.
Additionally, meiosis ensures that the number of chromosomes in offspring is
reduced to half that of the parent cells, allowing for the restoration of the diploid
number of chromosomes during fertilization.
References:
1. Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2002). Molecular
Biology of the Cell. New York: Garland Science.
2. Lodish, H., Berk, A., Zipursky, S. L., Matsudaira, P., Baltimore, D., & Darnell, J. (2000).
Molecular Cell Biology. New York: W. H. Freeman.
3. Sadava, D., Hillis, D., Heller, H. C., & Berenbaum, M. R. (2011). Life: The Science of
Biology. Sunderland, MA: Sinauer Associates.