by Karen Griffiths
The red queen hypothesis describes ideas based on co-evolution. According to the red queen hypothesis, sexual reproduction persists because it enables hots species to evolve new genetic defenses against the parasites that attempt to live on them. However, simple evolution is not enought to protect the host species, there must be a co-evolution between host and parasite. This is because as the parasite species evolves new receptors to bind to a host cells and infect it, the host must evolve to in order to survive. In short a change in one species, could lead to the extinction of the other species. Therefore there is a constant arms race between species (ie host & parasite, predator & prey), where they must evolve in order to survive, or 'run' to stay in the same place.
The phrase "Red Queen hypothesis" comes from Chapter 2 in Through the Looking Glass (Carroll 1872). Alice decides that it would be easier to see the garden a garden if she first climbs the hill, to which there appears to be a very straight path. However, as she follows the path, she finds that it leads her back to a house. When she tries to speed up, she not only returns to the house, she crashes into it. Hence, forward movement takes Alice back to her starting point (Red Queen dynamics), and rapid movement causes abrupt stops (extinction) (Lively)
The other idea described by the hypothesis is that co-evolution leads to occilations in gene frequencies which leads to the persistance of sexual reproduction over asexual reproduction. This hypothesis is is illustrated well in fish (Lively et. al., 1990), where the asexually reproducing individuals were shown to harbour more parasites than the sexually reproducing species, demonstrating the co-evolution favour sexually reproducing species and seperate sexes.
Additionally, while sex can be a costly investment and asexually reproducing females will out compete sexually repoducing females, and rare genes may be lost; it allows for genetic and heritable variation. The advantages include the generation of new alleles, the resuffling of genes and the purging of diadvantagous mutations.
References
Carrol, L. (1872) Through the looking glass and what Alice found there. Macmillan, London
Lively CM, Craddock C, & Vrijenhoek RC (1990) Red Queen hypothesis supported by parasitism in sexual and clonal fish. Nature 344: 864-866
Lively C, Red Queen Hypothesis http://www.indiana.edu/~curtweb/home.html
The phrase "Red Queen hypothesis" comes from Chapter 2 in Through the Looking Glass (Carroll 1872). Alice decides that it would be easier to see the garden a garden if she first climbs the hill, to which there appears to be a very straight path. However, as she follows the path, she finds that it leads her back to a house. When she tries to speed up, she not only returns to the house, she crashes into it. Hence, forward movement takes Alice back to her starting point (Red Queen dynamics), and rapid movement causes abrupt stops (extinction) (Lively)
The other idea described by the hypothesis is that co-evolution leads to occilations in gene frequencies which leads to the persistance of sexual reproduction over asexual reproduction. This hypothesis is is illustrated well in fish (Lively et. al., 1990), where the asexually reproducing individuals were shown to harbour more parasites than the sexually reproducing species, demonstrating the co-evolution favour sexually reproducing species and seperate sexes.
Additionally, while sex can be a costly investment and asexually reproducing females will out compete sexually repoducing females, and rare genes may be lost; it allows for genetic and heritable variation. The advantages include the generation of new alleles, the resuffling of genes and the purging of diadvantagous mutations.
References
Carrol, L. (1872) Through the looking glass and what Alice found there. Macmillan, London
Lively CM, Craddock C, & Vrijenhoek RC (1990) Red Queen hypothesis supported by parasitism in sexual and clonal fish. Nature 344: 864-866
Lively C, Red Queen Hypothesis http://www.indiana.edu/~curtweb/home.html