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Origin and nature of spontaneous mutations in meiotic organisms

✍ Scribed by Magni, G. E.

Publisher: Wiley (John Wiley & Sons)
Year: 1964
Tongue: English
Weight: 633 KB
Volume: 64
Category: Article
ISSN: 0095-9898
DOI: 10.1002/jcp.1030640413

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✦ Synopsis

Spontaneous reversion rates of biochemical mutants in cells of

Saccharmyces cerevisiae undergoing meiosis are several times higher than those of cells mitotically reproducing. It has been demonstrated that the great majority of revertants occurring during a meiotic process are associated with chromosomal exchanges in the region of the specific locus. This leads to the hypothesis that during meiosis back mutations occur as a consequence of unequal crossing-over causing base losses or insertions in the DNA and, therefore, restroration of a sequence compatible with the synthesis of functioning proteins. The same phenomenon holds true also for forward mutations. Preliminary experiments show that, as expected, mutations due to base substitutions do not revert in meiosis at a rate higher than in mitosis. Exchange-associated mutations seem to occur also in other organisms such as bacteriophages, bacteria, Neurospora, and Drosophilu.

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