Summary
The responses to UV irradiation of pre-meiotic and meiotic cells of the unicellular green alga Chlamydomonas reinhardi have been examined in a wild type and a UV-sensitive mutant (UVS1) strain. During late interphase and early prophase the cells become highly sensitive to UV under dark conditions, but show much less change in sensitivity following photoreactivation (PR). At these times the effect of PR is not dose-modifying, but very large PR factors are obtained — at the 50% survival level in some stages values up to 23 being obtained. The enhancement of dark sensitivity is attributed to a diminution in dark repair activity, and it is suggested that this is associated with the process of genetic recombination that occurs in these meiotic cells. In addition at those times when the dark repair capacity is at a low level, a phenomenon akin to UV reactivation occurs, in that within a certain dose range, survival increases with increasing dose. The possible basis of this phenomenon is discussed.
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Roy Davies, D. The control of dark repair mechanisms in meiotic cells. Molec. Gen. Genetics 100, 140–149 (1967). https://doi.org/10.1007/BF00333600
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DOI: https://doi.org/10.1007/BF00333600