Published online by Cambridge University Press: 14 April 2009
The occurrence of induced recombination in the mitotic cell cycle in yeast has been analysed using conditional cell-cycle mutants held at the restrictive temperature. The strains used were heteroallelic at gall and assaying for functional galactokinase shortly after irradiation (Johnston, 1982) allowed an unambiguous determination of the cell cycle stages in which recombination could occur. Recombination was observed in most strains, including those with the cdc36 mutation, defective in ‘start’; the cdc4, 7 and dbf4 mutations which arrest cells in G1; the dbf1, 2 and cdc6 mutations affecting S phase; cdc16 and cdc17 which block cells in G2 and also cdc14 and 15 which arrest cells in ‘late nuclear division’. Recombination can therefore occur within each of the major phases of the yeast cell cycle. This analysis has also revealed that the cdc8 mutation results in a defect in induced mitotic recombination.