Gene conversion of deletions in the his4 region of yeast.

A selection procedure has been devised which allows the recovery of deletions of the his4 region of Saccharomyces cerevisiae. Many deletions were obtained by this procedure and were characterized genetically and biochemically. These deletions permit the construction of a linear map of the his4A and his4B region. A deletion which was large on this genetic map reduced the size of the his4 gene product. Tetrad analyses revealed that deletions can affect the conversion frequency of other alleles at his4. Analysis of reciprocal recombination in conversion tetrads showed that the order of genes on chromosome III is: centromere-leu2-his4A-his4C. This means that in his4 transcription and translation proceed away from the centromere.