LOH events in diploid cells can be visualized using colony color phenotypes and, when combined with half-sector analysis, the rate of LOH can be determined [17]–[20]. We used two heterozygous markers that alter colony color when lost: Loss of MET15 function, resulting in a black colony sector, or loss of ADE2 function, resulting in a red colony sector. LOH events that occur within the first cell division after plating will generate sectors that form one half of a colony and can be used as a direct measure of mutation rate.
