Genome Reduction In Yeast Involves Programmed Cell Death

Abstract

Genetic reduction is of great significance in many biological pathways. In particular, aneuploid cancerous cells typically undergo genetic reduction to obtain a diploid state, a process accompanied by apoptotic programmed cell death. A tetraploid strain of Candida albicans, when grown on a diploid specific pre‐sporulation media, undergoes random chromosome loss, becoming diploid to near‐diploid in DNA content and undergoing significant cell death as part of the completion of a parasexual cycle. Cell death measurements were made for cells grown on pre‐sporulation media plates. Measurements of viability were made with a methylene blue stain, showing significantly lower tetraploid viability. Assays done to determine levels of reactive oxygen species present showed increased concentration in tetraploid cells undergoing genome reduction. Similar results were found in an assay for caspase These results indicate high ROS levels and high levels of caspase activity in the reducing tetraploid, suggestive of apoptosis‐like programmed cell death accompanying genome reduction. Similar results are seen in diploid Saccharomyces cerevisiae. Further research is currently being done with both tetraploid and diploid strands with apoptotic gene knockouts to further understand the mechanism of death, and understanding of these results could aid in understanding of cancerous and other biological mechanisms in humans.