Figure 5: The snowflake yeast body plan ensures genetic segregation.

(a) We model the settling rate of propagules produced by 16-celled snowflake yeast clusters (open circles) or cellular aggregates (filled circles) that contain 50% small and large cells. Snowflake yeast produce offspring in which small- and large-cell alleles are completely segregated into different clusters (resulting in either slow or fast settling speed), while most aggregates contain a mixture of both cell types. (b) We model the probability that a propagule produced by a 256-cell cluster containing both wild-type cells and a mutant lineage will contain only mutant cells as a function of mutant frequency in the cluster. Snowflake yeast clusters have a far higher probability of producing mutant-only propagules than aggregate clusters. (c) Rare mutants in 256-cell snowflake yeast clusters initially have a low probability of forming their own propagules, but mutant-only propagules are eventually assured.