FIGURE S1. Distinguishing between types of chromosome IV LOH events in the
MHM strain. Phenotypes were determined for both halves of red half-sectored colonies.
Analysis of the URA3 marker in the white half of the colony was used to determine
whether LOH events at SAM2 were reciprocal (A) or non-reciprocal (B). The red half of
the colony was always Ade- and Ura+. A) Following a reciprocal LOH event (due to a
crossover), the white half of the colony is Ura-. B) The white half of the colony resulting
from a non-reciprocal LOH event is Ura+. Analysis of distal markers, by growth
phenotype on media containing hygromycin and clonNAT, was used to distinguish
between local LOH events (local gene conversion) and multi-locus LOH events (BIR,
non-disjunction or chromosome truncation). The red half of a colony resulting from a
local gene conversion LOH event is NatR and HygR, whereas in any other non-reciprocal
LOH it is NatR and HygS.