Full text loading...
Abstract
SUMMARY: Three geographical collections (isolates) of myxomycetes originally identified as Physarum flavicomum were found to be heterothallic and the clones established from each isolate were divided into two mating types. Previous studies of six isolates of P. flavicomum showed that they could be divided into three groups. Mating occurred within groups but not between groups, and within each group there were two or more mating types. When the new isolates were crossed to the original isolates, they conformed to two of these three groups. This study established the existence of multiple alleles at the incompatibility locus in group 3. Mating-type alleles of the F 1 generation of group 3 segregated in a 1:1 ratio at meiosis. Isolates belonging to group 1 were also separated from the other two groups on morphological and physiological bases. The morphological description fits that of P. rigidum more nearly than P. flavicomum and group 1 isolates were placed in the species P. rigidum. Groups 2 and 3 were separated genetically and physiologically but morphologically the separation was not distinct. These groups were referred to as P. flavicomum varieties 1 and 2.
- Accepted:
- Published Online: