Genetics of somatic incompatibility in Collybia fusipes

The genetics of somatic incompatibility in tetrapolar Collybia fusipes was studied using eight dikaryotic isolates collected from the wild and their e xperimentally derived progeny. Monokaryons from each isolate were all paire d with the same unrelated monokaryon and also paired together in all combin ations. The somatic compatibility of the two resulting sets of dikaryons wa s studied. Two different types of somatic incompatible interaction were obs erved, lightly or heavily pigmented lines developing between the two isolat es. The dikaryons that had one nuclear type in common and one coming from s ibling monokaryons were compatible in 7-27% of the cases, incompatible with a lightly pigmented interaction in 30-93% and incompatible with a heavily pigmented interaction in 0-53%. The results suggest that at least three to four loci control the somatic incompatibility in C. fusipes, one of them al one controlling the heavily pigmented interaction.