INHERITANCE AND ALTERATION OF TRANSFORMING DNA DURING AN INDUCED PARASEXUAL CYCLE IN THE IMPERFECT FUNGUS CLADOSPORIUM-FULVUM

Protoplasts of a pAN7-1 -transformed isolate of Cladosporium fulvum race 4, harbouring a tandem duplication of the vector, and an untransformed race 5 isolate were fused, without selection for the presence of vector sequences. Fusion products were allowed to haploidize spontaneously. The inheritance of pAN7-1 sequences and the expression of the hph gene was studied in 8 5 progeny. A very high proportion (80 %) of the progeny contained vector sequences and 70 % of the progeny were resistant to hygromycin. Inactivation of the hph gene occurred in eight progeny. Rearrangement of vector sequences can account for the inactivation: there is no evidence for any RIP-like mechanism. A number of novel bands were observed.