GENETIC AND MOLECULAR ANALYSIS OF ASPERGILLUS-NIDULANS TRANSFORMANTS OBTAINED BY THE BIOLISTIC PROCESS

Twenty transformants obtained by transforming the argB strain of Asper gillus nidulans by the biolistic process were analysed in detail. Eigh t lost the Arg(+) phenotype very frequently and the other 12 were mito tically stable, even after 15 successive subculturing. To analyse the integration events, the mitotically stable transformants were submited to genetic and molecular analyses; 16.7% resulted from the integratio n of the transforming DNA in tandem with the chromosomal argB locus, 8 .3% showed replacement of the argB mutation by wild type allele, 41.7% showed transforming DNA integrated into nonhomologous chromosomal reg ions at chromosome III, and 33.3% showed transforming DNA integrated i nto nonhomologous chromosomal regions al chromosomes others than III. Among the mitotically stable transformants, the frequency of integrati on into nonhomologous sites was higher by the biolistic process than t hat reported by the Literature for protoplast-mediated transformation.