Mutations arising during transformation in the blue-green alga Anacystis nidulans

Summary Genetic transformation experiments have been performed in Anacystis nidulans using donor material from two sources, namely chemically extracted DNA and extracellular nucleic acids. A high proportion of the transformants became mutant at sites which were wild type in both parental strains. Linkage was less extensive in transformation mediated by chemically extracted DNA, and this increased frequency of recombination was associated with enhanced mutation frequencies. The frequencies of recombination and mutation were varied to the same extent by changing the DNA concentration, and both processes were prevented by pretreatment of donor DNA with DNase. Mutational events are, therefore, closely associated with recombination in A. nidulans.