Biophysical and genetic evidence for transformation in plants.

In thiamine mutants of Arabiodopsis, genetic corrections have been obtained by treatment with DNA bearing a thiamine information. When correction is attempted under selective conditions, about 0.7% of the treated plants grow and set fruit. Their progeny and the following ones, obtained by selfing, behave as homozygotes. Segregation of characters is found only when correction is attempted under nonselective conditions or when the correcting genes were of plasmidian origin. The correction is hereditary; results of backcrosses and test crosses indicate that it is dominant, nuclear, and strongly bound to the genome. The corrective factor appears to be added to the mutated genome and not substituted for the mutation, as it can be suppressed by outcrossing with the wild type or with a plant corrected by another DNA.