Abstract
The results of the analysis of 393 mitotic recombinants within the paba1 region of Aspergillus nidulans can be summarized as follows:1. Reciprocal, non-reciprocal and probably inexactly reciprocal exchanges occur in intra-cistron mitotic recombination.2. Negative interference observed in intra-cistron mitotic recombination in the paba1 region of Aspergillus nidulans is more intense than that observed in meiotic recombination in the same cistron.3. In intragenic mitotic recombination multiple exchanges can involve three or even four chromatids within one effective pairing segment.