Aspergillus niger is a cosmopolitan fungus and its spores can be found in air and soil worldwide. This saprophyte is used in food biotechnology for the production of proteins, mainly enzymes and... Show moreAspergillus niger is a cosmopolitan fungus and its spores can be found in air and soil worldwide. This saprophyte is used in food biotechnology for the production of proteins, mainly enzymes and for the production of organic acids. In the production of proteins, several problems are encountered such as repressed gene-expression, morphologic and genetic instability and undesired metabolite accumulation. To find solutions to these problems, often mutagenesis and mitotic recombination have been used, as described in this thesis. These mutations cannot simply be recombined by crosses, as Aspergillus niger is an asexual fungus. An alternative way to recombine mutations is via the parasexual cycle, also called mitotic recombination. To obtain more information of its possibilities we studied mitotic recombination of genetic markers on chromosome III. Recently the genome sequence of A. niger has been determined and this information has been linked to the genetic map. By improving the genetic map of chromosome III we were able to study crossing-over of linked markers and found that these cross-over events occurred predominantly in a small part of the chromosome. This mitotic recombination hotspot has some interesting physical features, but it remains uncertain if and which of them is responsible for the increase in crossing-over. Show less
