Use of homologous amdS genes as selectable markers

A DNA sequence encoding an acetamidase which comprises an amino acid sequence which is characterized in that:

• a) its amino acid positional identity with one of the amino acid sequences of SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, and SEQ ID NO:5 is more than 30%, and
• b) its amino acid positional identity with each of the amino acid sequences of SEQ ID NO:1, SEQ ID NO:2, and SEQ ID NO:3 is less than 100%.

A living cell selected from the group consisting of fungi from the Aspergillus niger group, the Aspergillus glaucus group, the Aspergillus terreus group, the Aspergillus restrictus group, the Aspergillus fumigatus group, the Aspergillus cervinus group, the Aspergillus ornatus group, the Aspergillus clavatus group, the Aspergillus versicolor group, the Aspergillus ustus group, the Aspergillus wentii group, the Aspergillus ochraceus group, the Aspergillus candidus group, the Aspergillus cremeus group, the Aspergillus sparsus group, Penicillium species, Trichoderma species, Mucor species, Rhizopus species, Phanerochaete species, Neurospora species, Humicola species, Claviceps species, Sordaria species, Ustilago species, Fusarium species, Schizophyllum species, Cephalosporium species, Acremonium species, edible fungi of which preferably Agaricus bisporus, Kluyveromyces species, Yarrowia species, Candida species, Hansenula species, Pichia species and Phaffia species, characterized by their ability to grow well on a culture medium containing acetamide as sole carbon and/or nitrogen source and wherein said ability is not caused by the expression of a heterologous acetamidase gene.