Abstract: The present invention relates to methods of mixing large numbers of heterologous genes, which are located on artificial chromsomes. The methods of the present invention are useful for evolution of cells and whole genomes to acquire new functionality(ies), such as the ability to synthesise novel secondary metabolites and/or the evolution of novel metabolic pathways. In particular the methods may involve mating or fusing two populations of cells, each population comprising different combinations of heterologous genes. Subsequently, desirable cells may be selected. In embodiments of the invention the heterologous genes are comprised within expression cassettes. The expression cassette can be in the form of a concatermer, and can be cut out using a restriction enzyme in order to make new combinations of expression cassettes.

Abstract: The present invention relates to the field of selecting cells producing compounds that fulfil at least 2 predetermined functionalities. The invention primarily focuses on methods for screening of cells for two or more functionalities related to small molecules generated by host cells with novel gene assemblies. The methods in one aspect of the invention are combined with methods for evolution of cells to acquire at least two predetermined functionalities related to small molecules. Furthermore, the invention relates to methods for generation of lead compounds that are selected for a primary function and at least one further secondary function. The methods according to the invention may in particular be used in high troughput screening.