engleski

Genetic duplications as a side-effect of gene replacement in yeast

Precise genetic modifications can be easily introduced in the genome of the yeast Saccharomyces cerevisiae due to efficient homologous recombination between transforming fragments and genomic DNA. We investigated the influence of short heterologies at the ends of transforming DNA on the efficiency of gene targeting and spectrum of transformation events observed. Similar inhibitory size-dependent effect of terminal heterologies was observed in both plasmid integration (ends-in recombination) and gene replacement assay (ends-out recombination) but illegitimate integrations were much more frequent in the gene replacement assay. Interestingly, only about 60 % of transformants in the ends-out assay arose by simple gene replacement, regardless to the presence of heterologous ends, whereas more complex interactions resulted in gene or whole chromosome duplications. We propose that analogous processes involving DNA fragments crated in vivo may present an important evolutionary mechanism giving rise not only to the generation of dispersed and tandem gene/segment repeats, but also to the duplications of entire chromosomes.

gene targeting; gene duplication; aneuploidy; homologous recombination; illegitimate recombination

Nagrada: "Outstanding poster presentation"