Recently, Carvunis et al. [42] suggested a very interesting hypothesis about how novel genes arise from non-functional translated ORFs, named proto-genes, by showing that hundreds of short ORFs of proto-genes located in non-genic sequences were actually translated and might provide adaptive potential to cells in different physiological environments in Ascomycota phylogeny, including Saccharomyces cerevisiae. According to their model, the short ORFs can evolve into real functional genes through a kind of continuous evolutionary process. In that sense, long non-coding intron regions in higher eukaryotes can be a good reservoir of short and non-functional ORFs.
