The biogenesis of iron sulfur clusters has been studied most extensively in the bacteria E. coli and A. vinelandii and yeast S. cerevisiae.
Genes nested opposite the coding sequences of their host genes are very rare, and have been observed in prokaryotes, and more recently, in yeast (S. cerevisiae) and in Tetrahymena thermophila.
Mutants in the ortholog of the fission Schizosaccharomyces pombe exit mitosis normally (unlike S. cerevisiae) but are altered in septation and cytokinesis.
In attempts to generate S. cerevisiae strains that are able to ferment D-xylose the XYL1 and XYL2 genes of P. stipitis coding for the D-xylose reductase (XR) and xylitol dehydrogenase (XDH), respectively were introduced in S. cerevisiae by means of genetic engineering.