However D. hansenii has a genetic peculiarity: the calculated gene number for D. hansenii is about 1000–2000 higher than in S. cerevisiae and S. pombe, respectively. While in S. cerevisiae, the genes per kb ratio is 0.46 and the fraction of coding DNA is 0.71, in D. hansenii these values are significantly higher (at 0.57 and 0.79, respectively), which appear to be the maximal limits for a yeast genome (Sunnerhagen & Piskur 2006).