Comparative genomics reveals a close relationship between A. flavus and A. oryzae as their genome sizes (A. flavus 36.8 and 12,197 genes; A. oryzae 36.7 Mb and 12,079 genes), and the number of orthologous genes is very high.
Thus, each species has only about 350 unique genes.
These facts led to the assumption that the two fungi might even be ecotypes of the same species and that the domestication of A. flavus resulted in A. oryzae (Payne et al. 2006).
This domesticated form has been used for centuries in the Asian fermentation industries, e.g., soy sauce, sake, and vinegar.