By searching for genetic sequences similar to regA in the burgeoning databases of genes that now exist, they found one in a unicellular alga called Chlamydomonasreinhardtii.
Organisms other than cyanobacteria, such as the alga Chlamydomonasreinhardtii, also produce hydrogen at similar rates, says Olaf Kruse of Bielefeld University in Germany, who works with the species.