A new study from University of Iowa biologists finds that genes associated with a key enzyme involved in regulating metabolism in most living species has a long, murky history.

In the study, the biologists, Albert Erives, associate professor in the Department of Biology, and Oliver Vickman, the paper’s first author who graduated from Iowa in 2018, looked at the evolutionary origin of NADK, an enzyme central to metabolism of all living cells in eukaryotes, which include all living organisms other than bacteria.

The pair found that the evolutionary origin of eukaryotes’ mitochondrial NADK is not clearly from ancient bacteria.

“Instead we find that both eukaryotic genes are ancient and of unknown provenance,” Erives says. ”This result speaks to the antiquity and murky aspects of eukaryotic origins.”

The paper, titled  “Episodic evolution of a eukaryotic NADK repertoire of ancient provenance," was published online this month in the journal, PLOS One.