AT FIRST sight, it shouldn’t be alive: a single-celled organism that lacks most of the molecular equipment needed to copy DNA.

Duplicating DNA is fundamental to reproduction, so DNA replication systems were thought to be present in all non-parasitic species with complex cells. But it seems they aren’t.

“I was astonished,” says Dayana Salas-Leiva at Dalhousie University in Halifax, Canada. The microbe, Carpediemonas membranifera , must have a mechanism for copying its DNA that is unknown to science.

C. membranifera is a …