DNA replication

To copy DNA, the enzymes helicase (red) and polymerase (blue) are usually needed

EQUINOX GRAPHICS/SCIENCE PHOTO LIBRARY

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

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

Article amended on
24 March 2021

We clarified the role the missing proteins play in DNA replication