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 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 single-celled …