Embryos undergo extensive DNA replication without nuclear division and form a fused giant polyploid nuclei from the male and female pronuclei and from the polar body nuclei.

Unfertilised eggs from a homozygous mother initiate DNA replication inappropriately and in fertilised eggs DNA replication is uncoupled from nuclear division, both unfertilised and fertilised eggs have one giant polyploid nuclei. Chromosomes in the embryos are never condensed and do not appear polytene. Premature replication begins at the earliest during passage into the uterus. Transheterozygotes with plu² produce a few viable adult progeny.