Psc¹⁵ embryos from heterozygous mothers show segregation defects in anaphase and telophase as judged by the presence of chromatin bridges. Most of these chromatin bridges are probably resolved because large irregularly-shaped nuclei and polyploid nuclei are only seen at a low penetrance. Psc¹⁵ embryos also show a higher level of "nuclear fallout", a process that removes nuclei with abnormal mitoses, than wild-type embryos. Fallout nuclei tend to be observed in pairs or clusters and have a late telophase appearance. There is no evidence of metaphase defects in these embryos although a small number show chromatin bridges that persist to the prometaphase stage.