Animals die during embryonic development. In C. elegans, often assayed as refractile eggs that fail to hatch; when applied to large-scale RNAi screens in C. elegans, more than 10% of embryos die.
Seemingly unrelated variations that concurrently occur during early embryonic development compared to control animals. In C. elegans, this can include multiple pronuclei, aberrant cytoplasmic texture, decrease in overall pace of development and osmotic sensitivity.