PAL-1 antibodies detect PAL-1 in all cells of the two-cell (50% penetrance), four-cell (100% penetrance), eight-cell (100% penetrance), and 22-26 cell (90% penetrance) stage embryos, as opposed to just the posterior blastomeres as in wild type animals
Any variation that results in the detection of protein expression in cells/tissues through antibody staining, that is otherwise not observed in control animals.