Trend lines of the expression levels of 'margin genes' in ERK1 and ERK2 morphants, during early developmental stages. (A,B) The relative expression (log ratio) of a number of a number of genes, selected for their described expression in the margin at the onset of epiboly, is plotted over different developmental stages in ERK1 and ERK2 morphants. The expression levels of the selected genes hardly changes in time in ERK1 morphants, whereas in ERK2 morphants the trend of the selected genes reveals a possible showed stabilization in their expression and possible subsequent recovery in time. Dotted line indicates the limits of the expression levels for the selected margin-genes in ERK1 morphants. (C,D) Trend lines for genes involved in apoptosis. Only in ERK2 morphants an increase in apoptotic genes (casp3 and casp8) was observed. Overlapping time-points are indicated in bold (30% and 80% epiboly).