hb, kni double mutants show reduced rate of germ band extension. Cell intercalation is reduced in the region where the germ band fails to narrow, i.e. the region where eve and other pair-rule gene expression is uniform.
kni10 hb4 double mutant embryos fail to undergo normal germ band extension.
Premature reduction of gt protein in the posterior domain. In the head region the middle stripe persists as an unbroken band covering the entire ventral side.
Posterior gt expression domain fails to narrow completely to a stripe during cellularization.