Fig. 3

Dmac-prd is expressed in stripes during embryogenesis. Expression of Dmac-prd examined by in situ hybridization. Arrows and arrowheads indicate primary and secondary stripes, respectively. Black arrows show “old” primary stripes while red arrows indicate “new” primary stripes. Black arrowheads show splitting primary stripes, and red arrowheads indicate resolved secondary stripes. a A single weak stripe in early blastoderm (black arrow). b The first stripe becomes clearly detectable (black arrow). The second stripe emerges posterior to the first stripe (red arrow). c Two broad primary stripes appear (red arrows). d A late blastoderm stage embryo. The first primary stripe remains undivided (black arrow). The second primary stripe has divided into two secondary stripes (red arrowheads). The third primary stripe is splitting (black arrowhead). The fourth primary stripe is showing up de novo (red arrow). e When the broad shallow ventral furrow appears, the first undivided stripe, four secondary stripes (red arrowheads) and a fourth primary stripe are detected (red arrow). f Fading expression is detected in the center of the newly arisen stripe (black arrowhead). g The fourth primary stripe has divided into two stripes (red arrowheads). A weak fifth stripe appears (red arrow). h During gastrulation, a total of 8 Dmac-prd stripes are detectable. Black arrowhead indicates the posterior end of the ventral furrow. Red arrow indicates the posterior-most Dmac-prd stripe. i, j As gastrulation proceeds, a 6th primary stripe arises; bilateral head lobes become visible. Red arrowheads indicate the dividing stripe. Red arrow indicates the newly emerged stripe. Red dashed line in i shows the anterior edge of the germ rudiment. k Embryo during early germ band elongation with striped Dmac-prd expression across the whole germ band. l, m Elongating embryo with faint Dmac-prd stripes in anterior segments. Posterior segments have strong striped Dmac-prd expression. n Embryo at late germ band elongation stage. Stripes have faded except for the most posterior segment (black arrow). Hint of Dmac-prd expression appears in the mandibles (red arrow). o Later embryo showing Dmac-prd expression in the head (black arrows). p–r Detailed view of stripe splitting. p A total of 7 primary stripes have developed. The first stripe remains undivided. The next 5 primary stripes have resolved to secondary stripes. The 7th primary stripe emerges from the anterior region of the posterior end of the embryo as a broad weak stripe. q Anterior striped expression fades. The expression in the center of the 7th stripe becomes fuzzy and faint. r The 7th stripe has divided into two thin secondary stripes as there is no expression in the center. All embryos are shown with anterior to the left