Figure 8. Summary model of pair-rule gene expression in the Nasonia embryo.
(A) Model of register of pair-rule gene expression in the early embryo. Nv eve and Nv odd stripes are totally complementary, whereas Nv runt stripes partly overlap each of these genes at their interface. Nv hairy stripes overlap Nv eve stripes toward the anterior of each double-segment periodicity stripe. Towards the posterior of the embryo, an extended domain of low-level Nv odd expression exhibits dynamic behavior over several nuclear cycles, and stripes 4/5 of Nv eve, Nv odd, and Nv runt each differentiate during this interval. Even more posteriorly, Nv eve stripe 6 lay anterior to a continuous Nv odd cap that extends to the posterior pole of the embryo. This region is set aside for segment specification and differentiation during germ-band extension. (B) Model of register of pair-rule gene expression in the germ-band extension (late) embryo. Single-segment periodicity stripes in the germ-band-extended embryo exhibit a variation upon early gene expression patterns. Nv eve single-segment stripes are interrupted by Nv runt and then Nv odd such that Nv runt stripes follow odd-numbered Nv eve stripes, and Nv odd stripes follow even-numbered Nv eve stripes. Each of 8 Nv hairy stripes overlaps odd-numbered Nv eve stripes that derive from the anterior of Nv eve pair-rule stripes. Additional expression of several of these genes in the ventral and head domains, which appears to rely on different regulatory logic, is not shown.