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Fig. 7 | BMC Evolutionary Biology

Fig. 7

From: Growth zone segmentation in the milkweed bug Oncopeltus fasciatus sheds light on the evolution of insect segmentation

Fig. 7

Segmental phenotypes following knock-down of odd (b-b″), slp (c-c″) and hh (d-d”), in early and late germband embryos stained for inv and in hatchlings. a-a” Wildtype embryos and hatchling. b In the early germband embryo odd RNAi embryos mainly display widening of inv expression in the thoracic segments, and fusion of segments in the embryonic midline. b′ In later stages, appendages are fused, and the borders of some abdominal segments are also ill-defined, sporadically fused or narrowed. In both embryonic stages, slight ectopic expression of Of-inv is seen in single cells. b″ In the odd-RNAi hatchling this phenotype causes compression of the thorax and truncated limbs. c in slp-RNAi embryos thoracic inv expression is broader in the early germband embryo, and abnormally expressed in the midline. c′ The later slp-RNAi embryo displays severe truncation of all appendages, with only limb buds of T1 and T3 remaining. In addition, we see malformation of the abdominal segment boundaries, where gaps in inv expression can be seen. The slp-RNAi embryo is also wider than WT embryos and has an apparent breakdown of midline tissues. c″ The slp-RNAi hatchlings are compressed with almost no segmental boundaries, and holes appear in the lateral parts of the embryo, where the limbs are missing. d Early hh-RNAi embryos seem to be almost completely normal, only displaying some minor head aberration. d’ Aberrations of the head are also seen in the late germband embryos which seems to lack some folds and finer details of the head structure. Abdominal segment borders are also affected, containing gaps and ectopic expression of inv in sporadic cells. d” In hatchlings, the head is greatly reduced and malformed. Segmental borders can be seen, but they are disrupted. Limbs develop normally

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