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. Author manuscript; available in PMC: 2010 Feb 1.
Published in final edited form as: Dev Biol. 2008 Nov 19;326(1):201–211. doi: 10.1016/j.ydbio.2008.11.008

Fig. 2. Overnight heat treatment reliably induces midline bifurcations in MZsqt embryos.

Fig. 2

(A–C) Embryonic phenotypes after overnight heat treatment. Overnight (22h) heat treatment caused no significant defect in WT embryos (A), but led to the MB phenotype in a fraction of MZsqt embryos from every cross tested. Severe MBs extended from the trunk to the hindbrain, as demarcated by the otic vesicles (arrows) (B). Weaker MBs were limited to the trunk (C). Arrows point to otic vesicles. (D–E) Overnight heat treatment increases MB incidence in MZsqt embryos. WT and MZsqthi975/hi975 (D) or MZsqtcz35/cz35 (E) embryos were cultured under standard conditions (28°C) or heated (34°C) overnight starting at the 64-cell stage, then scored for the MB phenotype on 1 day post fertilization. A significant difference was observed between control and heated MZsqthi975/hi975 embryos (p=3.00E-08), or control and heated MZsqtcz35/cz35 embryos (p=0.00126). (F) Early initiation of heat treatment is required to induce MB. MZsqt embryos pooled from several crosses were heated overnight, beginning at the indicated stages and scored for the MB phenotype on 1 day post-fertilization. Numbers of embryos scored are shown. Percentages for each phenotype are indicated: normal appearing (white); cyclopia alone (green); MB alone (red) and MB + cyclopia (yellow).