Notochord phenotype of mutants in the not, chg, mib, snw, and mgt loci (A) The notm128 phenotype first becomes apparent at 48 hpf, manifest as regions of degeneration in the notochord (middle) or the notochord and muscle (lower). (B) Wild-type 48 hour notochord under DIC optics and (C) a notm128 mutant notchord displays abnormal cellular morphology and regions of degeneration. (D) The phenotype of chgm275 mutants becomes apparent by 24 hpf. By 48 hpf the notochord cellular morphology is abnormal throughout the axis. Shown is an anterior notochord from a 48 hpf wild-type embryo (E) and a corresponding region of a chgm275 mutant notochord (F). (G) Shown is a mibm132 mutant (lower) and a wild-type sibling (upper) at 24 hpf. (H) A 24 hpf wild-type tail and (I) mibm132 mutant tail show abnormal morphology of cells in the mutant notochord. The mutation snwm454 combines two phenotypes, regions of disrupted notochord with an overall failure to form melanophores properly. (J) In a 48 hpf snwm454 mutant (lower) the lack of melanophores is especially apparent on the yolk sac and in the head. The xanthophores and iridophores and the retinal pigmented epithelium are apparently unaffected. (K) A wild-type 28 hpf notochord displays the normal scalloped notochord cell morphology. (L) Regions of the notochord in snw mutants display an unusual phenotype in which rounded cells are present instead of the normally scalloped vacuolated notochord cells. (M) By 120 hpf mgtm635 mutant embryos (lower) are severly shorter than wild-type. Additionally, the mutants have abnormal craniofacial development including reduced branchial arch development. (N) A 32 hpf wild-type notochord and (O) a mgtm635 notochord with morphologically abnormal spherical cells. Scale bars, 250 μm (A,D,G,H,J,M); 50 μm (B,E,K,N).
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