Xenbase Image ID: 140104

Fig. 1. Organ situs in singletons and conjoined twins can be disrupted by treatments that affect the primary organizer. (A) The wildtype placement of three organs is shown: the heart with the apex on the animal’s right (red arrowhead), the stomach with the coil ending on the animal’s left (yellow arrowhead), and the gall bladder, positioned on the top of the stomach on the animal’s right (green arrowhead). Several examples of heterotaxia are also shown, with individual organs mirrored. (B) Examples of heart situs in conjoined twins. Both hearts are examined, but because the left twin is the induced one, only its situs (outlined in yellow) reveals the effects of a treatment on a late-induced organizer. The heart of the primary twin (outlined in blue) can be randomized due to leaky morphogens from the left-sided twin (Levin et al., 1996; Levin and Nascone, 1997; Nascone and Mercola, 1997). Wildtype heart situs is indicated by an orange arrowhead; inverted heart situs is indicated by a white arrowhead. All panels show tadpoles (singletons and conjoined twins) from a ventral view, with anterior pointing upward. Image published in: Vandenberg LN et al. (2014) Copyright © 2014. Reproduced with permission of the Publisher, University of the Basque Country Press. Larger Image Printer Friendly View

Return to previous page