Figure 7.

Evolutionary scenario of gallbladder loss in the rat. The schemes for zebrafish and Xenopus are drawn after Shin et al. (2012) and Zorn & Mason (2001), respectively. An obvious hepatic diverticulum is found in the ventral foregut in the rat, as seen in many other vertebrates. However, the SOX17‐positive biliary bud is completely lost in rats, while Sox17 is expressed in other animals that have gallbladders. bil, biliary bud; cd, cystic duct; chd, common hepatic duct; dpb, dorsal pancreatic bud; duo, duodenum; gb, gallbladder; pc, pancreas; vpb, ventral pancreatic bud. [Correction added on 24 October 2017, after first online publication: the abbreviations cited on this figure was added on figure caption]