Morphological and molecular evidence that the zebrafish intestine is organized into a small and large intestine

Our genome-wide gene expression data indicate that, despite the lack of crypts, the rostral, mid, and caudal portions of the zebrafish intestine have distinct functions analogous to the mammalian small and large intestine, respectively. Organization of ridge structures represents a unique feature of zebrafish intestine, though they produce similar cross sections to mammalian intestines. Evolutionary lack of stomach, crypts, Paneth cells and submucosal glands has shaped the zebrafish intestine into a simpler but unique organ in vertebrate intestinal biology. We analyzed gene expressions in wildtype adult zebrafish (Danio rerio) intestine by dividing it into seven segments s1 to s7 (rostral to caudal). 3 to 5 replicates. 30 samples total.