Deuterostome phylogeny and components of the RA signaling pathway in deuterostomes

Copyright information:

Taken from "Retinoic acid signaling and the evolution of chordates"

International Journal of Biological Sciences 2006;2(2):38-47.

Published online 10 Apr 2006

PMCID:PMC1458431.

© Ivyspring International Publisher. This is an open access article. Reproduction is permitted for personal and noncommerical use, provided that the article is in whole, unmodified, and properly cited.

Deuterostome phylogeny. Echinoderms and hemichordates together establish the sister group of chordates. The urochordates (=tunicates) include ascidians and appendicularians. Urochordates and cephalochordates are invertebrate chordates. The vertebrates include agnathan groups (hagfish and lampreys) as well as the gnathostome chondrichthyans (cartilaginous fish), actinopterygians (ray-finned fish) and sarcopterygians (lobe-finned fish and tetrapods). Within chordates, the phylogenetic relationships between cephalochordates and urochordates and between hagfish and lampreys are still disputed and their respective positions within the tree are thus shown as polytomies. Two important events during deuterostome evolution are the origin of chordates and the origin of vertebrates. The two rounds of extensive gene duplications early during vertebrate diversification are highlighted with green boxes labeled 'R'. Components of the RA pathway in deuterostomes. Deuterostome groups, for which a whole genome sequencing (WGS) project has already been finished are indicated with a turquoise “+”, those, for which a WGS project is underway, are marked with a turquoise “(+)”. If known, the exact number of , and genes in the genome of a specific deuterostome group is indicated, the certain presence of a gene is marked with “+” and the lack of data is highlighted by “?”.