Culver, Billy W.Morton, Philip K.2015-04-202016-03-302015-04-202016-03-302015Billy W. Culver and Philip K. Morton, “The Evolutionary History of Daphniid α-Carbonic Anhydrase within Animalia,” International Journal of Evolutionary Biology, vol. 2015, Article ID 538918, 11 pages, 2015. doi:10.1155/2015/538918http://hdl.handle.net/11244/14436Understanding the mechanisms that drive acid-base regulation in organisms is important, especially for organisms in aquatic habitats that experience rapidly fluctuating pH conditions. Previous studies have shown that carbonic anhydrases (CAs), a family of zinc metalloenzymes, are responsible for acid-base regulation in many organisms. Through the use of phylogenetic tools, this present study attempts to elucidate the evolutionary history of the α-CA superfamily, with particular interest in the emerging model aquatic organism Daphnia pulex. We provide one of the most extensive phylogenies of the evolution of α-CAs, with the inclusion of 261 amino acid sequences across taxa ranging from Cnidarians to Homo sapiens. While the phylogeny supports most of our previous understanding on the relationship of how α-CAs have evolved, we find that, contrary to expectations, amino acid conservation with bacterial α-CAs supports the supposition that extracellular α-CAs are the ancestral state of animal α-CAs. Furthermore, we show that two cytosolic and one GPI-anchored α-CA in Daphnia genus have homologs in sister taxa that are possible candidate genes to study for acid-base regulation. In addition, we provide further support for previous findings of a high rate of gene duplication within Daphnia genus, as compared with other organisms.evolutionary biology; acid-base regulation in organisms; carbonic anhydrases; phylogenetic toolsArticlehttp://dx.doi.org/10.1155/2015/538918