Phylogenetic Distribution of CMP-Neu5Ac Hydroxylase (CMAH), the Enzyme Synthetizing the Proinflammatory Human Xenoantigen Neu5Gc

Peri, Sateesh; Kulkarni, Asmita; Feyertag, Felix; Berninsone, Patricia M; Alvarez-Ponce, David

The NCBI Genome database contains the genomes of 1 monotreme, 3 marsupials, and 126 placental mammals (table 1) . We found putatively functional CMAH homologs in the genomes of all 3 marsupials and in 110 of the studied placental genomes, but none in the platypus (a monotreme). Our analyses suggest that at least ten CMAH gene loss or inactivation events occurred during mammalian evolution (mapped in fig. 4 ). Four of these events have been described previously, including one in the human lineage (Chou et al. 1998) , one in an ancestor of New World monkeys (Springer et al. 2014) , one in an ancestor of pinnipeds and musteloids (Ng et al. 2014) , and one in an ancestor of platypus. The other five events are described here for the first time, including one in an ancestor of the sperm whale (Physeter catodon), two events in bats, one in an ancestor of the white-tailed deer (Odocoileus virginianus), and another in an ancestor of the European hedgehog (Erinaceus europaeus) ( fig. 4) . Supplementary data set S3, Supplementary Material online, is a multiple sequence alignment of all mammalian vertebrates.