Figure 1.

Evolution of gluconeogenesis and trehaloneogenesis (A) Sugar biosynthetic pathways: only the steps of the pathway involving enzymes specific for gluconeogenesis and trehaloneogenesis are shown. Gluconeogenic substrates are shown in red. (B) Presence (+) or absence of key enzymes for gluconeogenesis and trehaloneogenesis across different phyla/animal groups. Boxed area highlights phyla/subphyla in which some species contain both the trehalo- and gluco-neogenic enzymes. Ch indicates subphyla belonging to the phyla of Chordata.