Synteny of pancreatic lipase genes (light yellow) in mammals and fishes. The conserved neighborhood genes (pitx3 and hspa12a) were marked with gray. The pseudogenes were marked with a red slash.

Synteny of bile salt-activated lipase genes (light yellow) in mammals and fishes. The conserved neighborhood genes (gtf3c5) were marked with green. The pseudogene was marked with a red slash.

Phylogenetic relationship of pancreatic lipase genes in mammals and fishes with based on the ML method. The bootstrap test (1000 replicates) scores are shown with numbers. The blackline represents the group of PL genes in mammals, the red line represents the first group of pl genes in fishes, and the blue line represents the second group of pl genes in most of the fishes.

Phylogenetic relationship of bile salt-activated lipase genes in mammals and fishes with based on the ML method. The bootstrap test (1000 replicates) scores are shown with numbers. The black line represents the group of BSAL genes in mammals. The fish bsal genes whose neighborhood gene was conserved were shown with the blue line, the other bsal copies were shown with the red line.

Partial amino acid sequence alignments of pancreatic lipases for humans and fishes. Boxes in green and yellow represent the lid domain and β-9 loop of pancreatic lipase, respectively. Active site triad residues Ser, Asp, and His were marked with pink. The red and blue boxes represent the absence of Ile and Leu in the lid domain and β-9 loop, respectively. The dashes (-) represent gaps found upon sequence alignment. Numbers refer to the amino acid were located at the end of each line.

Partial Amino acid sequence alignments of bile salt-activated lipases for humans and fishes. (A) The correct amino acid residues of the bile salt-binding site (GANFLXNYLY) were marked with green, and other types of amino acid residues in the bile salt-binding site were marked with red. (B) Active site triad residues Ser, Asp, and His were marked with pink. The dashes (-) represent gaps found upon sequence alignment. Numbers refer to the amino acid were located at the end of each line.

3D structures of pancreatic lipase in human, mouse, and partial fish species. The lid domain and β-9 loop of pancreatic lipase were marked with green and yellow, respectively. The regions of Ile and Leu (or replaced by other amino acids) in the lid domain and β-9 loop were marked with red and blue, respectively. Active site triad residues Ser, Asp, and His were marked with pink.

3D structures of bile salt-activated lipases in human and partial fish species. The region of amino acid residues in the bile salt-binding site (GANFLXNYLY) was marked with green. Active site triad residues Ser, Asp, and His were marked with pink. The red arrow represents the no loop structure that existed in mandarin fish (H).

Abridged general view of digestive lipases during the evolution among mammals and fishes. The vertebrate ancestor might have one pl gene and 1 bsal gene, the fish ancestor retained the one pl gene and one bsal gene, then fish ancestor divided into three groups, the first group lost the pl gene but had two to three bsal gene copies (group 1), the second group had one pl gene and had two to five bsal gene copies (group 2), the third group retained the one pl, and 1 bsal (group 3). The common ancestor of mammals obtained other PL gene copies but retained one BSAL gene.