Figure 7: Phylogenetic Tree of Vertebrate PTL-like and Vascular Lipase Sequences and Invertebrate Lipase Amino Acid Sequences. The tree is labeled with the lipase name and the name of the animal and is ‘rooted’ with the fruit fly (Drosophila melanogaster) lipase sequence. Note the 4 major clusters of vertebrate PTL-like sequences corresponding to the PTL, PLR1, PLR2 and PLR3 gene families and the separate cluster of vertebrate vascular lipases, divided into 3 gene families: HL (hepatic lipase); EL (endothelial lipase); and LPL (lipoprotein lipase). A genetic distance scale is shown (% amino acid substitutions). The number of times a clade (sequences common to a node or branch) occurred in the bootstrap replicates are shown. Only replicate values of 90 or more which are highly significant are shown with 100 bootstrap replicates performed in each case. A proposed sequence of gene duplication events for neutral lipase genes during invertebrate and vertebrate evolution is shown.