Today’s bony vertebrate plin genes come from a single gene in an ancient chordate ancestor (Step 1). VGD1 (the first round of vertebrate genome duplication) produced two genes: the precursor to plin1 + plin6, and the precursor to plin2 + plin3/4/5 (Step 2). VGD2 (the second round of vertebrate genome duplication) produced four genes, plin1, plin6, plin2 and the precursor plin3/4/5 (Step 3). After VGD2, the lineage of ray fin fish, including gar and teleosts, diverged from the lineage of lobe fin fish, including coelacanth and tetrapods (Step 4), and plin6 apparently disappeared in stem lobe fins (Step 5). Before the divergence of birds and mammals, the ancestor of Plin3/4/5 duplicated to make tandem copies of Plin3 and the precursor to PLIN4/5 (Step 6). After the divergence of lineages leading to birds and mammals, the PLIN4/5 precursor duplicated in the human lineage to make tandem duplicate genes PLIN4 and PLIN5 (Step 7). Along the ray fin branch of bony vertebrates, the teleost lineage diverged from the gar lineage (Step 8) and then the TGD (teleost genome duplication) event produced copies of the four original VGD2 ohnologs, making eight plin family genes (Step 9). The ‘b’ copies of plin1, plin6, and plin3/4/5 were lost before the divergence of ostariophysans (including zebrafish) from percomorphs (including Amazon molly; Step 10). In contrast, both ‘a’ and ‘b’ copies of plin2 were retained in Amazon molly and some other percomorphs, but lost in the zebrafish lineage (Step 11).