On the basis of our analyses on khdrbs gene family evolution and the mainstream opinions in WGD, we propose an evolutionary model for khdrbs gene family, as depicted in Figure 11. In brief, an invertebrate khdrbs gene underwent duplication once, and one copy of the resulting genes, as exemplified by khdrbs1, remained unchanged, while the other copy underwent duplication once more, thereby creating the vertebrate khdrbs1, khdrbs2, and khdrbs3. In teleost, the khdrbs1 was further duplicated through bony fish specific WGD, forming khdrbs1a and khdrbs1b. In some species like Amazon molly, khdrbs3 is lost in a lineage-specific manner.