We found that khdrbs1 genes in teleost were clustered into two sub clades, as khdrbs1a and khdrbs1b. Compared to tetrapod khdrbs1 genes, khdrbs1a and khdrbs1b formed a more close branch with a sister clade spotted gar (Figure 1). Spotted gar has an important evolutionary status because it diverged from teleost before gene duplication happened in teleost (Braasch et al., 2016). Therefore, this indicated that khdrbs1a and khdrbs1b emerged simultaneously within teleost lineage, i.e., they were generated by teleost-specific genome duplication (Hoegg et al., 2004; Jaillon et al., 2004). As phylogenetics, albeit widely analyzed, may be still short of enough reliability to elucidate gene orthologous relationships due to sophisticated situations like gene loss or gene expansion in specific lineage, we thus performed a syntenic analysis among zebrafish khdrbs1, spotted gar khdrbs1a and human khdrbs1 genes, which represented teleost and tetrapod, respectively (Figure 3), to further confirm the relationship between khdrbs1a and khdrbs1b. The results revealed that the flanking genes beside both khdrbs1a and khdrbs1b could be found in the neighboring region around spotted gar and human khdrbs1, which meant that khdrbs1 in zebrafish was orthology to spotted gar and human khdrbs1 and remained an evolutionarily conserved synteny.