||Fromm et al. A Uniform System for the Annotation of Vertebrate microRNA Genes and the Evolution of the Human microRNAome. Annu Rev Genet. 201549:213-42. doi: 10.1146/annurev-genet-120213-092023 p.224 3rd paragraph & p.225 figure 5 number '39' in parentheses in bottom-most nodePubMed ID26473382
|| Hertel J, Lindemeyer M, Missal K, Fried C, Tanzer A, et al. 2006. The expansion of the metazoan microRNA repertoire. BMC Genomics 7:25 DOI: 10.1186/1471-2164-7-25  Prochnik SE, Rokhsar DS, Aboobaker AA. 2007. Evidence for a microRNA expansion in the bilaterian ancestor. Dev. Genes Evol. 217:73–77 DOI: 10.1007/s00427-006-0116-1  Sempere LF, Cole CN, McPeek MA, Peterson KJ. 2006. The phylogenetic distribution of metazoan microRNAs: insights into evolutionary complexity and constraint. J. Exp. Zool. Mol. Dev. Evol. 306B:575–88 DOI: 10.1002/jez.b.21118PubMed ID16480513, 17103184, 16838302
||P.224 3rd paragraph: "This continuous acquisition of miRNA genes was punctuated by several instances of elevated rates of miRNA innovation (ref 13). When taking all of these animals into account (ref 144), the four largest increases in miRNA innovation occurred along the lineage leading to humans (Figure 5, events 1–4). The first substantial gain occurred in the bilaterian ancestor of protostomes and deuterostomes (event 1), with the gain of 32 families and at least 39 genes (primary sources). The second occurred at the base of the vertebrate lineage (refs 63, 64, primary source 67), with the acquisition of 45 new families and 176 genes (event 2). The third increase occurred at the base of eutherian mammals (primary source 67, refs 73, 102), with the evolution of 91 new miRNA families and 144 genes (event 3). The final dramatic increase occurred in the lineage leading to human, after it split from mouse (refs 73, 102), with a gain of 111 families and 179 genes (event 4)." Updated annotation from Fromm et al (2015). Note from Prof Peterson [last author name on Fromm reference article] on Jan 2nd 2018: "We had 39 reconstructed at the time, but I have been able to homologize paralogues in two additional families, bringing the total to 41. " See link for a list of all 41 conserved miRNA genes.
||Kevin J Peterson