Figure 4.

A pseudogene should no longer be treated as a “nonfunctional” element. The critical criterion for judging whether a gene is “functional” or not is predominantly according to its encoding-protein ability. In fact, some pseudogenes harbor a complete open reading frame (ORF) to produce mRNAs. Therefore, these pseudogenes can produce proteins that exert parental gene-like or parental gene-unlike functions. In addition, a small number of pseudogenes can be transcribed as fragments of entire mRNAs, generating different peptides that can induce immune responses or cooperate with parental genes. Because pseudogenes have the potential to produce proteins, as opposed to the traditional opinions that pseudogenes are “nonfunctional”, a reasonable nomenclature is required to reidentify these special types of sequences.