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Among the non-coding DNA that composes a large percentage of the genomes of humans and other eukaryotic organisms, pseudogenes are genes that were once active but were rendered defunct by mutations at some point in evolutionary history. But some pseudogenes may regain their functionality. A study published in PLoS Genetics last week revealed that a gene that codes for a member of the immunity-related GTPase protein family, IRGM, was subject to a frameshift mutation in an ancestor of primates 40 million years ago, due to insertion of a small fragment of DNA. The non-functional pseudogene remained in the genome for 25 million years–until an endogenous retrovirus (ERV) inserted itself at the head of the gene, effectively undoing the effects of the original frameshift mutation. Said ScienceBlogger Ed Yong of the gene, “A fall from grace, a tragic demise and an last-minute resurrection – what more could you ask for from a story?”

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