The Scientist reports:

Humans are still evolving new genes, according to a study published in Cell Reports on December 20. As our lineage evolved, at least 155 human genes sprung up from DNA regions previously thought of as “junk,” including two human-specific genes that emerged since humans branched off from chimpanzees around 4 to 6 million years ago, the researchers report.

“I thought it was a great study,” says Alan Saghatelian, a biologist at the Salk Institute who was not involved in the work. He adds that he “wouldn’t be surprised” if there were many more of these genes hiding in plain sight.

The genes described in the new study went undiscovered for so long because they’re teeny: They top out at about 300 nucleotides in length, while a typical human gene is 10 to 15,000 base pairs on average. Even though they possess start and stop codons that allow them to be read by cells’ transcriptional machinery just like traditional genes, these so-called microgenes—sometimes called short open reading frames (sORFs)—have long been assumed to be nonfunctional, Saghatelian explains. [Continue reading…]