On their own, many cryptic mutations may not amount to much, but together they can allow organisms to adapt quickly to new circumstances, says Ed Yong at Scientific American.
For example, he points to small, seemingly neutral mutations to neuraminidase in the influenza virus that, in conjunction with a H274Y mutation to that protein, allows the virus to evade the effects of Tamiflu.
"Both mutations looked innocuous individually, but together they made the virus more adaptable in the face of a challenge," Yong writes. "To put it another way, they made it better at evolving."
He adds that such mutations could play a role in a number of traits, from height to schizophrenia, where genes have been associated, but that also suffer from apparent levels of 'missing heritability.' "This is just wild speculation on my part, but it sounds reasonable to me," the University of Pennsylvania's Joshua Plotkin tells Yong.