Quirks & Quarks

How are instincts inherited? A new theory says 'epigenetics.'

Epigenetics controls how our DNA is expressed. That might be the key to developing instincts.
When sea turtles are born, they instinctively know to move towards the ocean. (AFP/Getty Images)

Have you ever wondered how sea turtles know when they're born that they have to immediately crawl toward the ocean? Or how honeybees know to dance in order to communicate? Or how a newborn dolphin immediately knows how to swim? 

People often call them instincts and say they're hardwired in the brain, but what does that actually mean? And are they really hard-wired, in that instincts are fixed, passed down from generation to generation, never taught, just always there? 

A new hypothesis in the journal, Science, suggests we should think of instincts as ancestral memories that come from learning. Dr. Gene Robinson, one of the scientists behind the hypothesis, is the director of the Carl R. Woese Institute for Genomic Biology at the University of Illinois at Urbana-Champaign.

He says the key mechanism for developing instincts that get passed down could be epigenetics, which he says, "is a change in the function or activity of aspects in the genome without a change in the DNA."

Research paper in ScienceEpigenetics and the evolution of instincts