Toronto, Aug 5 - A gene linked to physical traits also seems to be dictating wanderlust in a tiny fish, considered a living model of Darwin's natural selection theory, according to a new study.

Measuring 3-10 cm, stickleback fish originated in the ocean but began populating freshwater bodies following the last ice age. In their new environments, these fish gradually lost their bony lateral plates, or 'armour'.

Scientists have identified a mutant form of a gene in freshwater sticklebacks that prohibits growth of armour, but is found in less than one percent of their marine counterparts.

Now Rowan Barrett and colleagues from the University of British Columbia (UBC) have found that the gene may also be contributing to the fish's tendency to relocate instead of adjusting to their surroundings.

This is the first time a gene associated with wanderlust has been identified.