Washington: Practice makes perfect in music, but fresh evidence thrown up by research shows that for aspiring musicians, genes may also influence the outcome.

Perfect pitch, also known as absolute pitch, is the rare ability to recognise and name musical notes without any reference pitch for comparison, detecting, for instance, A before middle C.

The rarity of the aptitude contrasts with the common ability to immediately recognise and name colours, distinguishing pink from red or azure from blue.

University of California - San Francisco (UCSF) scientists said they identified a particular region of genes on human chromosome eight that is linked to perfect pitch, at least in people of European ancestry. The next step, they say, is to identify a specific gene.

The finding, part of a larger examination of families of various ancestries, Europeans, Ashkenazi Jews, Indians and East Asians, is the first significant genetic evidence of a role of genes in perfect pitch.

It is likely, the researchers say, that multiple genes are involved in all cases of perfect pitch and that different genes could be associated with different ethnic backgrounds.

Regardless, the finding is an important advance, they say, in their effort to move in on the relative roles of early musical training and genetic inheritance on perfect pitch.

More broadly, says senior study co-author Jane Gitschier, professor of medicine, paediatrics and genetics, and herself a singer, it is an advance in the team's effort to explore the relative contributions of environmental factors and genes on learning and other behaviours.

"Perfect pitch is a window into the way in which multiple genes and environmental factors influence cognitive or behavioural traits," she says.

The team has learned over the last decade that both factors contribute to perfect pitch. "What's exciting now," she says, "is that we now have made the first foray into teasing out the genes that may be involved."

In the current study, the team drew on data acquired from the lab's web-based survey, established in 2003, which gathers information about participants' musical training history and tests their pitch-naming abilities, said an UCSF release.

These findings were published in the Friday online edition of the American Journal of Human Genetics.