UCSF scientists are using the Internet to collect data and make a pitch for musically gifted research subjects who may help yield insight to a classic nature-versus-nurture question.

The Neurogenetics Laboratory has put up a website that could speed its search for a gene, or set of genes, involved in the ability to recognize or play a specific musical note without hearing a reference note. Only an estimated one in 2,000 in the general population -- and 15 percent of musicians, according to a preliminary UCSF study -- has this gift, called perfect pitch. But is this talent learned or inherited?

Musicians, especially those who believe they and family members have perfect pitch, can tune into the new site and play a role in answering that question. A survey, which takes two minutes to complete, asks musical background information. Musicians who can fiddle with a computer and have the proper software may then take an auditory exam, which tests their ability to identify pure and piano tones. Those with absolute or perfect pitch may be telephoned for another test and eventually asked for blood samples, which will help the lab hone in on a perfect pitch gene.

The study was started two years ago by music lovers and renowned geneticists Jane Gitschier and Nelson Freimer, who hypothesized that having perfect pitch may be a matter of both genetics and environment (see previous Daybreak story). Their preliminary study, published in the Feb. 1 issue of “American Journal for Human Genetics” and reviewed in “Nature/Genetics,” suggests that one inherits a predisposition for the talent, but it must be exercised early in life in order for it to be realized.

The survey of 612 professional and student musicians found that 40 percent of those who began formal musical training by age four reported developing perfect pitch. In contrast, only four percent of those who began training after age nine did. The decline in between was remarkably steady. At the same time, the study found that those with perfect pitch were four times more likely to have a family member with perfect pitch than those without it. Forty-eight percent of those with perfect pitch said they had a first-degree relative with the skill, while only 14 percent of those without perfect pitch did.

While the data are important, they are only the first part of what could lead to a major scientific score. Siamek Baharloo, a graduate student in Freimer’s lab, gathered that information by surveying music students from around the country. He also performed auditory tests using a laptop computer, and even drew blood from willing research participants. The new website will not only cut down the amount of leg work, but also help attract the larger number of research subjects -- both to participate in the survey and to have their DNA sampled -- required to make it a sound study.

So far, UCSF has some 90 musicians for DNA studies, but the lab hopes to at least double that figure, said Baharloo.

Although the website has been up for only two weeks and has not yet been promoted widely, more than 40 people, some from as far away as Europe, have participated, said Baharloo.

The study, while interesting in itself, also identifies perfect pitch as a model trait for exploring the relative roles of "nature and nurture" in human behavior, says Gitschier.

Although much is known about the anatomy and physiology of the human auditory pathway, the specific neural mechanisms involved in pitch perception remain unclear. Psychophysical and physiological experiments suggest that high-level brain processes are involved, but there is no evidence regarding underlying developmental mechanisms that may play a roles in these processes.

Previous studies of the aptitude have been small and have investigated either genetic or environmental influences, identifying compelling evidence in both. The UCSF investigation is the first large-scale study to examine both factors.

Much of the study, like other genetics investigations, will focus on Ashkenazi Jews, descendants of a relatively small number of families in Central and Eastern Europe. Because until recently these people did not often intermarry with other groups, those individuals with a given trait such as perfect pitch have probably inherited it in common from a few ancestors, says Freimer, making them ideal for identifying genes for human traits.

"Whatever genetic predisposition there is for perfect pitch, it is likely that it will be identical in a majority of Ashkenazi Jews," says Freimer. Ashkenazi Jews also have a b tradition of early musical training, which suggests, he says, that perfect pitch may be highly expressed in these people.

The suggestion that a specifically timed environmental influence is necessary to spark the potential of a genetic predisposition is not new. Researchers have determined that there is a critical period in the development or reinforcement of certain neural circuits in the brain for singing behavior in song birds and for language development in humans.

"It may be," says Gitschier, "that there is a developmental period for perfect pitch, during which the brains of some people are particularly amenable to establishment of new circuits or fine-tuning of pre-existing circuits involved in pitch perception."
This period parallels the stage that appears to be most critical for the development of language skills, says Baharloo.

Alternatively, says Gitschier, it is possible that individuals who are genetically predisposed to developing perfect pitch may be more likely than others to start musical training early in life. "Perfect pitch may thus be part of the general phenomenon of musicality," she says, "and an early interest in music could result from greater tonal acuity and increased awareness for sounds in predisposed children."

If this is the case, Gitschier theorizes, genetic predisposition for perfect pitch might be prompting an early interest in music, but early training would still be necessary for cultivating the skill.

Gitschier, herself a singer, has respect for the innate factor leading to perfect pitch. "I don't have even good `relative pitch,'" she says, "but I have had lots of accompanists and teachers who have it. It has always amazed me that people have this ability.

"Teasing out the roles of genes and the environmental influence is going to be a really interesting, really, really complex problem that's going to take a long time to solve," says Gitschier, "but we made a nice first pass at the problem."

By Andy Evangelista and Jennifer O’Brien

1st appeared 2/2/98

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