many people are familiar with raga s and are able to say which musical note is being sung or played. However, not all can determine the absolute frequency at which a note is played, that is they may recognise a sa (doe) or a ma (far) but they may not be able to say which sa or ma it is. Those who do recognise the pitch fairly rapidly and state precisely which musical note is being sounded are said to possess the power of absolute pitch ( ap ).

P K Gregersen and colleagues of the Eastman School of Music, Rochester, New York, usa provide fascinating insights into this phenomenon. Based on a survey, the researchers have found that ap could be heritable, that is it may " run in the blood' ( The American Journal of Human Genetics , Vol 65).

The prevalence of ap in the general population is unknown. But it is about seven per cent among music students in general and as high as 32 per cent among Asian music students studying in the us . The nature of the institution in which the students study also play a major role. Those who attend a professional music school (a conservatory) are more likely to possess ap than those who are studying in a music programme within a university. The latter, in turn, are far more likely to possess this ability than students of music in a college. The age factor is also very important. The average age at which those who have ap started learning music is 5.4 years, while non-possessors of ap began studying music at 7.9 years.

Gregersen's team has now added a genetic aspect to this ability. It turns out that the sibling of an individual who has ap has a 14 per cent chance of developing that ability. On the other hand, the chance that a sibling of someone who does not have ap has only a 1.7 per cent chance of having ap . Similarly, parents of music students with ap have a four-fold higher chance of having ap than parents of non- ap music students. The immediate conclusion is, therefore, that ap is heritable, in the sense that it has a biological or genetic basis.

Unfortunately, the fact is that these studies are restricted to what might be called musically-sophisticated individuals. It is very difficult to disentangle the relative roles played by the genes and the environment in the individual's development. Exposure to music is fostered in musically-minded families and early exposure to music may well predispose the ability to acquire ap .

Similarly, the higher prevalence of ap in Asian students may simply mean that there is a stronger drive to learn music in Asian cultures than in European cultures. Therefore, the question must remain open for the present. Interestingly, many music students with ap report that the ability appeared spontaneously when they were very young