Vamsi Mootha had nothing on his mind but his new job as assistant professor at the Massachusetts General Hospital. And then he got a call on his cell phone in the last week of September, and got a no strings attached offer of $500,000.

"The conversation lasted for a few minutes, but it looked like it was going on for hours," says the 33-year-old Mootha, then an assistant professor of systems biology at Harvard. "It took me some time to realise that it was not a prank call, and that I was indeed getting the MacArthur 'Genius' Award."

The call "can be life-changing, coming as it does out of the blue", says Jonathan F Fanton, president, MacArthur Foundation. "It offers highly creative women and men the gift of time and the unfettered opportunity to explore, create, and contribute."

The only condition was that he could not talk about it until the official announcement, a week later.

"I was told that if the news leaked, I would not get the grant," Mootha says. "I am not very good at keeping secrets. But this one, I kept to myself. My older brother Ravi, who had come to visit me, was about to return to Texas. I had to persuade him to stay with me till the day of the official announcement, for I wanted him to be with me on that day."

September 28, the day his enforced silence was over, he called his parents Venkataramana Rao Mootha, a doctor, and Vasantha Mootha, a homemaker, in Beaumont, Texas.

The foundation is the absolute authority in picking recipients of its annual grant. There are, Mootha points out, no nominations; the composition of the selection panel is also never revealed.

The John D and Catherine T MacArthur Foundation has been giving out the 'genius' fellowships for 24 years now, to celebrate creative and undiscovered thinkers in a wide range of fields ranging from music to magic to economics to medicine to pottery.

At least 1000 achievers come to the foundation's attention each year. As one of America's largest private philanthropic bodies, the $4 billion MacArthur Foundation has awarded over $3 billion in various kinds of grants since 1978.

The first Indian American to get the grant was the 1983 winner, A K Ramanujan, the poet who taught at the University of Chicago.

He was followed by sarod maestro Ali Akbar Khan in 1991, and pioneering MIT economist Sendhil Mullainathan in 2002, who at 29 was the youngest recipient that year.

Mootha is this year's third youngest recipient.

The 23 recipients this year include Tommie Lindsey, a high school debating coach from California; Pulitzer Prize-winning novelist Edward P Jones from Virginia; and Amy Smith, an MIT professor who received the grant for creating labour-saving technologies for use in developing countries.

The foundation noted how, early this year, Mootha and fellow researchers reported a discovery that suggests a new treatment for adult-onset diabetes following their discovery of a gene that revs up the energy-producing ability of muscle cells.

Mootha studies mitochondria, the power plants of biological cells.

He is converting the 'promise of new technologies such as genomics and proteomics into tangible, important insights regarding basic biological processes and the sources of human diseases', the foundation noted.

Mootha was also honoured for pioneering 'powerful, adaptable computational strategies for mining data collected in laboratories throughout the world, providing an efficient means to hunt down gene interactions that lead to a wide variety of diseases'.

"I do not follow the orthodox way," Mootha says, of the way he thinks and works. "The traditional way to do biology was to study one protein at a time. What these new tools allow us to do is to monitor all proteins, or all genes encoding mitochondria, in a single experiment. Genomics is sort of allowing a global biology."

Mootha was six months old when his parents migrated to America from Kakinada, in Andhra Pradesh, along with Mootha's three older siblings.

"Being the youngest has some advantages," he says. "There is far less pressure on you compared to your older siblings." The youngest can think of going into different directions than his siblings, Mootha points out.

When he was very young, he wanted to be a surgeon like his father, but in school his mathematical talent drew the attention of Beaumont professor George Berzsenyiat.

Berzsenyiat encouraged him to sharpen his math skills. 

Thus, while his own siblings pursued medicine, he went to study mathematics at Stanford University.

"I did well at Stanford and I was wondering what I should do after my graduation," Mootha recalls. His choices were a master's degree as a prelude to a career in Silicon Valley, or a move to Wall Street. What he knew for sure, by the time he was heading to complete his BS degree, was that he was not going to pursue a higher degree in math.

"I did not have the special gift like [Srinivasa] Ramanujan had," he says. "I had enjoyed a biology course I had taken at Stanford, and I decided I would be better off being a doctor or a researcher."

When he received his medical degree from Harvard, he made another big decision. Instead of preparing to practise medicine, he decided to do research. "I guess since three of my siblings --- and not to forget my father --- all practise medicine, I thought I will do something different."

Mootha, who combines clinical medicine and genomics and computing with a dedication to understanding the complex world of energy metabolism, and to work on tools to battle diabetes, says he will probably use the grant money to study rare metabolic disorders that could shed light on more common illnesses.

"I am particularly concerned about diabetes and related problems, especially in the Indian community in America," he says.

It will be a while, though, before he starts seriously planning how best to spend the grant -– he will first settle into his new teaching job.

"Right now, the impact is psychological," he says. "The grant provides me with a little more encouragement to pursue what I think is worthwhile."

Perhaps, he says, he will use some of the MacArthur grant as the seed money for his research, in the hope of attracting bigger grants.

"Five hundred thousand dollars is a very big sum of money," he says. "But when you think of the enormous time and team work required in research, you realise you need much more money."