Har Gobind Khoranaਹਰ ਗੋਬਿੰਦ ਖੁਰਾਨਾ

Har Gobind Khorana was born in Raipur, a small village in the Multan region of Punjab, in what is now Khanewal district in Pakistan. His documented birth date is 9 January 1922, though the Nobel Foundation notes that the exact date is not certain. He was the youngest of five children of Ganpatrai Khorana, a patwari, a village agricultural taxation clerk. The family was poor, but it was practically the only literate family in a village of about one hundred people, and Khorana's father was determined that his children would be educated. For his first four years of schooling, the boy was taught under the shade of a tree by a local teacher.

Education in Lahore and a doctorate in Liverpool

Khorana attended D.A.V. High School in Multan and then Government College, Lahore, before taking his BSc in 1943 and his MSc in 1945 at Punjab University, Lahore. A Government of India fellowship took him to England, where he completed a PhD at the University of Liverpool in 1948 under Roger J. S. Beer. He spent a formative year at the ETH Zurich with the great chemist Vladimir Prelog, whose rigour he credited for the rest of his life, and then worked at Cambridge from 1950 to 1952 with George Kenner and Alexander Todd. Partition had meanwhile turned his family into refugees who moved from Multan to Delhi, and Khorana, who had expected to return and serve in India, found no post waiting for him. He never lived in Punjab again.

Vancouver, Wisconsin and the race for the genetic code

In 1952 Khorana joined the British Columbia Research Council in Vancouver, where he began the work on nucleotides and coenzymes that made his name. In 1960 he moved to the Institute for Enzyme Research at the University of Wisconsin at Madison, becoming a professor of biochemistry in 1962 and an American citizen in 1966. There he joined the race to crack the genetic code: the problem of how the four letters of DNA and RNA spell out the twenty amino acids of proteins. Khorana's group built RNA chains with precisely repeated sequences, using enzymes, and showed which three-letter words, or codons, produced which amino acids. His work completed parts of the code that others could not, including the stop signals UAA, UAG and UGA that tell a cell where a protein ends.

What did Khorana win the Nobel Prize for?

In 1968 Khorana shared the Nobel Prize in Physiology or Medicine with Marshall W. Nirenberg and Robert W. Holley, in the Nobel citation's words, 'for their interpretation of the genetic code and its function in protein synthesis'. He was one of the first scientists of Punjabi birth to win a Nobel Prize. The honours that followed included the Padma Vibhushan, India's second highest civilian award, in 1969, the Lasker Award, and the United States National Medal of Science in 1987. In 1970 he moved to the Massachusetts Institute of Technology as Alfred P. Sloan Professor of Biology and Chemistry, and stayed there until his retirement in 2007.

Building the first artificial gene

Khorana's second great achievement pushed chemistry into new territory. He was the first scientist to chemically synthesise oligonucleotides, the short DNA building blocks that are now routine tools in every genetics laboratory. In the 1970s his team achieved the first total synthesis of a functional gene outside a living organism, assembling a yeast gene piece by piece and showing that it worked. That feat helped lay the foundations of genetic engineering and of the modern biotechnology industry. At MIT he later led a long programme on the chemistry and biology of vision, studying the light-sensitive proteins of the retina.

He kept a lifelong affection for the Punjab of his childhood. He followed news of the region closely, and the student exchanges run in his name were one way he stayed connected to the land where his own improbable journey had begun, with lessons under a tree in Raipur.

Family, character and legacy

Khorana married Esther Elizabeth Sibler, who was of Swiss origin, in 1952; she died in 2001. They had three children, Julia Elizabeth, Emily Anne and Dave Roy. Colleagues remembered a scientist of legendary discipline who arrived at the laboratory before dawn and demanded exactness from himself first of all. He died at Concord, Massachusetts, on 9 November 2011, aged eighty nine. The Khorana Program, founded in 2007, brings Indian science students to American universities each year in his name. His journey, from lessons under a tree in a Punjab village to a Nobel Prize, remains one of the most remarkable in modern science, and Punjab claims him, rightly, as one of its own.