In 1933, Thomas Hunt Morgan, an American of partly Scottish
ancestry, was awarded a Nobel prize for discovering the functions of
chromosomes in heredity.
In 1944, a paper was published at Rockefeller University in
New York City. This paper proved that genes are comprised of a substance
called Deoxyribonucleic acid (DNA). Two of the three authors , Dr. Maclyn
McCarty and Dr. Colin Munro Macleod, had Scottish backgrounds.
Arguably the century's most important advance in medical
science was working out the structure of DNA. The Double Helix was
co-discovered by a Scottish American, Dr. James D. Watson. In 1988, Dr. Watson
became the first Director of human genome research at the National Institute
of Health.