We know specific genes are turned on in specific cells, but we don't know to what extent this happens.

D in Physics under the mentorship of Nobel laureate Abdus Salam in 1957. He was educated at the Sidwell Friends School and attended Harvard University for undergraduate and graduate studies earning a baccalaureate in chemistry and physics in 1953 and a master's degree in physics in 1954. In 1969 he was awarded Harvard's Ledlie Prize.