Biochemist and Noble laureate Arthur Kornberg died on Friday; he was 89. Kornberg won the Nobel Prize in medicine for discovering DNA polymerase, as well as was the first to produce the active inner core of a virus in the lab. His passion for enzymology and faith that all metabolic reactions could be reproduced in a test tube helped birth the field of genetic engineering. His son, Roger, also won the Nobel in 2006, making Kornberg one of only six Nobel laureates whose sons also won Nobel Prizes.