The co-discoverer of the double-helix shape of DNA has died, aged 97. James Watson, the American biologist whose 1953 revelation ushered in the age of genetics, died at a hospice on Long Island.

James Dewey Watson, who helped reveal DNA’s double-helix structure, kicked off the Human Genome Project, and became infamous for his racist, sexist, and otherwise offensive statements, has died. He was 97.

On a foggy Saturday morning in 1953, a tall, skinny 24-year-old man fiddled with shapes he had cut out of cardboard. They represented fragments of a DNA molecule, and young James Watson was trying to figure how they fit together in a way that let DNA do its job as the stuff of genes.

James Dewey Watson is best known for his Nobel Prize-winning discovery of the structure of DNA. Controversy around who should be credited highlights the challenges of scientific collaboration.