Controversial American scientist James Watson, who is one of the co-discoverers of DNA structure, has died at 97, the Cold Spring Harbor Laboratory (CSHL) confirmed on Friday.

“Jim Watson made many contributions to science, education, public service, and especially Cold Spring Harbor Laboratory (CSHL),” the laboratory said in a statement.

Mr Watson made one of the most important discoveries of the 20th century when he first identified the double-helix structure of DNA in 1953 alongside British scientist Francis Crick.

The discovery, which earned him the 1962 Nobel Prize in Physiology or Medicine with Maurice Wilkins and Mr Crick, led to rapid advances in molecular biology.

However, Mr Watson’s reputation suffered a significant damage when he claimed that genes caused a difference in average IQ between black and white people during a television appearance in 2007.

“I am inherently gloomy about the prospect of Africa because all our social policies are based on the fact that their intelligence is the same as ours — whereas all the testing says not really,” Mr Watson said.

He added, “There is no firm reason to anticipate that the intellectual capacities of peoples geographically separated in their evolution should prove to have evolved identically.”

The comments led to him losing his job as chancellor at CSHL in New York before being stripped of his honorary titles by the laboratory in 2019 following additional claims about race and intelligence.

“Dr Watson’s statements are reprehensible, unsupported by science,” the laboratory said in a statement after the 2019 comments.