Tan Jiazhen (15 September 1909 – 1 November 2008), also known as C. C. Tan, was a Chinese geneticist. He was an academician of the Chinese Academy of Sciences and a foreign member of United States National Academy of Sciences. Tan was a main founder of modern Chinese genetics.
Tan was born in Cixi, Ningbo, Zhejiang. His father was a local postman. From 1926 to 1930, Tan did his undergraduate study at Soochow University. In 1932, Tan received M.Sc from Yenching University. Tan continued his study in the United States and received PhD from the California Institute of Technology in 1937, under the supervision of Theodosius Dobzhansky. Thomas Hunt Morgan and Alfred Henry Sturtevant also were his professors. He later taught at Columbia University.
After Tan returned China, he became a professor at the Department of Biology of Zhejiang University in Hangzhou. In 1952, Tan was transferred to Fudan University in Shanghai. Tan founded the first department of genetics in China at Fudan University.
"As part of the Morgan group in the 1930s, Tan helped make Drosophila pseudoobscura the leading species for evolutionary studies and did pioneering work in insect genetics. In spite of interruptions by Lysenkoism and by the Cultural Revolution, Tan was still scientifically active in China."
Tan died on 1 November 2008 of multiple organ dysfunction syndrome at the age of 99 in Shanghai.