The Fischer 344 (F344) rat was originally produced by Dr Maynie Rose Curtis at Columbia University in September 1920 from the 344th brother–sister mating of rats from the Fischer commercial breeder colony 1).
1)
Rao G, Boorman G. History of the F344 rat. In: Boorman G, Eustis S, Elwell M, Montgomery C, MacKenzie W, editors. Pathology of the Fischer rat. Reference and Atlas. New York: Academic Press; 1990. pp. 5–8.