Denton Cooley 1960s. He and his colleagues worked on developing new artificial heart valves from 1962 to 1967; during that period, mortality for heart valve transplants fell from 70% to 8%. In 1969, he became the first heart surgeon to implant an artificial heart designed by Domingo Liotta in a man, Haskell Karp, who lived for 65 hours. The next year, in 1970, "he performed the first implantation of an artificial heart in a human when no heart replacement was immediately available." Cooley's interests included basketball, which he played in high school and as a three-year letterman for the UT men's basketball
Human artificial chromosome by these vectors not only leads to different expression levels, but the inserts also disrupt the original genome. HACs differ in this regard, as they are entirely separate chromosomes. This separation from existing genetic material assumes that no insertional mutants would arise. This stability and accuracy makes HACs preferable to other methods such as viral vectors, YACs and BACs. HACs allow for delivery of more DNA (including promoters and copy-number variation) than is possible with viral vectors. Yeast artificial chromosomes and bacterial artificial chromosomes were created before human artificial chromosomes, which first appeared in 1997. HACs are useful in expression