Mario Capecchi has made numerous outstanding contributions to the understanding of genetics, particularly in the area of gene expression. Capecchi is noted for establishing a method to inactivate target genes in mice and successfully breeding these "knocked-out" mice to study gene functions. Researchers throughout the world use this methodology, and its application has benefited many other areas of science. Capecchi has also contributed significant research to the field of gene expression. In his early career, Capecchi worked out the mechanisms of chain termination in protein synthesis and developed methods for gene replacement. These areas of research have greatly expanded knowledge of the relationship between genes and phenotype.

Capecchi was born in Verona, Italy in 1937. He immigrated to the United States and received his Bachelor of Science degree at Antioch College. He then went to Harvard University and finished his Doctoral degree in 1967. After graduation, he became an assistant...