Yeast proteome. Researcher's hand holding a tray containing part of the yeast (Saccharomyces cerevisiae) proteome. This is the complete set of proteins that makes up an organism. The proteome is complementary to the genome, which is the sequence of all the genes in an organism. Genes, specific lengths of DNA, are biochemical instructions for the manufacture of proteins. Proteins form the vast majority of the structures in an organism. Proteomics, the study of the structure and function of proteins, provides much information about how an organism works. Photo- graphed at the Harvard Institute of Proteomics at Harvard University, Massachusetts, USA.