The Human Genome Project is a large international effort aimed at determining the sequence of the entire human genome of 3,200,000,000 base pair. But it is much more. Other aims include the creation of physical and genetic maps of the genome, sequencing the genomes of model organisms, developing technology for sequencing and informatics for understanding the sequence, training of scientists in use of these data, and exploring the ethical, legal, and social implications of the data.

The genetic and physical maps are already of great importance in research directed toward findings genes that contribute to the risk for diseases. Parallel sequencing of model organisms allows comparative studies that illuminate the potential functions of genes that are discovered. Model organisms originally targeted were E.coli, Saccharomyces cerevisiae (baker’s yeast), the nematode Caenorhabditis elegans, the fruit fly Drosophila melanogaster, and the mouse. These are key experimental organisms about which much is known. Yeast is a simple eukaryote and has been an organism of choice for studies of eukaryotic replication, repair, and recombination as well as cell cycle regulation. The nematode C. elegans is a relatively simple animal, for which the developmental fate of every cell has been mapped. Drosophila is more complex, with complex behaviors, and it has been important in genetic and developmental studies during nearly the entire 20th century. The mouse is a mammal with many similarities to us in development, physiology, and behavior. The ability to genetically engineer gene changes in mice allows us to create animal models of human disease for study. The project is well ahead of the published schedule and has expanded to include other model organisms and a search for sequence variation. Knowing the sequence of the human genome (and that of other organisms) is already having a major impact on science and medicine. But it is only the first step. Much work remains to enable us to understand the vast amounts of data generated. These data also raise issues about privacy and discrimination that need to be addressed carefully.