Human Genome Project
Identifying genes associated with disease--indeed, tracking down every chemical base in each of the estimated 25,000 genes as well as the spaces between them, a process called mapping the human genome--has been accomplished successfully by an international collaboration known as the Human Genome Project.
Scientists have developed a consensus sequence, laying out the order in which all the human genes sit along the chromosomes. This information can be used to determine where gene mutations occur in specific diseases. For example, here is a chart of disease-linked genes located along the X chromosome.