Prior to the initiation of the HGP, it was thought that there were about 100,000 genes in the chromosomes. The HGP found there were maybe as few as 30,000 . These instructions are codes in strands of DNA that signal for the production of amino acids, which are the building blocks of humans. As we learn more about the human genome, we will unlock many of the secrets of life. The ultimate goal is to prevent, treat, and cure the myriad diseases that afflict humankind.
Genetic factors play a role in most diseases.
Examples of disorders that are completely on a genetic basis are Down syndrome, resulting from an extra copy of chromosome 21, and cystic fibrosis, from a mutation on chromosome seven. Multiple genes influence the development of diseases such as hypertension, diabetes, Alzheimer's disease, Parkinson's disease, many psychiatric disorders, deafness, rheumatoid arthritis, and some forms of cancer. The practice of medicine of the future largely will be at the molecular level. The medicine of today will be thought comparable to the use of leeches and purgatives in the time of George Washington. Basic gene research should provide the guideposts for the diagnosis, prevention, and cure of most or all diseases .