What is personal genome sequencing?
The completion of the Human Genome Project was a great advance for medical research, providing us with part of the blueprint that makes us human. However, the DNA sequence produced by the Human Genome Project is not identical to yours; virtually every individual on the planet carries a unique set of variations in their DNA sequence, affecting their outward appearance, their behavior, and most importantly from a medical standpoint, their susceptibility to disease. Today, more and more people are being genetically tested for a small number of known genetic mutations that are thought to be associated with specific diseases. The availability of such genetic tests depends on the ability of scientists to link well-characterized diseases to particular genes. For conditions with specific genetic causes, such as Huntington’s disease or cystic fibrosis, these tests have proven to be relatively straightforward. In contrast, progress has been limited with respect to complex diseases, such as cancer.
Unlike currently available genetic tests that usually characterize only one gene (or even specific parts of one gene), personal genome sequencing assesses the status of all of your genes at one time, just as if a Human Genome Project were conducted specifically on you. This assessment would include genes that have been implicated in causing disease, but also genes that are not yet well understood, and other parts of your genetic makeup that may have some unknown influence on your health. As with current testing, only the information from the parts of your genome that are well understood would benefit your present health care. However, as more and more people are sequenced, scientists will be provided with a larger set of data from which to learn about the poorly understood regions of the genome and their relationships to diseases, with the potential to benefit health care consumers in the future (see Genotype and phenotype). In some ways, widespread personal genome sequencing may blur the line between medical practice and biomedical research.
Ultimately, the application of genomic information could enhance our ability to make informed and appropriate decisions regarding health care, including, for example, the treatment of specific diseases or predispositions and the choice of drugs and drug dosage. At the same time, the questions it raises, and the possible unforeseen medical and social consequences, are yet to be fully explored. This advent of “personal genetics” will bring novel challenges and extensive ELSI questions that we, as a society and as individuals, need to address.