It is expected that by the year 2003 the entire human genome will be s
equenced, providing us with new insight into human disease. The amount
of human sequence information that is already available (only a few p
ercent of the total) is, however, already much greater than can be rou
tinely evaluated with existing, commonly used diagnostic technology. N
ew technology based on attaching DNA to a chip for parallel hybridizat
ion analysis is generating much interest in both the basic research an
d the clinical diagnostic community. It will increase, by orders of ma
gnitude, our ability to evaluate an individual's genetic heritage and
to conduct basic genetic research. The new technology will be a major
advance in screening for genetic diseases, but the ability to treat th
ese newly understood genetic defects will lag significantly behind the
new-found diagnostic capabilities.