| The Human
Genome Project (HGP) was launched in the 1980s as an organized effort
to provide the information researchers need to understand the genetic
basis of all disease. A genome is all the genetic information that
makes an organism.
The HGP, completed in April 2003, mapped the location of each of the
genes in the human genome and sequenced--decoded--each gene's instruction.
The project was overseen by both the NIH and the Department of Energy.
Courtesy of the National Human Genome
|The HGP is like translating an entire
library of books written in a foreign language -- the genetic code.
But with the "librarys" information, researchers can
investigate just what each gene is responsible for in the human body,
and how mutations to genes cause genetic diseases. This information
may help researchers develop tests and treatments for genetic diseases,
which will reduce human suffering and add productive years to our
To study genes, researchers use a convenient way to
make many copies of a DNA
strand. They call the method "polymerase chain reaction",
known as PCR. PCR quickly multiplies DNA segments in a test tube.
Almost every researcher in this exhibit used PCR.
looking at DNA sequencing gel. Courtesy
of the National Cancer Institute.
| In PCR, researchers select which
genes they are interested in and use heat to separate the DNA strands
that encode that gene. Then, on each end of a separated strand, primers
(short strings of nucleotides)
bind to the DNA sequences which complement them. Nucleotides fill
in the middle to form a second complete DNA strand. Repeating these
steps on all of the copies creates a billion copies of the target
DNA in a few hours.
How PCR works.
Courtesy of the National Human Genome Research Institute
| A method that researchers
use to study genes and chromosomes is called "fluorescence in
situ hybridization" (FISH). This long name describes a process
which binds chemicals that are fluorescent (they glow when exposed
to a certain light) to DNA segments whose genes are known. Then researchers
can see where the genes fit in the chromosome. By using many colors
of fluorescent chemicals, a researcher can "paint" the genes
of a whole chromosome. Once a researcher knows where a certain gene
is supposed to be on a chromosome, s/he can use FISH to see if the
gene is located in the wrong place on the chromosome or is on a different
chromosome altogether. Genes that are in the wrong location may cause
a genetic disease.
the National Human Genome Research Institute