The Human Genome Project (HGP) was the international, collaborative
research program whose goal was the complete mapping and understanding
of all the genes of human beings. All our genes together are known as
our "genome."
The HGP was the natural culmination of the history of genetics
research. In 1911, Alfred Sturtevant, then an undergraduate researcher
in the laboratory of Thomas Hunt Morgan, realized that he could - and
had to, in order to manage his data - map the locations of the fruit fly
(Drosophila melanogaster) genes whose mutations the Morgan
laboratory was tracking over generations. Sturtevant's very first gene
map can be likened to the Wright brothers' first flight at Kitty Hawk.
In turn, the Human Genome Project can be compared to the Apollo program
bringing humanity to the moon.
The hereditary material of all multi-cellular organisms is the famous
double helix of deoxyribonucleic acid (DNA), which contains all of our
genes. DNA, in turn, is made up of four chemical bases, pairs of which
form the "rungs" of the twisted, ladder-shaped DNA molecules. All genes
are made up of stretches of these four bases, arranged in different ways
and in different lengths. HGP researchers have deciphered the human
genome in three major ways: determining the order, or "sequence," of all
the bases in our genome's DNA; making maps that show the locations of
genes for major sections of all our chromosomes; and producing what are
called linkage maps, complex versions of the type originated in early Drosophila research, through which inherited traits (such as those for genetic disease) can be tracked over generations.
The HGP has revealed that there are probably about 20,500 human
genes. The completed human sequence can now identify their locations.
This ultimate product of the HGP has given the world a resource of
detailed information about the structure, organization and function of
the complete set of human genes. This information can be thought of as
the basic set of inheritable "instructions" for the development and
function of a human being.
The International Human Genome Sequencing Consortium published the first draft of the human genome in the journal Nature
in February 2001 with the sequence of the entire genome's three billion
base pairs some 90 percent complete. A startling finding of this first
draft was that the number of human genes appeared to be significantly
fewer than previous estimates, which ranged from 50,000 genes to as many
as 140,000.The full sequence was completed and published in April 2003.
Upon publication of the majority of the genome in February 2001,
Francis Collins, the director of NHGRI, noted that the genome could be
thought of in terms of a book with multiple uses: "It's a history book -
a narrative of the journey of our species through time. It's a shop
manual, with an incredibly detailed blueprint for building every human
cell. And it's a transformative textbook of medicine, with insights that
will give health care providers immense new powers to treat, prevent
and cure disease."
The tools created through the HGP also continue to inform efforts to
characterize the entire genomes of several other organisms used
extensively in biological research, such as mice, fruit flies and
flatworms. These efforts support each other, because most organisms have
many similar, or "homologous," genes with similar functions. Therefore,
the identification of the sequence or function of a gene in a model
organism, for example, the roundworm C. elegans, has the
potential to explain a homologous gene in human beings, or in one of the
other model organisms. These ambitious goals required and will continue
to demand a variety of new technologies that have made it possible to
relatively rapidly construct a first draft of the human genome and to
continue to refine that draft. These techniques include:
- DNA Sequencing
- The Employment of Restriction Fragment-Length Polymorphisms (RFLP)
- Yeast Artificial Chromosomes (YAC)
- Bacterial Artificial Chromosomes (BAC) The Polymerase Chain Reaction (PCR)
- Electrophoresis
Of course, information is only as good as the ability to use it.
Therefore, advanced methods for widely disseminating the information
generated by the HGP to scientists, physicians and others, is necessary
in order to ensure the most rapid application of research results for
the benefit of humanity. Biomedical technology and research are
particular beneficiaries of the HGP.
However, the momentous implications for individuals and society for
possessing the detailed genetic information made possible by the HGP
were recognized from the outset. Another major component of the HGP -
and an ongoing component of NHGRI - is therefore devoted to the analysis
of the ethical, legal and social implications (ELSI) of our newfound
genetic knowledge, and the subsequent development of policy options for
public consideration.
By
Vinesh S
By
Vinesh S
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