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International HGP
International HGP
Initiation of the Project was the culmination of several years of work supported
by the Department of Energy, in particular a feasibility workshop in 1986 and a
subsequent initiative by the Department of Energy.[1] This 1986 report stated
boldly, "The ultimate goal of this initiative is to understand the human genome"
and "Knowledge of the human genome is as necessary to the continuing progress of
medicine and other health sciences as knowledge of human anatomy has been for
the present state of medicine." Candidate technologies were already being
considered for the proposed undertaking at least as early as 1985.[2]
James D. Watson was Head of the National Center for Human Genome Research at the
National Institutes of Health (NIH) in the United States starting from 1988.
Largely due to his disagreement with his boss, Bernadine Healy, over the issue
of patenting genes, he was forced to resign in 1992. He was replaced by Francis
Collins in April 1993, and the name of the Center was changed to the National
Human Genome Research Institute (NHGRI) in 1997.
The $3-billion project was formally founded in 1990 by the United States
Department of Energy and the U.S. National Institutes of Health, and was
expected to take 15 years. In addition to the United States, the international
consortium comprised geneticists in China, France, Germany, Japan, and the
United Kingdom.
Due to widespread international cooperation and advances in the field of
genomics (especially in sequence analysis), as well as major advances in
computing technology, a 'rough draft' of the genome was finished in 2000
(announced jointly by then US president Bill Clinton and British Prime Minister
Tony Blair on June 26, 2000).[3] Ongoing sequencing led to the announcement of
the essentially complete genome in April 2003, 2 years earlier than planned.[4]
In May 2006, another milestone was passed on the way to completion of the
project, when the sequence of the last chromosome was published in the journal
Nature.[5]
There are multiple definitions of the "complete sequence of the human genome".
According to some of these definitions, the genome has already been completely
sequenced, and according to other definitions, the genome has yet to be
completely sequenced. There have been multiple popular press articles reporting
that the genome was "complete." The genome has been completely sequenced using
the definition employed by the International Human Genome Project. A graphical
history of the human genome project shows that most of the human genome was
complete by the end of 2003. However, there are a number of regions of the human
genome that can be considered unfinished. First, the central regions of each
chromosome, known as centromeres, are highly repetitive DNA sequences that are
difficult to sequence using current technology. The centromeres are millions
(possibly tens of millions) of base pairs long, and for the most part these are
entirely unsequenced. Second, the ends of the chromosomes, called telomeres, are
also highly repetitive, and for most of the 46 chromosome ends these too are
incomplete. We do not know precisely how much sequence remains before we reach
the telomeres of each chromosome, but as with the centromeres, current
technology does not make it easy to get there. Third, there are several loci in
each individual's genome that contain members of multigene families that are
difficult to disentangle with shotgun sequencing methodologies - these multigene
families often encode proteins important for immune functions. It is likely that
the centromeres and telomeres will remain unsequenced until new technology is
developed that facilitates their sequencing. Other than these regions, there
remain a few dozen gaps scattered around the genome, some of them rather large,
but there is hope that all these will be closed in the next couple of years. In
summary: our best estimates of total genome size indicate that we have completed
about 92% of the genome. Most of the remaining DNA is highly repetitive and
unlikely to contain genes, but we cannot truly know until we sequence all of it.
Understanding the functions of all the genes and their regulation is far from
complete. The roles of junk DNA, the evolution of the genome, the differences
between individuals, and many other questions are still the subject of intense
study by laboratories all over the world.
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