Human
Genome project (HGP) is an international project whose principal goal was to sequence the
entire human genome. The National Centre for Human Genome Research(NCHGR) was
established in the United States in 1989 by James D. Watson, and subsequently
by Francis Collins. It was a 13 years project coordinated by the U.S.
Department of energy and the national institutes of health.
HGP researchers have deciphered the human genome in
following ways:
- To develop a high resolution genetic map of the human genome,
- To produce a variety of physical maps of all human chromosomes and
of the DNA of selected model organisms (ie, Escherichia coli,
Saccharomyces cerevisiae, nematode (Caenorhabditis elegans), Drosophila
and the laboratory mouse.
- To determine a complete sequence of human DNA and the DNA of model
organimsms.
- To Develop capabilities for collecting, storing, distributing, and
analysing the data produced
- To create the appropriate innovative and high risk techniques
necessary to achieve these objectives.
- To develop programs to address the understanding of the ethical,
legal, and social implications (ELSI) of the HGP.
Genome is the entire DNA in an organism, including
its genes. Human genome is made up of 23 chromosomes pairs with a total of 2.9
billion base pairs encoding approximately 20,000 to 25,000 genes. All human
cells except for mature red blood cells contain a complete genome.
Genes are specific sequences of bases that encode instructions
for making proteins. Genes comprises of only 2% of the human genome, the remainder
consists of non coding regions. An average gene consists of 3000 bases, but
sizes vary greatly with the largest known human gene being dystrophin at 2.4
million bases.
In 2002 some facts about the human genome project
was found as:
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The number of genes is almost one third of the expected, about as many
as lower organisms and fewer than some
Ø
Human genes are able to encode more proteins than the genes of lower organisms.
Ø
Human proteins are more complex than the protein of similar functions in
lower organisms.
Ø
Human genes are not arranged evenly; the ends of chromosomes are more
tightly packed.
Ø
About 200 human genes arrived in the mammalian genome directly from
bacteria
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Only about 2.5 % of human DNA encodes proteins. Some of the DNA that
does not encode genes probably has important functions
Ø
The mutation rate in male is twice than in female
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All human are 99.9% identical in terms of their nucleotide sequence. All
the ethnic groups share most genetic differences.
The
objective of HGP is helpful in providing scientists with a powerful tool to
help them understand the molecular essence of tragic and devastating illness
such as schizophrenia, alcoholism, Alzheimer disease, and manic depression. This
has lead to improved approaches to predict increased risk, provide early
detection, and promote more effective treatment strategies.
Single Nucleotide Polymorphisms (SNPs)
The Human Genome Project has helped to inform us
about how remarkably similar all human beings are—99.9% at the DNA level. About 99.9 % of nucleotide
bases are exactly the same in all the people. However, this 0.1 % variation of
genome within population is currently a focus of intense research, because the
data will provide information about increased susceptibility or resistances to
diseases. The most common variations are single nucleotide polymorphisms
(SNPs). When two haploid genomes are compared, SNPs occur every kilobase, on
average, other kinds of sequence variation such as copy number changes,
insertions, deletions, duplications, and rearrangements also exist, but at low
frequency and their distribution is poorly understood.
SNPs are abundant, stable, widely distributed
across the genome. SNPs offer the highest resolution for tracking disease genes
and population history. SNPs have potential for mapping complex traits such as
cancer, diabetes, and mental illness. Therefore, SNP maps are desirable for
identifying genes that make a small contribution to disease risk. In some
instances, such maps will also permit predict of individual differences in drug
response.
Proteomics:
The constellation of all proteins in a cell is
called its proteome. Unlike the relatively unchanging genome, the dynamic
proteome changes from minute to minute in response to tens of thousands of
intra and extra cellular environmental signals. A protein’s chemistry and behaviour
are specified by the gene sequence and by the number and identities of other
proteins made in the same cell at the same time. This explains how over a
million of modified proteins can exist when the entire human genome codes for
less than 30,000 genes.
Human Genome
Project in Clinical medicine
Technology and resources promoted by the Human Genome Project are
starting to have profound impacts on biomedical research and promise to
revolutionize the wider spectrum of biological research and clinical medicine.
Some current and potential applications of genome research include
- Molecular medicine
- Risk assessment
- DNA forensics
(identification)
The main aim of human genome project is its
applications in molecular medicine. Genomic information helps researches to
design drugs targeted at specific pathways involved in the disease. With
correct genomic information, doctors can deliver correct drugs and drug dosages
that are most likely to work well. These drugs are believed to work better and
cause fewer side effects than current treatments. Gene based drugs in the
treatment of leukaemia and other cancers have already started to pay off.
Understanding the human genome will have an
enormous impact on the ability to assess risks posed to individuals by exposure
to toxic agents. Scientists know that genetic differences make some people more
susceptible and others more resistant to such agents. Therefore genomic
information are valuable source of predicting disease so that more attention is
paid for preventing that disease. For instance: if the genome contains
variations that raise the risk of heart disease, people might exercise more and
take drugs that lower cholesterol.
Understanding genomics will help us understand
human evolution and the common biology we share with all of life. Comparative
genomics between humans and other organisms such as mice already has led to
similar genes associated with diseases and traits. Further comparative studies
will help determine the yet-unknown function of thousands of other genes.
Understanding
genomics provides valuable source is DNA forensics. It can be used to identify
potential suspects whose DNA may match
evidence left at crime scenes and to exonerate persons wrongly accused of
crimes.
It can
also be used in establishing paternity and other family relationships.
Another
advantage of studying human genome is to match organ donors with recipients in
transplant programs.
