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ISLAMIC MEDICAL EDUCATION RESOURCES-03

0305-THE HUMAN GENOME PROJECT

Paper Presented at the Kuala Lumpur International Book Fair held at the Putra World Trade Center on 31st May 2003 by Professor Omar Hasan Kasule, Sr. omarkasule@yahoo.com

1.0  INTRODUCTION TO DNA

The cell is the basic building block of the human body. The body is made up of billions of cells. The cell has life and carries out all the functions of the body: nutrition, metabolism, excretion, and reproduction. DNA, a chemical substance in the center of the cell, controls all cellular activities by directing the production of proteins that in turn build body structures and control body activities. All cells of one person have the same type of DNA although they differ in location, size, and functions in the body.

 

DNA consists of 2 strands or chains loosely linked together. The DNA in one cell if stretched out could be more than a meter in length. The structure of DNA is surprisingly simple given its being the center of control in the cell. It consists of only 4 types of chemical substances called nucleotides designated as A, G, C, and T. One DNA molecule has nearly 3.1 nucleotides. They are arranged along the strand in various sequences that appear random but scientists have discovered that there is order in this arrangement. Each sequence of 3 nucleotides controls the production of one amino acid. The total possible number of amino acids that DNA can direct to be produce is 43 = 64. We however know that there are only about 20 amino acids. This means that some of the nucleotide triplets do not direct production of any amino acid and have other functions some of which are known and some of which are not yet known. Several amino acids combine to make proteins or enzymes. A gene is defined as the length of DNA containing nucleotide sequences that direct the production of one specific protein. Many human diseases are associated with defects in the genes.

 

2.0  THE HUMAN GENOME PROJECT

The Human Genome Project (HGP) started officially in 1990 with a projected completion time of 15 years. It was a mainly US-funded funded effort involving researchers from more than 20 institutions. Its main objective was to sequence human DNA (determine the order of all nucleotides). In addition to studying human DNA the project also studied other species such as bacteria, yeast, nematode worms, fruit fly, and the mouse. The publicly funded project was planned to go through 2 stages before reaching DNA sequencing. However one of the researchers broke away and formed a private company that went directly to the DNA sequencing and relied a lot on computer technology. In February 2001 both the public and private teams announced completion of sequencing over 90% of the human genome.

 

3.0 FINDINGS OF HGP

HGP led to several interesting results. It found that there were about 3.1 nucleotides in the human DNA[1]. Human nucleotide sequences resembled many other organisms. There are about 30,000 genes which appeared too few to control the complex human organism[2]. The DNA of all human populations of all ethnic groups and geographical areas were found to be 99.99% identical with most sequences being shared between people of different continents[3]. The number of 30,000 genes in the human is not altogether out of proportion to that found in smaller animals as shown in the table below:


Table showing Genome size and number of genes in various organisms

ORGANISM

GENOME SIZE

No. of  GENES

GENES per Million

 Nucleotides

H Influenzae (Bacterium)

1.8 MB

1,700

930

S cerevisiae (Yeast)

12 MB

6,000

500

C.Elegans (Nematode)

97MB

19,000

200

A thaliana (Plant)

100MB

25,000

200

D melanogaster (Fruit Fly)

180MB

13,000

100

H. sapiens (Human)

3,200MB

30,000– 40,000

10

Modified from: Campbell NA and Reece JB: Biology 6th edition Addison Wesley New York 2002 page 390.

 

The relatively small number of human genes is due to many segments of DNA that do not direct the production of any proteins.

 

4.0 PRACTICAL BENEFITS OF HGP

The sequencing of the human genome and identification of its genes is leading to a new revolution in medicine. It will soon be possible to identify defects in genes associated with specific diseases to help early diagnosis, treatment and prevention. The findings of HGP will also facilitate human gene therapy which is manipulation of genes to cure genetically determined disease. HGP will enable production of pharmacologic products that are tailor-made to suit the genetic structure of each individual. DNA technology will also be used for forensic purposes to assist law enforcement. Like the space program, HGP has pioneered new technologies that are finding applications in various biotechnology applications.

 

5.0 MORAL AND ETHICAL ISSUES OF HGP

The results of HGP have important findings. The uniformity of human DNA is the strongest scientific proof that humans were created from one person and corroborates the teaching of the Qur’an that we are all children of Adam. Lack of heterogeneity among DNA sequences of various ethnic and racial groups affirms the universal brotherhood of all humanity and that what appears different among humans are not biologically speaking deep. The negative side to he HGP is that people with genes known to be associated with certain disease conditions may be discriminated in employment and society. The findings of HGP open a door to incontrollable manipulation of the human genome whose outcome cannot be predicted. Loss of privacy and confidentiality is another danger because outsiders can get information about the health of a person by DNA analysis.  Commercial opportunities will raise issues about ownership of genetic information.



[1] (Sridhar GR Impact of human genome project on medical practice J Assoc Physicians of India 2001 49:959-961)

[2]  (Francke U: The human genome project: implications for the endocrinologist. Journal of Pediatric Endocrinology and Metabolism 14 Suppl 6:1395-408, 2001)

[3] (Francke U: The human genome project: implications for the endocrinologist. Journal of Pediatric Endocrinology and Metabolism 14 Suppl 6:1395-408, 2001)

Professor Omar Hasan Kasule Sr May 2003