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9.7 Option – Genetics: The Code Broken? : 4. The Human Genome Project
| Syllabus reference (October 2002 version) | ||
|---|---|---|
4. The Human Genome Project is
attempting to identify the position of genes on
chromosomes through whole genome sequencing |
Students learn to: |
Students: |
Extract from Biology Stage 6 Syllabus (Amended October
2002). © Board of Studies, NSW.
[Edit:16June09]
discuss the benefits of the Human Genome Project
- Completed in 2003, the Human Genome Project (HGP) was a
collaborative project that lasted for 13 years. The goals of
the project were to:
- identify all of the approximately 25,000-30,000 genes in human DNA
- determine the sequences of the 3 billion chemical base pairs that make up human DNA
- store this information in databases
- improve and develop tools for data analysis
- address the ethical, legal and social issues that may arise from the project.
- Analysis of the data will continue for many years. By licensing technologies to private companies and awarding grants for innovative research, the project accelerated the biotechnology industry and aided the development of new medical applications.
Current and potential applications and benefits of the HGP include:
Improvements in Molecular Medicine:
- improved diagnosis of inheritable diseases;
- earlier detection of genetic predispositions to disease;
- rational drug design; gene therapy and control systems for drugs.
More accurate risk assessment:
- assess health damage and risks caused by exposure to both high and low doses of radiation;
- assess health damage and risks caused by exposure to mutagenic chemicals and cancer-causing toxins;
- reduce the likelihood of heritable mutations.
Better understanding of evolution and human migration (Bioarchaeology, Anthropology, Evolution and Human Migration) :
- study evolution through germline mutations in lineages;
- study migration of different population groups based on female genetic inheritance;
- study mutations on the Y chromosome to trace lineage and migration of males;
- compare breakpoints in the evolution of mutations with ages of populations and historical events.
DNA Forensics:
- identify potential suspects whose DNA may match evidence left at crime scenes through DNA fingerprinting of samples such as blood or skin
- exonerate persons wrongly accused of crimes
- identify crime and catastrophe victims
- establish paternity and other family relationships
- match organ donors with recipients in transplant programs.
For
more information on the HGP 
US Department of Energy, Office
of Science, USA. Click on any link that you are interested in.
describe and explain the limitations of data obtained from the Human Genome Project
- It is now believed that only approximately 3% of the DNA in human chromosomes codes for proteins. The other 97% of the DNA consists of non-coding regions (sometimes called ‘junk DNA’), whose functions may include providing chromosomal structural integrity and regulating where, when, and in what quantity proteins are made. The use of about 50% of this ‘"junk DNA" is not known.
- Some genes are found inside other genes, thus making their identification difficult.
- Non-coding DNA is used in DNA fingerprinting.
- It may be a long time before scientists totally understand the role of every gene, its interaction with other genes and how DNA relates to such things as behaviour, brain function and other aspects of neurobiology.
- Some other limitations of the Human Genome Project
involve ethical, legal and social implications such as:
- fairness in the use of genetic information
- privacy and confidentiality
- psychological impact and stigmatisation
- education, standards and quality control
- commercialisation
- conceptual and philosophical implications.
process information from secondary sources to assess the reasons why the Human Genome Project could not be achieved by studying linkage maps
- Use the information below, your teacher and any other information fellow students have obtained from the internet, text books and magazines and journals.
- Process the information by putting it into an ordered form and comparing the information from the various sources.
- Extract from the information the reasons why the HGP could not be achieved by studying linkage maps.
Useful information
Linkage maps consist of genes that have been mapped and which have been isolated according to the DNA from living humans. Only hereditary diseases contribute to the linkage maps.
The human genome consists of thousands of genes that are responsible for every characteristic and function of the body and so many do not code for hereditary diseases. Linkage maps would have only provided information about hereditary diseases for the Human Genome Project and not for all the other many genes.
outline the procedure to produce recombinant DNA
- Human insulin is made using recombinant DNA. The
Eschericia coli bacteria are used to do this in the
following way:
- The human gene for making insulin is cut out of the chromosome taken from a human pancreas cell (Islets of Langerhans cell) using an enzyme called restriction enzyme.
- A ring of DNA called a plasmid is removed from the E.coli bacterium and cut open with a restriction enzyme.
- The human insulin gene is mixed with the cut plasmid. All of the cut ends (“"sticky ends"”) can bond together using the enzyme DNA ligase to make a new DNA molecule.
- The “"new"” plasmid, that contains the recombinant DNA, is inserted back into the bacterial cell.
- When the bacterial cell reproduces, so does the plasmid and hence the human insulin gene. When provided with the appropriate nutrients, these cells produce human insulin which can be extracted and used by diabetics.
- Recombinant DNA can also be used in:
- the production of human growth hormone
- a protein that dissolves blood clots and so can be used to treat heart conditions
- bacteria to break down toxic waste in oil spills
- pest resistance in some plants, such as giving cotton resistance to the cotton boll weevil.
explain how the use of recombinant DNA technology can identify the position of a gene on a chromosome
- A specific sequence of DNA that is complementary to the other DNA bases on a gene or part of a gene is called a probe. Probes can be prepared, cloned and labelled with a special fluorescent dye. These probes can bond to single complementary strands of DNA from samples. These labels will fluoresce or glow when placed under a fluorescent light and so the position of that gene can be observed and recorded. This can be used to determine which chromosome and the specific position on the chromosome, of that gene. Genetic screening to identify abnormal chromosomes and defective genes, uses this technique.
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