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14–3 DNA Fingerprinting and the Human Genome Project
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14–3 Human Molecular Genetics
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Human DNA Analysis
DNA Fingerprinting
• DNA fingerprinting compares images of DNA to determine relationships among individuals.
• No two people’s fingerprints are the same.
• Twins have primarily the same DNA.
• DNA samples can be obtained from blood, sperm, and hair strands with tissue at the base.
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14–3 Human Molecular Genetics
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Human DNA Analysis
DNA fingerprints are developed with Gel Electrophoresis.
Gel Electrophoresis is a method of separating DNA fragments by passing an electric current through a gel.
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14–3 Human Molecular Genetics
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Human DNA Analysis
Step 1: Restriction enzymes are used to cut the DNA into smaller pieces.
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What is a restriction enzyme?
A protein that recognizes a specific, short nucleotide sequence and cuts the DNA only at that specific site.
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Step 2: DNA pieces are then placed in a gel between positive and negative electrodes.
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• Objects with the same electrical charge repel each other.
• DNA has a negative charge, so the DNA pieces move away from the negative electrode toward the positive electrode.
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• Gel electrophoresis sorts the DNA pieces according to size.
• Different size pieces move through the gel at different rates.
• Smaller pieces move quick and farther through the gel versus larger pieces.
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• As DNA pieces are sorted by size, they appear as lines of different lengths on the gel.
• The resulting lines are called DNA fingerprints!
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14–3 Human Molecular Genetics
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Human DNA Analysis
DNA Fingerprint: Does the DNA fingerprint from the crime scene match with Suspect 1, 2, or 3?
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DNA Fingerprints are used:
•In forensic science to solve crimes.
•To determine a child’s mother or father.
•Identify related species
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The Human Genome Project
The Human Genome Project
All the hereditary information of an organism makes up its genome.
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The Human Genome Project
In 1990, scientists began the Human Genome Project.
One goal was to identify and map the locations of all the genes in human DNA.
Second goal was to determine the sequence of the 3 billion base pairs that make up human DNA.
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The Human Genome Project
• Scientists use their data from the project to determine whether people carry the genes for certain diseases.
• Scientists then develop treatments
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The Human Genome Project
The results of the Human Genome Project have led to the possibility of using gene therapy to treat genetic disorders.
Gene therapy involves replacing a defective or missing gene in a person’s genome.
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There are several problems of using gene therapy.
1.The need to find the exact gene that cause a specific disease can be difficult.
2.It could harm people since viruses are used to transport the new genes.
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Gene Therapy
The patient is infected with the modified virus particles, which should carry the gene into cells to correct genetic defects.