Download 14–3 Human Molecular Genetics

14–3 DNA Fingerprinting and
the Human Genome Project
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14–3 Human Molecular Genetics
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
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
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
Human DNA Analysis
DNA Fingerprint: Does the DNA fingerprint from the
crime scene match with Suspect 1, 2, or 3?
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14–3 Human Molecular Genetics
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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14–3 Human Molecular Genetics
The Human Genome Project
The Human Genome Project
All the hereditary information of
an organism makes up its
genome.
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14–3 Human Molecular Genetics
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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14–3 Human Molecular Genetics
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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14–3 Human Molecular Genetics
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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14–3 Human Molecular Genetics
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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14–3 Human Molecular Genetics
Gene Therapy
The patient is infected with the modified virus
particles, which should carry the gene into cells to
correct genetic defects.
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