GENETICS
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Transcript of GENETICS
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GENETICSGene Control, Cancer and
Genetic Techniques
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All cells have the same DNA, but not all cells produce the same proteins; how does this happen?
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GENE CONTROL Gene expression controlled by:
Using promoters—sections of DNA that bind RNA polymerase to make mRNA
Using repressors—proteins that bind DNA to turn off genes
Permanently turning off genesControl RNA splicing
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CANCER Uncontrolled, abnormal cell division Cancer can be caused by genetic
factors, environmental factors, or a combination of both
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ONCOGENE A gene that causes a cell to become
cancerous A gene can become an oncogene in 3 ways:
Mutation occurs in a growth-factor gene (a gene that controls cell division)
Error in DNA replication results in multiple copies of a single growth-factor gene
A change in a gene’s location
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TUMOR SUPPRESSOR GENE Gene responsible for preventing
uncontrolled cell growth If a gene mutation occurs in a tumor
suppressor gene so that it does not work anymore, uncontrolled cell growth could result
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CARCINOGEN & MUTAGEN Carcinogen: an agent that causes or
tends to cause cancer (ex: UV radiation or tars in cigarette smoke)
Mutagen: a factor in the environment that can cause mutations in DNA (ex: radiation)
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REDUCING CANCER RISK Screening tests such as mammograms,
Pap smears and prostate screenings should be done
Healthy behaviors:Avoid smokingEat a low fat dietEat a high fiber dietUse sunscreen
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DNA FINGERPRINTING Procedure that creates a DNA profile Because no two people on this earth can
have the same DNA (with the exception of identical twins), each profile is unique to each person, like a fingerprint
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USES FOR A DNA PROFILETissue Matching: used to match crime scene evidence to a suspect or to help identify a bodyInheritance Matching: used to determine paternity
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TISSUE MATCHING EXAMPLE
The two samples must have the same band pattern
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INHERITANCE MATCHING EXAMPLE
Each band in a child’s DNA fingerprint must be present in at least one parent
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CREATING A DNA FINGERPRINT1. Extraction: DNA must be removed from
the nucleus of the cells
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CREATING A DNA FINGERPRINT (CONT.)2. Restriction Fragments: Restriction
enzymes are used to cut apart the DNA at specific sites
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CREATING A DNA FINGERPRINT (CONT.)3. Amplification: Polymerase
Chain Reaction (PCR) generates multiple identical copies from trace amounts of DNA
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CREATING A DNA FINGERPRINT (CONT.)4. Electrophoresis:
In this process, DNA fragments created through PCR are separated by using an electrical fieldDNA is negatively charged and will move towards a positive electrodeThe smaller the fragment, the faster it will travel