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MUTATIONS

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					MUTATIONS

What is Mutation?
   Mutation is a change in a
    gene/chromosome due to an error in
    meiosis or mitosis/ due to an
    environmental factor.
   What causes DNA mutations?
   Change in a gene/chromosome
   X-ray
   Chemical
   Nuclear radiation
   Ultraviolet light
   A condition caused by mutations in one or
    more genes is called a genetic disorder.

   A genetic disorder is a disease that is
    caused by an abnormality in an
    individual’s DNA.

   Abnormalities can range from a small
    mutation in a single gene to the entire
    chromosome.
          Effects of Mutations

   Source of genetic variety
   Some mutations are harmful, some are
    helpful, and others are neither harmful nor
    helpful.
   A mutation is harmful to an organism if it
    reduces the organism’s chance for survival
    and reproduction.
          Causes of Mutations
   Albinos (having pale and colorless skin)
   Fruit flies have legs in place of antennas.
   Double mutant (snake that is both albino
    and has 2 heads)
   People who completely covered in a fur-
    like coat of hair.
   Newborn babies with extended
    tailbone/sixth fingers.
          Causes of Mutations

   Turner Syndrome
   Clover which has 4 leaves
   Down Syndrome
   Sickle Cell Disease
   Colon Cancer/breast cancer/ovarian
   Alzheimer’s disease
     Mutations in multiple genes

   often coupled with environmental causes

   Colon cancer, breast/ovarian cancer,
    Alzheimer’s disease
       Chromosome Abnormalities

   Down Syndrome (extra copy of
    chromosome 21)

   Turner Syndrome (missing one X
    chromosome)
           Single gene disorder
   Sickle cell disease
   For e.g. blood contains RBC that transport
    oxygen around our bodies. The cells use a
    protein called “hemoglobin” to capture and carry
    the oxygen.
   Of our 35,000 genes, only a few contain the
    instruction for making hemoglobin proteins.
   If our hemoglobin gene is normal, the
    hemoglobin protein works fine.

   But if the instruction in that gene are
    changed/mutated, changes in the
    hemoglobin protein could result.

   One such mutation causes a disorder
    called sickle cell anemia.
       Helpful mutations/beneficial
                mutations
   These mutations lead to new versions of
    proteins that help an organism and its
    future generations better adapt to
    changes in their environment.

   E.g. changes in butterflies color, making it
    harder for predators to see it.

				
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posted:7/28/2011
language:English
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