Blood Type

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Blood Type
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• Blood type is a good example for studying complex
  patterns of heredity, because it is an example of
  codominance, and multiple alleles for a trait.
• It is an example of multiple alleles because
  there are three possible alleles for blood type
  A, B, and O.
• It is an example of codominance because type A
  and type B are both dominant over O.

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• The A allele is a gene that codes for the A
  protein on the cell membrane of blood cells.

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• The B allele is a gene that codes for the B
  protein on the cell membrane of blood cells.

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• The O allele does not code for any protein
  markers on the blood cells.

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Possible Genotypes

• The A, B, and O alleles can combine to form 6
  possible genotypes. What are they?
• AA, AO, AB, BB, BO, and OO

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Blood Types

• From the genotypes, there are 4 possible blood
  types
• Type A (AA or AO)
• Type B (BB or BO)
• Type AB (AB)
• Type O (OO)

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Blood Transfusions

• Why cant we receive blood transfusions from
  anyone?
• Our immune system attacks cells it doesnt
  recognize this helps protect us from things
  like bacteria, but it also means the body will
  attack cells that have surface markers they dont
  recognize.
• Someone with Type A blood cant receive Type B or
  AB blood, but they can accept Type A or Type O.
  Why?

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• If a person receives a transfusion from an
  incompatible blood type, it will cause
  agglutination (clumping) of the blood as their
  immune system attacks and kills the foreign blood
  cells.

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Blood Type Compatibility
Blood type of recipient
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Determining Blood Type

• To test a persons blood type, a small sample of
  blood is taken and combined with an Anti-A serum
  and an Anti-B serum.
• Type A blood will only react (clump) with Anti-A.
• Type B will only react with Anti-B.
• Type AB will react with both.
• Type O will not react.