Incomplete Dominance and Codominance

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Incomplete Dominance and Codominance
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Review

• In pea plants, yellow flowers is recessive and
  purple flowers is dominant. What is the phenotype
  of a individual with the genotype Pp?

THE DOMINANT GENE ALWAYS RULES
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Incomplete Dominance

• In incomplete dominance, there is no recessive
  allele. Instead, in a heterozygous individual an
  intermediate phenotype is produced.
• For example in flower colors with incomplete
  dominance, a red allele (R) with a white allele
  (W) would produce a pink flower

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Example Problem

• When a mouse with black fur (B) is crossed with a
  mouse with white fur (W), what is the phenotypic
  ratio for the F1 generation

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Example Problem 2

• What is the expected phenotypic ratio of the F1
  generation when a gray mouse is crossed with a
  white mouse?

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Codominance

• Codominance a relationship among alleles where
  both alleles contribute to the phenotype of the
  heterozygote. However, instead of getting a blend
  you see both colors.
• For example in flower colors with Codominance, a
  red allele (R) with a white allele (W) would
  produce a red and white spotted flower

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Example Problem

• When a cattle with red fur (R) is crossed with a
  cattle with white fur (W), what is the phenotypic
  ratio for the F1 generation. This gene follows
  the codominance pattern of inheritance

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Example Problem 2

• What is the expected phenotypic ratio of the F1
  generation when a roan cattle (red and white
  spots) is crossed with a red cattle?

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Identify as codominance or incomplete dominance.
Then write how the other type of inheritance
would be represented

• a) Birds can be blue, white, or white with
  blue-tipped feathers.
• b) Flowers can be white, pink, or red.
• c) A Sneech can be tall, medium, or short.
• d) A Bleexo can be spotted, black, or white.
• e) A mouse can be black, white, or gray

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Blood Type Genetics
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Parts of the Blood

• Red Blood Cells carry oxygen to body tissues
• Plasma - the liquid part of blood. It contains
  many important substances which must be carried
  around the body. For example it transports Carbon
  dioxide hormones, vitamins, antibodies
• Platelets help in the clotting process
• White blood cells fight infections

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What Blood Types are?

• The differences in human blood are due to the
  presence or absence of certain protein molecules
  called antigens and antibodies.
• The antigens are located on the surface of the
  red blood cells and the antibodies are in the
  blood plasma.
• Individuals have different types and combinations
  of these molecules. The blood group you belong to
  depends on what you have inherited from your
  parents.

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WHAT????

• Antibodies fight foreign antigens in the body.

ANTIGEN B
ANTI B ANTIBODY
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• 4 Blood Types
• Type A
• Type A antigens on blood cells
• Type B
• Type B antigens on red blood cells
• Type AB (universal recipient)
• Both A and B antigens on red blood cells
• Type O (universal donor)
• Neither A nor B antigens on red blood cell

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Blood Type Chart
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Adding the wrong blood type
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Blood Transfusion

• A blood transfusion process of transferring
  blood from one person into the circulatory system
  of another.
• Based on the blood chart table, what type of
  blood can be used in a transfusion of a person
  with B type blood?

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Blood Transfusion

• Based on the blood chart table, what type of
  blood can be used in a transfusion of a person
  with A type blood?
• Based on the blood chart table, what type of
  blood can be used in a transfusion of a person
  with AB type blood?

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Blood Transfusion

• Based on the blood chart table, what type of
  blood can be used in a transfusion of a person
  with O type blood?

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Blood type inheritance

• Human blood type is determined by codominant
  alleles.
• There are three different alleles, known as IA,
  IB, and i. The IA and IB alleles are codominant,
  and the i allele is recessive.

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Blood type inheritance
Blood Type Possible Genotypes
A IAIA IAi
B IBIB IBi
AB IAIB
O ii
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Practice Questions

• Could a father with A type blood and a mother
  with AB type blood produce a son with O type
  blood?

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Practice Questions

• Could a father with O type blood and a mother
  with AB type blood produce a son with O type
  blood?

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Practice Questions

• Could a father with A type blood and a mother
  with B type blood produce a son with B type
  blood?

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Practice Questions

• What is the probability that an AB blood type
  father and an IAi mother will produce a child
  with a B blood type?