12.3 Other Inheritance Patterns

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What is codominance?

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A genetic scenario where both alleles in a heterozygote are fully expressed, resulting in offspring with a phenotype that is neither dominant nor recessive. Example: AB blood type, where both A and B antigens are present.

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What is incomplete dominance?

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A genetic situation where the phenotype of a heterozygote is intermediate between the phenotypes of the two homozygotes. Example: A red flower crossed with a white flower produces pink flowers.

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What is polygenic inheritance?

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A type of inheritance where multiple genes influence a single trait, resulting in a wide range of phenotypes. Example: Human height, which is affected by several genes.

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What are multiple alleles?

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A situation where more than two alleles exist for a genetic trait. Example: Blood type in humans, which has three alleles: I^A, I^B, and i.

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What is complete dominance?

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A genetic relationship where one allele completely masks the effect of another allele in a heterozygote. Example: In pea plants, the allele for tall plants (T) is completely dominant over the allele for short plants (t).

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What is an example of codominance in plants?

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An example of codominance in plants is when a red-flowered plant is crossed with a white-flowered plant, resulting in a plant with both red and white flowers.

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What is an example of polygenic inheritance in humans?

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An example of polygenic inheritance in humans is skin color, which is determined by multiple genes.

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What is the genotype for type B blood?

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Possible genotypes for type B blood include I^BI^B and I^Bi.

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What is the genotype for type A blood?

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Possible genotypes for type A blood include I^AI^A and I^Ai.

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What is the genotype for type O blood?

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The genotype for type O blood is ii.