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Exception |
Definition |
Example |
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Multiple Alleles:
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A series of three or more alternative forms of genes, only two of which can exist in any normal diploid individual. |
Human Blood Type-there are different forms of blood such as A, A+, A-, B+, B-, etc. |
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Co-dominance:
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Two different alleles that are fully expressed in a heterozygous individual.
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Flowers which show more than one color- tulips that can show both red and white shades of color. |
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Incomplete Dominance:
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The appearance in a heterozygote of a trait that is intermediate between either of the trait's homozygous phenotype. |
Flowers that show a blend between colors- a flower that has both red and white alleles come together and make pink. |
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Lethal Allele Combinations:
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Alleles that cause an organism to die, where the gene involved is essential to the organism to live. |
Sickle Cell Anemia- has the affect to kill the host of this disorder. |
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Pleiotropy:
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One gene being responsible for affecting more than one phenotypic characteristic. |
PKU (phenylketonuria)- a gene disorder that plays a role in many different phenotypic characteristics. |
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Phenocopy:
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Environmentally induced, non-genetic, alteration of a phenotype that resembles a genetic mutation. |
Vanessa Genus of Butterflies, the ability to change its color depending on local temperature. |
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Heterogeneity:
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Composed of different genes that affect the same phenotype. |
Hearing loss- there is 132 forms of alleles for this disorder |
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Epistasis:
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A combination of genes which has a dominant affect over other genes. |
Albinism- they still have the gene for pigment color but have an albinism gene that masks the affect of it. |
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Penetrance:
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A percentage of a gene that is expressed in a group of organisms. |
Polydacyl- is expressed as a percent from a group of people. |
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Expressivity:
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The degree of which a particular gene produces its effect in an organisms. |
Hair Color- Many different people can express different shades of hair color such as brown, light brown, dark brown, blond, dirty blond, etc. |
