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20 Cards in this Set
- Front
- Back
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Phenotypic Variation that don't follow Mendels rules |
No definite or dominant or recessive allele More than 2 alleles Multiple genes involved Gene- environment interaction |
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Complete Dominance (single gene) |
Resembles one parent Phenotypic 1:2:1 |
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Incomplete Dominance (single gene) |
Doesn't resemble any parent Ex. Pure breeding white and pure breeding red results in pink 1 Red (A1A1) 1 White (A2A2) 2 Pink (A1A2) |
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Codominace (single gene) |
Resembles both parents •Heterozygotes |
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Pleiotropy (single gene) |
One gene can contribute to many phenotypic characteristics Ex. Sickle cell •Recessive lethal alleles- heart failure •Delayed lethality |
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Histocompatibility antigens |
•Cell surface molecules •Functions in Immune response to foreign antigens |
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Alle frequency |
Percentage for total number of gene copies for one allele in a population |
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Most common Allele |
Wild type (+) |
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Rare Allele |
Mutant Allele |
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Monomorphic |
Gene with only one common wild type alle |
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Polymorphic |
Gene with more than one common wild type allele •common variants- high frequency Polymorphic genes |
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Recessive lethal alleles |
2:1 ratio |
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Independent assortment |
F2 9:3:3:1 Phenotypic ratio *Only for complete dominance at both genes 3:1 |
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Epistasis |
Recessive- homozygous recessive 9:3:4 Dominant-copy of allele must mask the other gene |
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Heterogeneous traits |
•Same phenotype •Caused by mutations in different genes |
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Complementary testing |
Used to determine if a particular phenotype arises from mutations in the same or separate genes -recessive phenotypes only |
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Phenotypic Variation |
•Effects of modifier genes •Effects of environment •Pure chance |
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Penetrace |
Percentage of individuals with a particular genotype that show the expected phenotype •100 complete or incomplete |
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Expessivity |
Degree or intensity with which a particular genotype is expressed in a phenotype •Variable or unvarying |
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Modifier genes |
Alter phenotypes produced by alleles of other genes |
