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15 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Quantitative genetics |
Genetic analysis of complex characteristics |
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Quantitative characteristics |
Characteristics that vary continuously along a scale of measurements with many overlapping phenotypes |
Also called continuous characteristics |
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Phenomena involved in QG |
1. Many are polygenic, meaning they are influenced by genes at many loci |
Many genotypes are possible producing slightly different phenotype |
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Phenomena involved in QG |
2. Arise when environmental factors affect phenotype |
Environmental differences result in a single genotype producing a range of phenotypes |
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Multifactorial |
Most continuous characteristicd are both polygenic and environmentally affected and are said to be |
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Discontinuous characteristics |
Straightforward relationship of phenotype and genotype |
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Discontinuous characteristics |
Each genotype produces single phenotype and most phenotypes are encoded by single genotype |
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Dominance and epistasis |
Allows two or three genotypes to produce same phenotype but relation remains simple |
Discontinuous characteristics |
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Continuous characteristics |
Complex relationship between phenotype and genotype |
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True |
If characteristic is polygenic, many different genotypes are possible which produce same phenotype |
Continuous characteristics |
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False |
Due to environmental effects different phenotype may produce range of potential phenotypes which may overlap |
Continuous characteristics: same phenotype |
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Meristic characteristic |
Not continuous but are determined by multiple genetic and environmental factors |
Measured in whole number (e.g. animal litter size) and has limited number of distinct phenotypes |
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Threshold characteristic |
Measured by presence or absence exhibiting only two phenotypes but are determind by multiple genetic and environmental factors |
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Liability or risk |
Underlying susceptibility |
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True |
When susceptibility is larger than a thershold value, a specific trait is expressed |
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