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12 Cards in this Set
- Front
- Back
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QUANTITATIVE GENETICS |
genetic analysis of complex characteristics |
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QUANTITATIVE CHARACTERISTICS |
also known as continuous characteristics |
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QUANTITATIVE CHARACTERISTICS |
..characteristics that vary continuously along a scale of measurements with many overlapping phenotypes ..individual's phenotype must be described with a quantitative measurement |
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POLYGENIC and ENVIRONMENTAL FACTOR |
two phenomena involved |
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POLYGENIC |
they are influenced by genes at many loci |
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POLYGENIC |
many genotypes are possible, each producing a slightly different phenotype |
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ENVIRONMENTAL FACTOR |
environmental differences result in a single genotype producing a range of phenotypes |
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MULTIFACTORIAL |
varying characteristics are both polygenic and influenced by environmental factors |
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DISCONTINUOUS CHARACTERISTICS |
..the relationship of genotype and ohenotype is straightforward ..each genotype produce a single phenotype, and most phenotypes are encoded by a single genotype ..dominance and epistasis may allow two or three genotypes to produce same phenotype, but the relationship remain simple |
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CONTINUOUS CHARACTERISTICS |
..the relationship of phenotype and genotype are often more complex
..if the characteristic is polygenic, many different genotypes are possible, several of which may produce the same phenotype
..due to environmental effects, the same genotypes may produce a range of potential phenotypes which may overlap |
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MERISTIC CHARACTERISTICS |
..not continuous but determined by multiple genetic and environmental factors ..measured in whole number ..has a limited number of distinct phenotypes |
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THRESHOLD CHARACTERISTICS |
..measured by presence of absence ..exhibit only two phenotypes but are determined by multiple genetic and environmental factors ..when susceptibility is larger than the threshold value, a specific trait is expressed |
