BIOC51H3 Lecture 15: BGYB51H3 Lecture 15 Notes Oct 29
11 Aug 2010
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BGYB51H3 Lecture 15 Notes
-population genetics focuses on qualitative traits in which phenotypes fall into discrete
categories
-population genetics assumes that these discrete phenotypes are determined by genotypes and
not affected by the environment
-internal and external environment is important for the development of most traits
-other proteins can affect the expression of the phenotype
-biotic and abiotic factors affect phenotype
-phenotypes of individuals vary even when genotypes are the same
-rearing clones of plants with known genotypes in different environments produces different
phenotypes
-quantitative traits are characteristics for which phenotypes show continuous variation
-quantitative traits are determined by the environment and many genes
-quantitative traits focus on phenotypes and heritability as well as statistical properties of
population traits
-typical distribution of quantitative traits is normal distribution
-quantitative genetics involves measuring heritability, different lifetime reproductive success
and predicts effect of selection on phenotypes
-population level measures the fraction of the variation in a trait that is due to variation in
genes
-the greater the relative effect of genes on a trait, the stronger the evolutionary response
-the greater the relative effect of the environment on a trait, the weaker the evolutionary
response
-strong environment effect produces no evolutionary change
-variation in genes is affected by additive genetic variation and dominance genetic variation
-dominance genetic variation involves differences in dominance effects of genes
-additive genetic variation involves differences in the additive effects of genes
-heritability depends on additive genetic variation
-additive genetic variation can predict how offspring will turn out in terms of reproduction and
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-narrow sense heritability (h2) is an equation to predict the response of selection and the
fraction of total variation in a trait that is due to additive genetic variation
-to measure heritability, must control environmental effects
-in parent t offspring regression, similarities may be due to similar environments and genes
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Document Summary
Population genetics focuses on qualitative traits in which phenotypes fall into discrete categories. Population genetics assumes that these discrete phenotypes are determined by genotypes and not affected by the environment. Internal and external environment is important for the development of most traits. Other proteins can affect the expression of the phenotype. Phenotypes of individuals vary even when genotypes are the same. Rearing clones of plants with known genotypes in different environments produces different phenotypes. Quantitative traits are characteristics for which phenotypes show continuous variation. Quantitative traits are determined by the environment and many genes. Quantitative traits focus on phenotypes and heritability as well as statistical properties of population traits. Typical distribution of quantitative traits is normal distribution. Quantitative genetics involves measuring heritability, different lifetime reproductive success and predicts effect of selection on phenotypes. Population level measures the fraction of the variation in a trait that is due to variation in genes.
