BIOC51H3 Lecture : Readings 10 notes
11 Aug 2010
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Readings 10
Pg319-324
-quantitative genetics is the branch of evolutionary biology that provides tools for analyzing
the evolution of multilocus traits
-qualitative traits involve discrete traits that individuals are assigned to just by looking at
them
-most traits in organisms show continuous variation in height, athletic ability and intelligence
-quantitative traits are characters with continuously distributed phenotypes
-quantitative traits are determined by the combined influence of the genotype of many
different loci and the environment
-the alleles necessary to produce the same parental phenotypes are not lost forever but still
present in heterozygotes
-quantitative traits are determined by the combined influence of the genotype at many
different loci and the environment
Pg333-338 (refer to equations on pg 334 and 335)
-quantitative genetics includes tools for measuring heritable variation, differences in
survival/reproductive success, and predicting the evolutionary response to selection
-continuously variable traits are typically normally distributed
-within a single individual, we cannot determine the influence of nature and nurture
-we can determine the influence of nature and nurture through comparison of individuals
-heritability is the fraction of the total variation in a trait that is due to variation in genes
-phenotypic variation is the total variation in a trait, VP
-genetic variation is the variation among individuals due to variation in their genes, VG
-environmental variation is the variation among individuals due to variation in their
environments, VE
-the fraction is known as broad-sense heritability
-most traits in most populations fall somewhere in the middle, with offspring showing a
moderate resemblance to their parents
-h2 is known as the narrow-sense heritability, which is the fraction of the variation among the
parents that is due to variation in their genes
-the two components of genetic variation are additive variation and dominance variation
-additive variation is the variation among individuals due to the additive effects of genes
-dominance variation is variation among individuals that is due to gene interactions such as
dominance
-genetic variation is the sum of additive and dominance genetic variation
-narrow sense heritability allows the prediction of response to selection
-when estimating the heritability of a trait in a population, it is important to keep in mind that
offspring can resemble their parents for reasons other than the genes the offspring inherit
-twin studies are done for estimating heritability
-monozygotic twins share their environment and all of their genes, whereas dizygotic twins
share their environment and half their genes
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Document Summary
Quantitative genetics is the branch of evolutionary biology that provides tools for analyzing the evolution of multilocus traits. Qualitative traits involve discrete traits that individuals are assigned to just by looking at them. Most traits in organisms show continuous variation in height, athletic ability and intelligence. Quantitative traits are characters with continuously distributed phenotypes. Quantitative traits are determined by the combined influence of the genotype of many different loci and the environment. The alleles necessary to produce the same parental phenotypes are not lost forever but still present in heterozygotes. Quantitative traits are determined by the combined influence of the genotype at many different loci and the environment. Pg333-338 (refer to equations on pg 334 and 335) Quantitative genetics includes tools for measuring heritable variation, differences in survival/reproductive success, and predicting the evolutionary response to selection. Within a single individual, we cannot determine the influence of nature and nurture.
