140 likes | 328 Views
Quantitative Genetics. *Kolreuter – continuous phenotypic variation in tobacco plants. *discontinuous variation. *continuous variation. *Multiple-factor hypothesis. Intermediate. More variation. Variation, but similar to F 2. Additive Alleles. Quantitative Genetics.
E N D
Quantitative Genetics *Kolreuter – continuous phenotypic variation in tobacco plants *discontinuous variation *continuous variation *Multiple-factor hypothesis
Intermediate More variation Variation, but similar to F2 Additive Alleles
Normal frequency distribution: Polygenic Inheritance *Statistical Analysis Variance: *Mean *Variance *Standard Deviation *Standard Error
Polygenic Inheritance Glazier, A. et al. 2002. Finding Genes That Underlie Complex Traits. Science, 298, p.2345-2349 *Complex traits *multifactorial
Nature vs. Nurture: The Genetics View *Phenotype depends on environment and genes
Nature vs. Nurture: The Genetics View • The expression of some genes is influenced by environmental factors, such as temperature • Some alleles are heat-sensitive *Arctic foxes make fur pigment only when the weather is warm
H2 = VG VP But, P = G + E h2 = VG VP + VE Nature vs. Nurture: The Genetics View *Genetic control *Heritability Estimates of Heritability for Traits in Different Organisms
Nature vs. Nurture: The Genetics View Comparison of Concordance of Various Traits Between Monozygotic (MZ) and Dizygotic (DZ) Twins