test III

test III - Test III Material Polygenic inheritance...

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Test III Material Polygenic inheritance Proportion of an individual’s phenotype due to its genotype (Vg) and environment (Ve) Instead, proportion of variation in phenotype due to genotype vs environment Phenotypic variation is described by the variance To determine the mean = X = Sigma Xi/n n = total number in the population ---Total variance of a trait (s^2) = V total = Sigma (X-Xi)^2 / n – 1 Vtotal = Vg + Ve Vt = 26.66 Vg = 21.33 Ve = 5.33 Broad sense heritability- proportion of total variance due to genetic factors (V_)- H2 H2 = Vg/Vt = 0.8 (can only be from 0 to 1) Scientists would like to predict offspring population Vg: Vd (dominant alleles) Va (additive alleles= partial dominance) Vep (epistatic) Vg = Vd + Va Variability due to dominance/recessive/epistasis is not very informative because of masking More interested in proportion of variation due to additive alleles Proportion of TOTAL variance due to Va- Narrow sense heritability- predicts proportions of additive alleles h2 = Va/Vt ---Can be used to predict the h2 near 0 means Va is a small part of the total variation, rest is from Vd and Ve h2 = (mean of offspring – population mean)/(mean of parents – population mean) high h2 values better material for selective breeding experiments In Humans: Concordant- both are same traits, passed on Discordant- different traits passed on Recombination Mendel- Segregation- only 1 allele at each locus Independent assortment- alleles assort independently in meiosis Morgon and students 1910-
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Genes located on chromosomes More than 1 gene located on same chromosome Lack of independent assortment suggested genes were linked
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test III - Test III Material Polygenic inheritance...

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