Heritability

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Heritability!

• A measure of the degree to which phenotypic
  variation in a population is attributable to
  genetic variation among individuals

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Types of Heritability

• Broad-sense reflects all possible genetic
  contributions to a populations phenotypic
  variance.
• Variation in alleles
• Dominance variation
• Epistatic effects
• Maternal effects
• Narrow-sense only takes into account the portion
  of phenotypic variance that is due to additive
  (allelic) variance.

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How to Estimate Heritability

• Twin Studies
• Identical twins (MZ) have identical genotypes, so
  any differences between (especially those raised
  apart) should be due solely to the environment
• Parent-Offspring Regression
• Slope of the line approximates heritability of
  the trait when offspring values are regressed
  against the average trait in the parents
• Statistical Models
• Analysis of variance, ANOVA
• Has to do with comparing means by splitting the
  overall observed variance into different parts

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