Chapter 7, Population Genetics by Graham Coop

Phenotypic Variation and the Resemblance Between Relatives.

Presented by Ashvin Ravi and Ariana Chriss

The chapter starts with discussion of additive genetic variance and how it contributes to heritability. Rare variants with high effects on phenotype contribute to smaller proportion of heritability compared to common variants (higher MAF) with smaller effects on phenotype.

Narrow sense heritability: Proportion of the variance that is explained by the additive genetic effect.

The main concept is that we can estimate the additive genetic variance and the heritability by using the resemblance of relatives, if we can experimentally remove or statistically partition out the effect of the shared environment among relatives.

Note: This paper discusses how the estimated genetic variance of the quantitative traits does not measure the “underlying genetic architecture” but the assumed genetic architecture and its corresponding parametrization. When the assumption and parameterization change, the partitioning of variance components also changes.