May 9, 2018
Jinko Graham, Simon Fraser University
Combining Phenotypes, Genotypes and Genealogies to Find Trait-influencing Variants
A basic tenet of statistical genetics is that shared ancestry leads to trait similarities in individuals. Related individuals share segments of their genome, derived from a common ancestor. The coalescent is a popular mathematical model of the shared ancestry that represents the relationships amongst segments as a set of binary trees, or genealogies, along the genome. While these genealogies cannot be observed directly, the genetic-marker data enable us to sample from their posterior distribution. For each genealogical tree that is sampled, we may compare the clustering of trait values to the clustering obtained under the prior distribution. This comparison provides a latent pvalue that reflects the degree of surprise about the prior distribution in the sampled tree. The distribution of these latent pvalues is the fuzzy pvalue as defined by Geyer and Thompson. The fuzzy pvalue contrasts the prior and posterior distributions and is informative for mapping trait-influencing variants. In this talk, I will discuss these ideas with application to data from an immune-marker study, present results from preliminary analyses and highlight potential avenues for further research.