On the Number of Genealogical Ancestors Tracing to Source Groups in Admixed Populations

Explore a conference talk from the Computational Genomics Summer Institute (CGSI) that delves into the number of genealogical ancestors tracing to source groups in admixed populations. Learn about a mechanistic model of admixture and its application to improve understanding of African American history. Discover how ancestry proportions from the present can estimate the number of ancestors from each source population contributing to an admixed individual's genome. Examine the relationship between African and European ancestors in African American genealogy, including how their numbers vary per generation and peak during the Trans-Atlantic Slave Trade. Gain insights into using global ancestry to infer admixture history and understand the complex signatures of sex-biased admixture on the X chromosome.

Intro
Overview
Only some of your genealogical ancestors will be your genetic ancestors
Admixed populations are a combination of multiple sources
Individual genomes carry signatures of admixture
Classically admixture has been modelled by considering simpler scenarios
Implement a mechanistic model of admixture
Use ancestry proportions from the present to estimate, Z, the number of ancestors from each source population that contributed to genome of an admixed individual
Implementing the model to improve our understanding of African American history
Summary of our approach for fitting the model
Model assumptions
Estimating the number of genealogical ancestors. that are represented in an African American individual's genome
Estimating the number of genealogical ancestors that are represented in an African American individual's genome
Hundreds of African ancestors and tens of European ancestors
As the number of African ancestors increases the number of European ancestors decreases
ancestry occurs during the initial epoch
Number of African and European ancestors varies per generation
The probability of having an African or European ancestor peaks during the height of the Trans- Atlantic Slave Trade
Global ancestry can be used to infer the admixture history of admixed individuals