Explore population genetics in large genealogies through this informative lecture by Simon Gravel at the Computational Genomics Summer Institute. Delve into the fascinating world of data scavenging, learning relationships, and identifying closed relatives using examples from Iceland and French Canadian history. Discover how genealogical data can be used to reconstruct relatives and make inferences about population dynamics. Examine the extent of genealogical records in Quebec and understand the importance of simulation data in population genetics research. Gain insights into the selective advantages of expanding populations and the transmission of rare alleles through large-scale genealogies.