The domestic dog has undergone intensive human-driven selective pressure to produce canines of a particular appearance and behaviors. The result has been the development of over 350 modern breeds, most with human or geographic- induced barriers to gene flow, resulting in fixed traits that reliably track through multiple generations. Recent studies in our lab have focused on decoding the genetic basis of morphologic traits that both vary between and define dog breeds. That work demonstrated a now recurring theme in dog genetics; many highly variable phenotypes are controlled by variation in small numbers of genes, as opposed to humans, where subtle differences in phenotype tend to be controlled by large numbers of variants. As we show, this difference likely represents the recent development of most breeds within the last 300 years in Western Europe. In this study, we describe whole genome sequence analysis (WGS) of over 1000 dogs, identifying genes for morphology, aging, and a host of other traits. Since disease susceptibility is one of the ways in which dog populations are most well-poised to inform human health, we also applied our analysis of canine WGS to canine cancer, demonstrating the presence of genes that serve as drivers of tumor growth. Finally, we examine a population of dogs thought to be extinct in the wild, demonstrating the utility of genomic approaches for understanding canine history and relatedness.