In the second lecture, Dr. Matthew State overviews the hunt for genes associated with autism and explains how studying de-novo rare mutations in the germline has advanced the understanding of the genetics of autism spectrum disorder (ASD). Studying a cohort of families with one affected individual and one unaffected sibling, they were able to map multiple genes involved in ASD. Because of the complexity of the developing brain, the same gene could act upon different regions of the brain at different times during development. Therefore, after identifying genes associated with ASD, they characterized the region and time during development where these genes are expressed and more likely to have an effect that is associated with ASD.