Dr. Sherwood Githens will discuss David Reich’s 2018 book, Who We Are And How We Got Here: Ancient DNA And The New Science Of The Human Past. “Ancient DNA” refers to DNA extracted from human bones 50,000 years old and more -- including Neanderthals -- which is then sequenced. These ancient DNA sequences have allowed scientists to determine some of the relationships among migrations of groups of humans that are not possible using modern DNA sequences. The migrations of humans during prehistory in Africa, Europe, Asia, the South Seas, and the Americas will be summarized. Sherwood holds a Ph.D in biochemistry from Harvard University and has held numerous university teaching and administrative positions throughout his career.