Earliest human footprints in North America, dating violins with tree rings, and the social life of DNA

Contributing Correspondent Lizzie Wade joins host Sarah Crespi to discuss fossilized footprints left on a lake shore in North America sometime before the end of Last Glacial Maximum—possibly the earliest evidence for humans on the continent. Read the research. Next, Paolo Cherubini, a senior scientist in the dendrosciences research group at the Swiss Federal Institute for Forest, Snow and Landscape Research, discusses using tree rings to date and authenticate 17th and 18th century violins worth millions of dollars. Finally, in this month’s installment of the series of book interviews on race and science, guest host Angela Saini interviews Alondra Nelson, professor in the School of Social Science at the Institute for Advanced Study, about her 2016 book The Social Life of DNA: Race, Reparations, and Reconciliation After the Genome. Note on the closing music: Violinist Nicholas Kitchen plays Johann Sebastian Bach’s Chaconne on the violin “Castelbarco” made by Antonio Stradivari in Cremona, Italy, in 1697. Courtesy of the U.S. Library of Congress.  This week’s episode was produced with help from Podigy.