Priya Moorjani, Associate Professor of Molecular and Cell Biology, and her team have developed a new computational method that helps identify DNA inheritance from unknown ancient human populations using present-day human genomes. Called TRACE (TRacking Archaic Contributions via ARG Estimation), the method was used in a study that discovered genetic contributions from two extinct "ghost" lineages in our own genomes, meaning our ancestors interbred with two much older and unknown group of hominins over the course of our evolution.
This finding shows us human evolution is better understood as a story of interconnected history with continuous migration and interbreeding rather than the branching out of a family tree. Moorjani and her team also discovered that archaic ancestry is distributed all through the modern human genome, especially in regions associated with immunity and metabolic function. She's hopeful that these new computational methods will allow for a step forward in the field as new chapters of geneological relationships are uncovered without the need for ancient DNA.