Map of An Epic Genetic Evolution (image) University of British Columbia Caption Greenish warblers were thought to have evolved from a single ancestral population that gradually diverged into two new species as it expanded northwards around the Tibetan plateau (grey arrows). Cutting-edge genomic approaches now show that at least two ancestral populations generated the current ring distribution (black arrows). The two populations met in northern India, where they extensively interbreed (bi-directional black arrows), and in central Siberia, where interbreeding is rare. Circles indicate 'dead ends' for gene flow. Credit Miguel Alcaide, University of British Columbia. Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.