What makes a species? Driven largely by our natural inclination to categorize, we tend to think of all living things in discrete units – species – related to each other in a clearly defined taxonomic hierarchy into which every one fits neatly. New species emerge as evolutionary changes accumulate within one, leading to reproductive barriers that eventually split that one species into two. Hybrids, however, challenge this notion. As more and more genomes are sequenced, scientists are beginning to discover how common hybridization is in the wild, and that speciation may not be the directional – and irreversible – process we thought we understood. Through the remarkable and complex story of the evolution of the polar bear, I will discuss how hybridization may help to shape genomic diversity in wild populations, including aiding the survival of species during periods of dramatic environmental change. I will ask the question: is there really such a thing as a brown bear?
Shapiro, Beth, "Liger, Tigons and Bears (Oh My!): The Genomic Consequences of Inter-species Hybridization" (2013). IMSA Great Minds Program ®. 21.