Suture zones, speciation, and evolution

In the more than 50 years since the initial conceptualization of the suture zone, little work has been done to take full advantage of the comparative capability of these geographic regions. During this time, great advances have been made in hybrid zone research that have provided invaluable insight into speciation and evolution. Hybrid zones have long been recognized to be "windows to the evolutionary process." If a single hybrid zone provides a window, then multiple hybrid zones in a suture zone can provide a panoramic view of the evolutionary process. Here, we hope to redirect attention to suture zones, bring the advances from hybrid zone research to a comparative framework, and further expand our understanding of speciation and evolution. In this review, we recount the historical discussions surrounding suture zones, briefly review what we can learn from hybrid zones, and review the comparative studies done on suture zones thus far. We also highlight the opportunities and challenges of performing research in suture zones to help guide researchers hoping to start a research project in these regions. Lastly, we propose future directions and questions for comparative research that can be done in suture zones.