Department of Mathematics, Simon Fraser University, Burnaby (BC) V5A1S6, Canada, International Graduate Training Center in Mathematical Biology, Pacific Institute for the Mathematical Sciences, Vancouver (BC), Canada, INRIA Grenoble Rhône-Alpes, Montbonnot 38334, France, Université de Lyon 1, Laboratoire de Biométrie et Biologie Évolutive, CNRS UMR5558 F-69622 Villeurbanne, France and LaBRI, Université Bordeaux I, 33405 Talence, France.|Department of Mathematics, Simon Fraser University, Burnaby (BC) V5A1S6, Canada, International Graduate Training Center in Mathematical Biology, Pacific Institute for the Mathematical Sciences, Vancouver (BC), Canada, INRIA Grenoble Rhône-Alpes, Montbonnot 38334, France, Université de Lyon 1, Laboratoire de Biométrie et Biologie Évolutive, CNRS UMR5558 F-69622 Villeurbanne, France and LaBRI, Université Bordeaux I, 33405 Talence, France.|Department of Mathematics, Simon Fraser University, Burnaby (BC) V5A1S6, Canada, International Graduate Training Center in Mathematical Biology, Pacific Institute for the Mathematical Sciences, Vancouver (BC), Canada, INRIA Grenoble Rhône-Alpes, Montbonnot 38334, France, Université de Lyon 1, Laboratoire de Biométrie et Biologie Évolutive, CNRS UMR5558 F-69622 Villeurbanne, France and LaBRI, Université Bordeaux I, 33405 Talence, France.