School of Mathematical Sciences and Fujian Provincial Key Laboratory of Mathematical Modeling and High-Performance Scientific Computation, Xiamen University, Xiamen, Peoples Republic of China.|School of Mathematical Sciences and Fujian Provincial Key Laboratory of Mathematical Modeling and High-Performance Scientific Computation, Xiamen University, Xiamen, Peoples Republic of China.|Division of Hematology and Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota, United States of America.|Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, Plön, Germany.