Fig. 5

Two speciation models concerning whole genome differentiation The process of speciation initiates from genetic differentiation between population a and population b, and finishes when these two populations are evolved to species a and species b with completely differentiated genomes. a According to the genome hitchhiking and the genome-wide congealing models [8, 48], divergent positive selection targeting many loci causes whole genome differentiation with a low extent by the combined effect of mild positive selection. Following divergent positive selection rapidly accelerates the rate of whole genome differentiation by the synergistic effect of linkage disequilibrium across the whole genome until whole genome sequences are completely differentiated. In this model, whole genome differentiation is generated at the early stage of a speciation process. b According to the genic view of speciation [1], the fully differentiated loci are progressively enlarged or additional fully differentiate loci are generated until whole genome sequences are differentiated. In this model, whole genome differentiation is generated at the end of a speciation process