Frequency line charts of inter- and intra-specific genetic distances based on 338 dataset. The x-axis represents the genetic distance, and the y-axis represents the occurrence times in the whole genetic distance matrix. Each peak was a data point with corresponding genetic distance and occurrence times. The data points on the green and red line were calculated with the interspecific distances, and the points on purple and blue line were calculated with the intraspecific distances. The overlap region, which was the crossing area of inter- and intra-specific divergence, is indicated by the red dotted rectangle. Each gene was signified in one chart: the top half was calculated with all the 338 samples; and the bottom half was scored by eliminating the queried samples of Chaetosiphella longirostris.