Plot representation of the frequency of variable sites across the mitochondrial genome of C. sinicus. The sliding-window was 200 bp in length and slid 2 bp at a time. Eleven individuals from four populations were used to determine the intraspecific distribution pattern of the variable sites. The bar at the top illustrates the position and orientation of each gene. The shaded boxes on the x-axis indicate sections that were not covered during the comparison. The horizontal line indicates the mean value of the frequency.