Fig. 1

Polymorphic edge detection by k-mer method a k-mers (k = 20) from all positions of short reads are obtained. b k-mers are sorted and counted. c Sorted k-mers are divided into first (k-1)-mer and last base, and converted to (k-1)-mer following counts of last A, C, G and T. d The last-base-count data from target and control are joined by (k-1)-mer sequence. If the pattern of counts is different, the last base may be the polymorphic edge