Fig. 1

Ordering of recombination matrix. The three stages of ordering (a, b, c) visualized with the pairwise recombination frequency matrix. Each row and column represents one marker. Dark and light shades of grey indicate low and high recombination frequencies, respectively. a) The markers are in random order. The diagonal is dark because the recombination frequency of a matrix with itself is zero. b) The markers are ordered according to their linkage groups. Seven separated rectangles are formed and easy to distinguish. c) The markers are ordered within each linkage group. Most of the low values moved to the diagonal