Fine genetic linkage maps of DIP in T. officinale. (A) Map redrawn from Vijverberg et al. , based on 73 plants, 34 AFLP- and two Mst-markers, with minor updates (16, this study). The regular distribution of markers over the DIP-chromosomal region suggests the absence of suppression of recombination. (B) Map based on 300 plants and five PCR markers. The marker distribution is congruent with the absence of suppression of recombination and lacks evidence for the presence of a 'cold spot', a non-recombining region at the Mst loci. (C) Map based on the 24 recombinants between S8 and S10 out of 2227 plants tested and the six AFLPs known in this region. Markers closest to DIP are S7 at 0.4 cM at one flank and a cluster of three AFLPs, including S10, at 0.2 cM at the other flank, spanning a total of 0.6 cM. A1 to A9 denote AFLP-clusters according to manual sorting, and S3, S4, S7 to S11 denote sequence characterized regions.