Figure 2.

Gene order relationships for a representative linkage group (LG2) between two parental sunflower species, H. annuus and H. petiolaris, and their three diploid hybrid derivatives, H. anomalus, H. deserticola, and H. paradoxus. Note the fission of LG2 in H. paradoxus and the fusion of linkages 2 and 8 in H. anomalus and H. petiolaris. Markers beginning with ORS are simple sequence repeats (SSRs), those beginning with AFP are AFLPs, and those beginning with RPD are RAPDs. Markers followed by species names in parentheses (ann, annuus; ano, anomalus; par, paradoxus; and pet, petiolaris) are informative and map to the same linkage group in the listed species. Informative loci on adjacent linkage groups are also connected by lines. Numbers to the left of each linkage group refer to genetic distance (centimorgans). Single arrows indicate the location of inferred chromosomal breakages/fusions that are necessary to account for the differences between this map and that of H. annuus (Figure S4 at http://www.genetics.org/supplemental/). Letters (A and B) following some linkage group designations indicate fragmented linkage groups, with fragments homologous to the top of the H. annuus linkage group designated A, the next highest fragment labeled B, and so forth.