Ideogram of the distribution of DAPI-bright regions on rice pachytene chromosomes. The ideogram was generalized based on observations in 50 pachytene cells. Each circle represents a distinct DAPI-bright region that is consistently observed in the majority of the pachytene chromosomes. Shaded circles represent the DAPI-bright regions observed in indica rice Zhongxian 3037 but not injaponica rice Nipponbare. Open circles represent the location of the centromeres. The dotted line on the top of chromosome 9 represents the rDNA section. The relative length of each chromosome and the arm ratio were drawn based on Table 2 data.