The physical maps of the HSY and its corresponding X region with BAC clones on the minimum tilling path. Red lines represent individual BAC clone with clone ID on the top and estimated insert size at thebottom. Blue dotted lines indicate the overlap of neighboring BAC clones. K1 ~ K5 indicate the position of heterochromatic knob-like structures . Purple lines defined the borders of the non-recombination region genetically by fine mapping. SH: SunUp hermaphrodite BACs; SF: SunUp female BACs; AM: AU9 male BACs.