Figure 1 .

(A) Genetic and physical map of the sex-determining regions on the X and Y chromosomes. 1, normal XY male; 2, XX female; 3 and 4, recombinant male. Blue column, regions derived from the Y chromosome; red, from the X chromosome. Red bar, BAC clones; blue bar, fosmid clones. Black arrows indicate predicted genes. (B) RT–PCR products of PGs (PG1–9) in the XX and XY body trunk at 0 days after hatching. M, size marker.