The 116 breakpoints (bps) involved in 58 reciprocal translocations are being mapped. Of 73 A-genome bps, 71 have been mapped to their arms, at least one in each of the 26 arms. For 61 of these, the distance from the centromere has been determined. Forty-one of the 43 D-genome bps have been assigned to arms and 19 have been located relative to their centromeres. Eight D-genome arms lack bps; two of these (23L and 24L) are not represented by any other chromosome marker. Duplication-deficiencies have been generated and characterized from 34 of the 58 lines. Schemes for using duplication-deficiencies to map genes are outlined.