Normal human metaphase chromosomes isolated from fibroblasts were resolved into 14 peaks based on total Hoechst 33258 fluorescence and sorted with the flourescence-activated cell sorter. The chromosomal DNA was extracted and characterized by EcoRI analysis. As expected, analysis of the peak containing chromosomes 16 and 18 detected the α-globin genes and of the peak containing chromosomes 9, 10, 11 and 12 detected the β-, γ, and δ-globin genes. Translocations were then used to localize further the β-, γ-, and δ-globin genes. The first translocations t(11;22)(q25;q11) which moved nearly all of chromosome 11 to a different peak, confirmed that the β-, γ-, and δ-globin genes are on this chromosome. The second, t(4;11)(q25;q13), which moved the distal portion of the long arm of chromosome 11 to a new peak, showed that the genes are not in this segment. The third, t(X;11)(q11;p13), moved the distal region of the short arm of chromosome 11 to a peak which now contained the β-, γ-, and δ-globin genes. Therefore, the β-, γ-, and δ-globin genes reside on the distal portion of the chromosome 11 short arm including bands p13, p14, and p15. This sorting method may be used generally to assign other genes to chromosomal segments of the entire chromosome complement.
