Two arrangements of the human fetal globin genes may be responsible for high G gamma values in Chinese newborns: -G gamma-G gamma-delta-beta and -G gamma-A gamma G gamma-A gamma-delta-beta.

High G gamma values (78% and higher) have been observed in about 3% of Chinese newborns from the Shanghai area. We describe here two arrangements different from the normal -G gamma-A gamma-delta-beta arrangement which have been characterized in the DNA from three of these babies. One baby was heterozygous for a chromosome with two linked G gamma globin genes (-G gamma-G gamma-delta-beta), which has also been observed in Black newborns [Powers et al, Nucleic Acids Res 12:7023, 1984], while the two other babies were heterozygous for a chromosome with triplicated gamma globin genes, presumably of the -G gamma-A gamma G gamma-A gamma-delta-beta arrangement. A similar triplication has been observed in natives of the New Hebrides [Trent et al, Nucleic Acids Res 9:6723, 1981].