[Polymorphism of group specific component (Gc) in nine Han subpopulations in China]

Isoelectric focusing (IEF) followed by immunofixation in thin layer polyacrylamide gels (pH4-6) was used to analyse the Gc subtypes of 1841 individuals from nine Han geographically distributed populations in China. The Gc1F gene frequencies in these Han subpopulations from Lanzhou, Huhhot, Harbin, Xi'an, Zhengzhou, Chengdu, Guiyang, Zhangzhou and Harras in Guangdong Province were 0.3905, 0.4333, 0.4193, 0.4146, 0.4182, 0.4035, 0.4045, 0.4381 and 0.4347 respectively; Gc1S were 0.3071, 0.2190, 0.2734, 0.2261, 0.2182, 0.2871, 0.2889, 0.2738 and 0.2764 respectively; Gc2 were 0.2786, 0.3357, 0.2917, 0.3367, 0.3295, 0.2896, 0.3065, 0.2667, and 0.2814 respectively. GcV were 0.0238, 0.0119, 0.0156, 0.0226, 0.0341, 0.0198, 0.0000, 0.0214 and 0.0075 respectively. The results of present study indicated a clear cline of linear change from north to south China in allelic frequency at the Group-Specific Component (Gc) locus among nine Chinese populations. Three alleles, Gc1F, Gc2 and GcV, showed frequencies varying from 0.3905 to 0.4381, from 0.2786 to 0.3367 and from nil to 0.0341, respectively, over these geographical subpopulations. In addition, some rare variant phenotypes of Gc in Chinese populations were discussed.