Blood group genetic studies in an urban Chinese population.

The distribution of the blood group systems ABO, Rhesus, MNSs and P was studied in all or some of 1,007 Singapore Chinese, ABO gene frequencies were found to be consistent with previous studies and did not vary significantly between dialects. An individual of phenotype A2B was detected although the population showed no other evidence for the A2 gene. The possible significance of this observation in terms of weak H alleles in the population is discussed. The frequencies of the MNSs genes are consistent with previous studies. Two subjects appeared to lack the NA component of the N antigen. The frequency of the R1 gene of the Rhesus system was lower than has been detected previously and may relate to dialect differences. No examples of the CW antigen were detected. The P blood group distribution appears to be subject to regional variation. It is concluded that classification of Chinese into dialect groups is a useful way of assessing genetic heterogeneity.