RESUMO
Objective To understand the molecular genetic basis of Ael subgroup of ABO blood group system in the Han nationality.Method 2 Ael individuals were defined by standard blood group serological techniques,and genomic DNA was prepared for PCR SSP genotyping.Primers were designed and synthesized to amplify complete exon 6 and 7 including flanking intron sequence,and direct sequencing of gel purified PCR amplified fragments was performed using Bigdye Sequencing kit.Result A possibility of regarding the Ael allele as A2,B,O1 and O2 genes had been eliminated by the PCR SSP assay.According to the sequence analysis,Ael gene had 2 mutations of which one was a nucleotide substitution at position 532 in intron 5 (C to T),and the other was a single nucleotide(G) insertion at position 798 to 804 in exon 7 which alter the 86 amino acids sequence of the glycosyltransferase and furthermore extend the translated proteins by 37 amino acids compared with A1 allele.Conclusion The mutations of (789 804)G insertion and C(I 5/532)T substitution is the molecular genetic basis for Ael phenotype.