Aims: This study aimed to compare the intron 4 sequence of the RHD and RHCE genes from Han Chinese, Tibetans, and Mongols, and explore its polymorphisms.
Materials and methods: To investigate the distinction in the RHD and RHCE intron 4, polymerase chain reaction (PCR) was performed by a set of primers: Intron4F and Intron4R. Primer Intron4F for a sequence located in exon 4 and primer Intron4R for a sequence located in exon 5, respectively. RHD and RHCE intron 4 of all the samples from 26 cases of random unrelated Hans (13 RhD-positive donors and 13 RhD-negative donors), 25 cases of random unrelated Tibetans (18 RhD-positive donors and 7 RhD-negative donors), and 4 cases of random unrelated Mongols (1 RhD-positive donor and 3 RhD-negative donors) were amplified with PCR. The PCR products were then sequenced.
Results: A 576-bp product was detected in all the Han, Tibetan, and Mongol RhD-positive donors, whereas a 1228-bp product was detected in RhD-negative donors. The sequences of RHCE gene intron 4 were identical to each other in all Han, Tibetan, and Mongol RhD-negative donors, including 335 bp of Alu element, with a whole length of 1078 bp. By contrast, a 426-bp product was detected in all Han, Tibetan, and Mongol RhD-positive donors. Compared with the RHCE gene, a 652-bp deletion was noted in the RHD gene of Chinese, including the whole Alu element. The results were similar to the findings of Caucasians, whereas the lengths of RHD gene deletion fragments of Japanese and French were 649 and 654 or 651 bp, respectively.
Conclusions: The RHCE gene intron 4 of Han Chinese, Tibetans, and Mongols differs from the RHD gene intron 4 in the presence of a 652-bp fragment. The RHCE gene intron 4 in Chinese has its own structural characteristics and differs among various ethnicities and regions.