The fusion gene at the ABO-secretor locus (FUT2): absence in Chinese populations.

The fusion gene (se(fus)) is a null allele of the secretor type alpha (1, 2) fucosyltransferase gene (FUT2) and was first found in a Japanese population. It has not yet been reported in any other ethnic population. In the present study, we investigated the distribution of the fusion gene of the FUT2 locus in five populations from three ethnic groups in East Asia. The fusion gene was found in two additional Japanese populations with a high frequency (0.0551 in Okinawa and 0.0792 in Akita) and, for the first time outside Japan, in a Korean population, at a very low frequency (0.0063 in Seoul). In contrast, we found no fusion gene in two Chinese populations. These findings showed that the FUT2 fusion gene was ubiquitous in Japanese, but was rare in neighboring populations, suggesting that the FUT2 fusion gene had emerged from within the Japanese. Additionally, a new null allele with a C-to-T substitution at nucleotide 658 was found in one individual native of southern China.