T-CELL RECEPTOR-BETA CHAIN RFLP IN CHINESE, INDIANS AND MALAYS FROM SINGAPORE

Restriction fragment length polymorphism (RFLP) of the gene encoding t he beta chain of the human T cell receptor (TcR) was studied in three ethnic groups in Singapore by Southern blotting. Polymorphism in the b eta chain gene was identified in BglII-digested DNA samples using a 77 0-bp TcR beta cDNA clone containing the joining and constant region se gments. The TcR beta/BglII polymorphism was studied in 136 Chinese, 93 Indian and 88 Malay samples. The frequency of the less frequent allel e (TcR beta2) in all the ethnic groups was significantly lower (0.15- 0.29, p < 0.01) than that in the Caucasians (0.46). Indians had a sign ificantly lower frequency of this allele (0.15) than the Chinese (0.29 ) and Malays (0.26).