Abstract: The distribution of cerumen types in seven ethnic groups, as well as Han nationality from two different regions, was examined on total 1571 subjects. The gene frequency of dry cerumen in Mongolian (Inner Mongolia) is 0.9323; Hani (Yunnan) 0.8091; Jingpo ( Yunnan) 0.7769; Dai ( Yunnan) 0.7071; Achang (Yunnan) 0.6810; Deang (Yunnan) 0.5928; Buyi (Guizhou) 0.6834; Han (Inner Mongolia) 0.9817 and Han (Fujian) 0.8971. The genetic differentiation among the populations in China was studied using data on cerumen dimorphism in different Chinese ethnic groups collected from available sources. The fixation index Fst is equal to 0.22, which indicates an extremely great differentiation in cerumen gene frequencies when compared with those of other loci.
The distribution of dry cerumen gene frequency on the world shows that some populations in northeast Asia, including Han in North China, have the highest gene frequency and it declines in all directions to other regions. It suggests that the dry cerumen gene was originated by a mutation in northeast Asia long long ago when Mongoloid was just formed and today's distribution of cerumen gene frequency in the world is mainly a result of gene diffusion rather than that of salection.

Key words: Cerumen; Gene frequency; Human population genetics