The dimorphism in human normal cerumen.

Abstract

SummaryVarious aspects of the dimorphism in human cerumen have been described on the basis of the data collected mostly by Japanese investigators. It was shown that the ear‐wax types are apparently determined by a simple genetic mechanism, and can be used as a polymorphic system for both genetics and anthropology. Frequencies of the alleles for the ear‐wax types have been estimated for different ethnic groups. It was pointed out that the marked difference in the distribution of ear‐wax types among the major races is probably a consequence of natural selection having acted in a long course of evolution, and there may be some differences in the selective value between individuals with wet cerumen and those with dry. In view of the apparent association with axillary odour, it was suggested that the alleles for ear‐wax types may control certain metabolic processes, through which individuals with different types of oerumen may display different reactions to environmental changes. The need for future studies along this line is stressed.