Population genetics of connexin 26 deafness

The researchers aim to explore three explanations for the high genetic prevalence and mutational diversity of deafness-causing GJB2 mutations in the North American population, as well as the association of specific GJB2 mutations within ethnic groups.

One possibility is mutation-selection equilibrium: novel GJB2 mutations are perhaps being introduced at the same rate that mutations in the gene pool are being eliminated. Evidence showing a mutational hotspot at GJB2, particularly for deletion mutations, would provide support for this hypothesis.

A second explanation is linguistic homogamy: in this case, culturally deaf individuals have actively sought mates with compatible fluency in signed languages. This mate-selection phenomenon may have begun ~200 years ago with the introduction of signed language in residential schools for the deaf.

A third possibility is that of balancing selection: unrelated to studying deafness, Tran van Nhieu, Clair et al. have shown in tissue culture experiments that Shigella flexneri requires GJB2 connexons for egression into the intestinal epithelia, raising the possibility that the three common GJB2 deletions could confer resistance to Shigella dysentery.

This project studies all three of these hypotheses.