Population genetic analyses of susceptibility to developing alcohol dependence

Abstract

Acting on the assumption that susceptibility to alcohol dependence is genetically controlled, we have developed a hypothesis that a generally increased homozygosity level, as well as a changed variability in the group of alcoholics, could be a population genetic parameter for predicting this dependence. A morphophysiological test was used to identify the proportion of homozygously recessive characteristics (HRC test), so that the comparison of presence and distribution of the 25 selected homorecessive traits was carried out between the group of 100 cured alcoholics (the A group), and a control group consisting of 100 non-alcoholics (the C group). This population genetic study revealed not only a statistically significant difference in the mean values of genetic homozygosity (A: 9.3 ± 0.2, C: 8.2 ± 0.2), but also the differences in the distribution type, as well as in the variances of presence of certain specific combinations of such traits. In 18 of the 25 observed characteristics, recessive homozygosity was expressed to a greater degree among the group of alcoholics, while for 10 of the traits this level of difference was statistically significant. The fact that the genes controlling such qualitative recessive traits are distributed in different human chromosomes as their visible markers, could indicate that the genetic homozygosity degrees are visibly higher in the sample of alcohol dependents when compared to the group of individuals free from such dependence. Further application of the HRC testing as an easy procedure may have its practical use in identifying the presence of such indicators in young individuals in order to detect a possible future inclination to alcoholism.