Previous collaborations with Dr. Svetkey suggested evidence for linkage between a marker on chromosome 5, at or near the beta-2- adrenergic receptor, that was responsible, at least in part, for the phenotypic variation of diastolic blood pressure after salt loading and depletion. Additional genotyping of markers flanking the putative locus failed to show evidence of linkage, although the previous finding was corroborated using the variance- components method of linkage analysis. The estimated recombination fractions between the flanking markers were considerably larger in this population of predominantly female African-Americans than reported in other populations. Estimates of heritability suggest that at least some of the traits related to salt- sensitivity are high, suggesting that genetic components may play a substantial role in the expression of blood pressure after exposure to salt loading.
