Investigations involving theoretical analyses, computer simulations, and analyses of molecular data have been conducted to determine the feasibility of obtaining genetic information from certain types of data. We have shown how to estimate average heterozygosity from DNA fingerprinting data such as that obtained by our own laboratory. We are also taking a novel approach toward human genetic linkage studies, focussing on population-level linkage disequilibrium rather than on more traditional family studies. The key aspect of the linkage disequilibrium study is that we are focussing on human populations that have a recent (i.e., on the order of a few hundred years) history of racial admixture. It is well known that racial admixture will create gametic disequilibrium for many genes, measurable by exactly the same statistics used to measure linkage disequilibrium. Much of this disequilibrium will be spurious from the standpoint of true physical linkage, but it is expected to decay at a rate dictated by the recombination rate. Hence, after a few generations, any remaining disequilibrium is expected to be due to true physical linkage. We are investigating the relevant parameters in hope of optimizing gene mapping efforts that could make use of this particular strategy. Initial results indicate that this strategy could be a powerful adjunct to the more traditional strategy of mapping genes by their segregation in pedigrees. We are also interested in evaluating this strategy as an approach toward mapping genes in which family data is scarce or less meaningful, such as genes relevant to virus, parasite, or other opportunistic infections in which environmental exposure is a key factor.
