Final answer:
Linkage disequilibrium in Ashkenazi Jews notably exists between disease alleles for BRCA1 and BRCA2 and nearby marker loci. The reduced recombination in this population maintains the non-random association of these alleles, which has implications for disease prediction and personal healthcare.
Step-by-step explanation:
Linkage disequilibrium refers to the non-random association of alleles at different loci that are typically inherited together due to their proximity on a chromosome.
In the context of Ashkenazi Jews, this population has been found to have a higher prevalence of certain disease alleles for BRCA1 and BRCA2 genes, which are linked to an increased risk for breast and ovarian cancers. These alleles are in linkage disequilibrium with nearby marker loci due to the low levels of recombination between these loci in Ashkenazi Jewish populations. Given the genetic linkage and the founder effect in Ashkenazi Jews, there is a reduced chance for these alleles to be separated by recombination, thus maintaining linkage disequilibrium. The use of genetic markers and linkage maps aids in disease prediction and risk management for affected individuals. Genome-wide association studies, such as the International HapMap Project, further support the identification of such linked genetic variations by correlating specific marker SNPs with the presence of disease-related genes.