Final answer:
Linkage disequilibrium affects Hardy Weinberg calculations by causing observed genotype frequencies to deviate from expectations, as it violates the principle's assumption of random allele assortment. This impacts the principle's accuracy in predicting allele frequencies and identifying microevolutionary changes within a population.
Step-by-step explanation:
The consequence of linkage disequilibrium for Hardy Weinberg calculations is significant because it involves the non-random association of alleles at two or more loci, not conforming to the expected genotype frequencies. The Hardy-Weinberg principle presupposes that alleles are assorted independently and recombine randomly, conditions necessary for equilibrium and reliable predictions of allele frequencies within a population. However, linkage disequilibrium disrupts these expectations.
Practically, linkage disequilibrium can result in the observed genotype frequencies that deviate substantially from those predicted by the Hardy-Weinberg equation, which assumes no linkage between alleles. For instance, if alleles are physically close on a chromosome, the recombination frequency is reduced, and certain allele combinations can be inherited together more frequently than expected by chance. This reduces genetic diversity and distorts the prediction accuracy of the Hardy-Weinberg principle, impeding our ability to use it as a baseline to detect microevolutionary changes.
As populations are in flux due to various evolutionary forces such as genetic drift, mutation, migration, and natural selection, the presence of linkage disequilibrium is a clear indicator that the population is not in Hardy-Weinberg equilibrium and is, therefore, evolving.