Final answer:
Linkage disequilibrium is associated with the co-inheritance of marker alleles at unusual frequencies. This can be explained by genetic phenomena that deviate from Mendel's laws, such as linkage, which results in alleles being inherited together more often when they are close on the same chromosome.
Step-by-step explanation:
The property associated with the co-inheritance of marker alleles at frequencies that deviate from that expected based on the allele frequencies is known as Linkage disequilibrium. Phenomena such as incomplete dominance, codominance, recessive lethals, multiple alleles, and sex linkage explain deviations from Mendel's model of inheritance by displaying inheriting patterns that do not conform to Mendel's laws of segregation and independent assortment.
Mendel's laws assumed genes segregate and assort independently, but this is not always the case. For instance, Thomas Hunt Morgan's work with fruit flies showed that genes that are physically close on the same chromosome tend to be inherited together because they are linked, reducing the frequency of recombination. Conversely, genes that are far apart on the same chromosome or on different chromosomes show Mendelian inheritance patterns because they undergo independent assortment or have a higher likelihood of recombination.
Genetic linkage is a critical concept in understanding heredity as it influences the expected ratios of offspring phenotypes. Linkage maps can be created by studying the frequency of crossing-over between genes, which provides insights into their relative positions on a chromosome.