an example of absolute LD, where the two polymorphisms are completely correlated with one another. An instance when absolute LD can develop is when two linked mutations occur at a similar point in time and no recombination has occurred between the sites. In this case, the history of mutation and recombination for the sites is the same. Other processes, such as genetic drift, can produce similar patterns, as discussed below. Both r2 and D0 have a value of 1 in this scenario.