For palindromic markers, the infinite allele method counts a difference for two types of changes: a mismatch and a copy number change.
Mismatches occur when the compared markers do not match. For example, the first man might have DYS464 = 14-15-15-16 and the other man might have DYS464 = 14-15-16-18. This counts as a single difference toward the two men’s genetic distance.
Palindromic copy number changes are when one male has more copies of the STR marker than the other male. For example, one man might have DYS464 = 14-15-16-17 and the other might have 14-15-15-16-16-17. This also counts as a single difference toward the two men’s total genetic distance.
When two men are compared and they show both a mismatch and a copy number change, it is counted as a genetic distance of two. For example, one might have DYS464 = 14-14-15-16 and the second person DYS464 = 14-15-15-16-16-17.