Ratio of actual over expected frequencies (based on marginal frequencies) of interactions (mfDCA) between different sequon related positions.

The interactions are distributed unevenly (X2, p<0.001). As expected there is a preference to N-S/T relationship obviating the epistatic link in the individual sequons. Further, variable sequons are related mostly to themselves forming cliques in the variable loops. The preference of frequent for rare N positions indicates that the rare sequons may be often variants of the frequent. At the same time S/T positions of variable sequons are related also to N positions of rare sequons.

相互作用的分布并不均匀（X²检验，p<0.001）。正如预期，样本对天冬酰胺-丝氨酸/苏氨酸（N-S/T）关联存在偏好，这一偏好消除了单个糖基化位点（sequon）内的上位性关联。进一步分析发现，可变糖基化位点大多与其自身形成关联，在可变环中构成完全子图（clique）。高频N位点相较于低频N位点的偏好性表明，低频糖基化位点往往是高频位点的变异体。与此同时，可变糖基化位点的丝氨酸/苏氨酸位点，也与低频糖基化位点的天冬酰胺位点存在关联。