Mathematical model for satellite associations of human acrocentric chromosomes.

Short arms, satellite stalks and satellites of human acrocentric chromosomes (13, 14, 15, 21 and 22) represent heterochromatic regions. Enforced by mutual attraction of heterochromatic regions, the short arms of acrocentric chromosomes come close to each other and compose associations. The associations of human acrocentric chromosomes cause nucleolus formation, undergo age-related changes, account for elevated incidence of chromosome rearrangements and, consequently, can cause chromosome diseases. Most acrocentric chromosome associations are formed by chromatid satellite stalks. This work contains results of acrocentric association rates assessed with use of newly designed mathematical model, which is based on two parameters: the probability of formation and the association intensity for different acrocentric chromosome pairs. For middle-aged individuals the following values were defined: S(0) = 0.558, lambda(V) = 0.2706, lambda(V) = 0.4768 and lambda(W) = 0.0960. The new mathematical model for satellite associations makes it possible to compare two cells not only by the total number of acrocentric chromosome associations, but also by the type and character of each association.