Estudio de paternidad aplicando el polimorfismo de DNA: evaluación en relación a los métodos convencionalmente usados en Chile / Paternity study applying DNA polimorphism: evaluation in relation to conventional methods used in Chile

RESUMO

Simultaneous detection of several VNTR loci using a single DNA probe is the basis of the technique called DNA fingerprint (DNAfp) of increasing application in parenthood identification. According to the data gathered by different laboratories worldwide, father exclusion can be made in a larger number of cases when compared with the customary tests based on erythrocyte antigens. The question could then be whether DNAfp will completely replace erythrocyte antigen tests. We report here our experience in applying DNAfp to 92 samples corresponding to 34 paternity cases and comparing these with the results obtained with the antigens of the systems ABO, Rh. MNSs, Duffy and Kidd. Most of the HaeIII/digested DNA samples produced 13 to 16 bands larger than 4,3 Kb (average 14,0761ñ2,205). Average band sharing between pairs of unrelated individual was 1,907ñ1,083. Two cases presenting an a posteriori probability of being the father of 80.7 percent and 76.5 percent by erythrocyte antigens were clearly excluded by DNAfp. All exclusions made by antigens were confirmed by DNAfp. In the cases reported as father probable (28 cases) by DNAfp, these shared with the child 6,7407ñ1,7 bands on average. Because of time, cost and simplicity we favor a procedure starting with the antigens test and continuing with DNAfp only when an exclusion is not possible. Economy will increase as the number of exclussions increases