Acción de la 5'azacitidina en cromosomas de células linfocitarias de bovinos

azacytidine (5-azac) is a substance that inhibits the metilation of dna, being used in cloning experiments, nuclear transference transgenesis and in chromosomal fragility studies. the manifestation of diverse pathologies has been observed in domestic animals born from cloning experiments. these would be associated to an incorrect nuclear reprogramation related to epigenetic metilation phenomena of the dna. in the present work an induction curve with different final concentrations of 5-azac (0 um, 5 um, 10 um, 20 um, 50 um and 70 um) were carried out, with the objective of studying the effects on chromosome structure in bovine lymphocyte cultures. the macroculture technique was used for chromosomic analysis, from a blood sample of a male bovine (bos taurus, holstein friesian). a total of 50 metaphases were analyzed from each culture. significative differences (p<0.01) were found regarding the break points of chromosome x in the control culture with respect to the culture with higher concentration of 5-azac. chromosome y did not show break points. the cultures with higher concentration of 5-azac (50 um and 70 um) presented chromosomic decondensation (12% and 16%) and autosomic centromeric break points (2% and 4%).