Aneuploid cell percentages and frequencies of CAs and SCEs were investigated in 10 Calabrian pigs, 10 LW pigs and 19 Calabrian x LW crossbred pigs, in order to compare genome stability between an autochthonous pig breed and a highly selected one and to verify if genome stability of their progeny, as other phenotypic traits, are influenced by heterosis. The mean number of cells per animal with structural aberrations, excluding gaps, was 6.20 +/- 2.39, 4.90 +/- 2.02 and 4.52 +/- 3.34 in Calabrian, LW and crossbred pigs, respectively, while the mean number of total CAs without gaps was 0.14 +/- 0.38, 0.11 +/- 0.35 and 0.11 +/- 0.35, respectively. The mean number of SCEs was 7.30 +/- 3.24 in Calabrian pigs, 6.45 +/- 2.74 in LW pigs and 6.28 +/- 2.90 in the crossbred ones. Percentages of cells with aneuploidy were 7.30, 10.10 and 10.79 in Calabrian, LW and crossbred pigs, respectively. In particular, the Calabrian breed showed higher values compared to LW in each test, however, there were statistically significant differences only in the mean number of SCEs per cell (P<0.01). In addition, there is a positive effect of crossbreeding on baseline levels of genome stability in the crossbred group that shows in all tests, excluding gaps, mean values of cellular or chromosome damage similar to the LW group.