[Swine cell sublines with different ploidies. I. Karyotypic evolution].
Two swine kidney cell sublines, one of them IB-RS-10-I, with diploid level of chromosomes and the other, IB-RS-10-II, with tetraploid level, were studied as far as their morphology and karyotypic evolution was concerned. Both of them derived from the parental cell line after seven months in continuous culture and maintained in the same type of nutrient medium showed peculiar chromosome alterations for each subline, though in both sublines were observed losses of chromosomes belonging to the gruop GIV.