Chromosome constitution of cells from human gingiva

This is a study of cells and chromosomes during serial transfer of tissue cultures, starting from the first mitosis occurring before explantation of normal gingival tissues and continuing until a genotypic variation was attained after explantation. From 16 specimens, 9 could be maintained in vitro for varying lengths of time, 7 for more than 50 weeks. In all cases, at 2 months in cultures and afterward, cells were found to be fibroblast-like cells with heteroploid chromosomal complement. The heteroploidy of the cells was due to extrasomy of chromosomes from all groups. However, chromosomes of the me cells before culturing showed the normal diploid number of 46 chromosomes.