Cultured adipose-derived mesenchymal stem cells retain their diploid state, in contrast to bone marrow mesenchymal stem cells that become polyploid. Independent preparations of paired (A) adipose-derived mesenchymal stem cells (ASCs) and (B) bone marrow mesenchymal stem cells (BM MSCs; prepared from the same male or female mouse), were expanded in Mesencult and their DNA content was analyzed by flow cytometry, diploid (2N) and tetraploid (4N). Resulting plots from male/female ASCs/BM MSCs were overlaid and are presented in a single graph; six female and six male adipose-derived mesenchymal stem cells and six female and five male BM MSCs were used. (C) Chromosome spreads were made from three adipose-derived mesenchymal stem cells and three BM MSC preparations and a graphic summary of the median (straight short line) chromosome count is shown (10 to 15 different metaphases were counted from each cell preparation). Horizontal dashed lines, diploid or tetraploid DNA contents at chromosome numbers 40 and 80, respectively. (D) Examples of the 4',6-diamidino-2-phenylindole-stained chromosomes from a single preparation of adipose-derived mesenchymal stem cells and BM MSCs as summarized in the previous section.