Chromosome Studies on Bone Marrow from a Male Control Population

S ummary Chromosome analyses of bone marrow cells prepared by the direct method were carried out on 32 male patients, who had no primary haematological disease. One patient was found to have a pericentric inversion of the Y chromosome, which was also present in a skin fibroblast culture and in a lymphocyte culture. Three cases were found to have a high percentage of bone marrow cells with a 45 ,X chromosome constitution and one case had a 45 , X?Y ‐ or G‐ cell line. The high degree of aneuploidy was not found on examination of cells from leucocyte cultures. This observation is discussed in relation with other similar findings in patients with haematological diseases. The remaining 27 patients had a normal male karyo‐type and showed only small deviations from the modal chromosome number. The percentage of bone marrow cells with either chromatid aberrations or stable chromosome abnormalities was not significantly different from previous observations on lymphocyte cultures. However, the proportion of cells with unstable chromosome abnormalities was found to be substantially reduced in comparison with results from cultured lymphocytes examined in their first in vitro division.