Leukaemia cytogenetics / H. Jackson Woodliff.

  • Woodliff, H. Jackson.
Date:
1971
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Leukaemia cytogenetics / H. Jackson Woodliff. Source: Wellcome Collection.

    41/168 (page 25)
    NORMAL HUMAN CHROMOSOMES 25 by Hamerton et al. (1965). Aneuploidy in the female was around 4-6 per cent up to the age of 54; thereafter it was more than 10 per cent. Analysis showed that in the hypodiploid metaphases some chromosomes are more frequently absent than in others and in females the most common hypodiploid line was 45 C-; it was concluded that the missing chromosome was an X. The age change in males was less marked but there was evidence of an increasing loss of one of the G-Y chromosomes and this was more often identified as a Y. Sandberg et al. (1967ö) using blood samples from an unselected population confirmed that hypodi- ploidy was increased in females but only above 65 years of age; they found no significant hypodiploidy in males. Occasional polyploid metaphases (0-5 per cent) may also be found in cells from normal cultures and chromatid gaps and breaks in up to 4 per cent (Nasjleti and Spencer, 1968). Bone marrow metaphases generally show a greater degree of aneuploidy than those prepared from peripheral blood cultures; possibly because they are more difficult to prepare there are more artefacts (Ford, 1959). Short-term cultures of bone marrow from 10 normal subjects contained about 15 per cent aneuploid meta¬ phases but less than 3 per cent were hyperdiploid (Court Brown et al., 1960). Sandberg et al. (1960) using a direct method studied cells from 10 subjects and found on average that 8 per cent of the cells were hypodiploid and 2 per cent hyperdiploid, later (Sandberg et al, 1961) a figure of 12-2 ± 0-8 per cent was given. In our laboratory, aneuploidy ranges from 0 to 20 per cent were obtained with a mean of 9-6 per cent. Our arbitrary normal is up to 10 per cent and we are suspicious if 11 per cent are more aneuploid, especially if more than 3 per cent are hyperdiploid (Onesti and Woodlifif, 1968). Morphological variations may occur in up to 3 per cent of adults. Common changes are lengthening of the short arm of an acro¬ centric chromosome in groups D or G, and variation in the size of the Y chromosome. A smaller number (0-5 per cent) of structural changes in the autosomes may be found in normal adults (Court Brown, 1967).