ASYMMETRY OF CHROMOSOME NUMBER 1 PAIR IN THREE GENERATIONS OF A PHENOTYPICALLY NORMAL FAMILY

Authors:
  • KYKuang-Lin Ying
    Kuang-Lin Ying
  • EIElizabeth J. Ives
    Elizabeth J. Ives
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Abstract
A family is reported in which 6 of the 15 members studied carry a greatly lengthened #1 chromosome. This has segregated in three generations without phenotypic effect.Blood grouping provides evidence in favour of linkage of the Duffy locus and #1 chromosome.Autoradiographic studies demonstrate that DNA replication in the extended region of the marker chromosome occurs late in the majority of cells but early in a small proportion of cells in each of the three individuals thus studied. Possible explanations discussed include environmental modifications in culture technique, an unstable replication pattern in the extended region, and the chance that somatic crossing over of homologues allows a shift of a hypothetical "genetic inactivation centre" from one chromosome to the corresponding region of its homologue.