Karyotypic abnormality of the X chromosome is rare in mutant HPRT- lymphocyte clones

P. Muir, Y. Osborne, A. A. Morley, D. R. Turner

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11 Citations (Scopus)


Lymphocyte clones mutated at the hypoxanthine-guanine phosphoribosyl-transferase (HPRT) locus on the X chromosome were studied by synchronization and G banding to determine the proportion of mutant clones having visible karyotypic change. 47 spontaneously mutant clones, 17 mutant clones induced by X-irradiation and 33 wild-type clones were studied. All clones were karyotypically normal except for 1 clone induced by X-irradiation in which an interstitial deletion of the short arm of the X chromosome had been inserted into the long arm of the same chromosome between q23 and q24; this change may have been coincidental or may have resulted in a position effect mutation. It was concluded that the great majority of mutations were not associated with a visible chromosome abnormality. This conclusion complements molecular studies which suggest that gene changes at the HPRT locus in HPRT- mutants generally extend over segments of DNA too small to be resolved by karyotypic analysis.

Original languageEnglish
Pages (from-to)157-160
Number of pages4
JournalMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis
Issue number1
Publication statusPublished - Jan 1988
Externally publishedYes


  • HPRT lymphocyte clones
  • Hypoxanthine-guanine phosphoribosyl-transferase locus
  • Karyotypic abnormality
  • X chromosome


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