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Can sister chromatid intercrossings be considered as prelesions?

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In a study of the expression of folate-sensitive fragile sites in five normal individuals using RPMI medium containing methotrexate (MTX), we observed a high frequency of “sister chromatid intercrossings” (SCI) that is, the intersection of sister chromatids. The location of SCIs corresponded to fragile sites in 54.2% of the cases. Of the SCIs observed in each individual, 43%–53% were located at the same bands as their expressed fragile sites. Furthermore when RPMI+MTX medium was used instead of F-10 medium, the incidence of SCIs increased tenfold. We suggest that SCIs could indicate the existence of a pre-lesion.

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Correspondence to Carme Fuster.

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Fuster, C., Mirò, R., Templado, C. et al. Can sister chromatid intercrossings be considered as prelesions?. Hum Genet 79, 179–180 (1988). https://doi.org/10.1007/BF00280561

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  • Internal Medicine
  • Methotrexate
  • Metabolic Disease
  • RPMI Medium
  • Normal Individual