A practical metaphase marker of the inactive X chromosome

D. L. van Dyke, W. L. Flejter, M. J. Worsham, J. R. Roberson, J. V. Higgins, H. M. Herr, S. Knuutila, N. Wang, V. R. Babu, L. Weiss

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


It is paradoxical that the inactivated X is the only chromosome that can be identified in the interphase nucleus, yet in metaphase, it is indistinguishable from its genetically active homolog unless special culture and staining procedures are employed. A specific inactivation-associated fold in proximal Xq resolves that paradox. We describe here how the fold in the proximal long arm can be used as a simple and reliable marker to identify the inactivated X in G-, Q-, or R-banded preparations. Several examples are given, including localization of the inactivation center to band Xq13 or q21.1, identification of nonrandom inactivation in X-chromosome rearrangements, identification of multiple active X chromosomes in tumor cell lines, analyis of X-inactivation patterns in female carriers of the fragile site at Xq27, and comparison of X-inactivation patterns among primate species.

Original languageEnglish (US)
Pages (from-to)88-95
Number of pages8
JournalAmerican journal of human genetics
Issue number1
StatePublished - 1986

ASJC Scopus subject areas

  • Genetics(clinical)
  • Genetics


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