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The Barr body is a looped X chromosome formed by telomere association
C L Walker1, C B Cargile, K M Floy
1Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Abstract:
We examined Barr bodies formed by isodicentric human X chromosomes in cultured human cells and in mouse-human hybrids using confocal microscopy and DNA probes for centromere and subtelomere regions. At interphase, the two ends of these chromosomes are only a micron apart, indicating that these inactive X chromosomes are in a nonlinear configuration. Additional studies of normal X chromosomes reveal the same telomere association for the inactive X but not for the active X chromosome. This nonlinear configuration is maintained during mitosis and in a murine environment.