Pericentromeric structure of human X “isochromosomes”: evidence for molecular heterogeneity

✍ Scribed by Cecil B. Sharp; H. Melanie Bedford; Huntington F. Willard

• Book ID: 104664269
• Publisher: Springer
• Year: 1990
• Tongue: English
• Weight: 1000 KB
• Volume: 85
• Category: Article
• ISSN: 0340-6717
• DOI: 10.1007/bf00206757

✦ Synopsis

Three different long-arm X isochromosomes and an isodicentric X chromosome were examined by in situ hybridization with X-chromosome-specific alpha-satellite probes and by quantitation of Southern blots hybridized with proximal short-arm probes. Each chromosome had a unique pericentromeric structure. The isodicentric X chromosome was clearly dicentric, showing two distinct alpha-satellite hybridization signals and duplication of short-arm material. Two isochromosomes showed a larger than normal, bifid alpha-satellite signal and also had duplications of different extents of short-arm material. The third X isochromosome could not be distinguished from a classical long-arm isochromosome; it did not have a short-arm duplication and it had a single alpha-satellite signal. These data indicate that rearrangements responsible for X isochromosome formation can occur at numerous locations in the pericentromeric region and that some X isochromosomes may involve duplications of substantial portions of the short arm.