Two articles in the June issue of Nature Methods describe tools for the detection of large-scale structural rearrangements in individual chromosomes. Every individual human genome is peppered with sequence variations, and numerous techniques are available for scientists hoping to analyze these differences. But genomes can harbor far more dramatic variations, such as the translocation of fragments from one chromosome to another or the inversion of a segment of chromosomal DNA. These alterations can have dramatic consequences for cellular health, but until recently, few tools were available for detecting them.
In cells in which a nonreciprocal translocation has taken place, a chromosome segment is replaced by a segment from a different chromosome, resulting in a change in copy number for certain marker sequences. Terence Rabbitts and his colleagues take advantage of this with a method called “molecular copy-number counting,” which allows them to precisely zoom in on breakpoints where a translocation has occurred by amplifying various chromosomal markers and quantifying changes in copy number.
Inversions often occur in the midst of large stretches of repetitive DNA sequence, making analysis difficult, but Matthew Hurles and his colleagues have found a way around that. They describe an assay that allows investigators to quickly diagnose the status of potential sites of chromosomal rearrangement by detecting sequence changes at likely breakpoints.
These tools promise to help fill a void in the current genomic research toolbox, and Andrew Sharp takes a closer look at their potential value in an accompanying News and Views piece.
Terence H. Rabbitts (MRC Laboratory of Molecular Biology, Cambridge, UK)
Matthew E. Hurles (Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK)
Andrew Sharp (University of Washington, Seattle, WA, USA) News and Views author
Abstracts available online:
(C) Nature Methods press release.
Message posted by: Trevor M. D'Souza