Simple repeats are not found more abundantly at G/C-rich regions

✍ Scribed by Dr. Georg Melmer

• Book ID: 102183176
• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 183 KB
• Volume: 13
• Category: Article
• ISSN: 0173-0835
• DOI: 10.1002/elps.11501301131

✦ Synopsis

Simple repeats are not found more abundantly at G/C-rich regions

Three hundred and fifty cosmids from chromosome 7, previously analyzed for the presence of rare-cutting restriction enzyme sites, were analyzed for the presence of microsatellite sequences [(CA), or (CT), repeats]. Of these, 147 cosmids were found to contain at least one (CA), repeat unit and 51 cosmids contained at least one (CT), repeat unit. No evidence was found for the prevalence of microsatellite repeat units in the vicinity of rare-cutter restriction enzyme sites.

Restriction length polymorphisms are powerful tools for the localization of disease genes by the process now called reverse genetics [l]. However, because of the low degree of information these markers exhibit, they will be of limited use for genetically more complex diseases. Minisatellites, which are comprised by a varying number of tandem repeats (VNTR) are much more informative but they appear to be concentrated mainly at telomeres, [3] making them of limited use for linkage analysis. A subclass of this tandemly repeated DNA contains short and simple sequence repeats such as (CA), or (CT),. These microsatellites are thought to be present in the human genome in about 50000 copies . The (CA), repeats can adopt the Z-DNA conformation and it has been speculated that this conformation is involved in the regulation of gene expression . It would therefore not be surprising to find that microsatellites are more abundant in the vicinity of genes. This view was supported by the first reports of polymorphic (CA), repeats close to genes, such as the B-globin gene cluster [61. However, this finding might reflect that these repeats could be found by simply inspecting published sequences.