Length of androgen receptor-CAG repeats in fertile and infertile Egyptian men.

Androgens play key roles in spermatogenesis, and they exert their effect via the androgen receptor (AR). The AR gene has a repetitive DNA sequence in exon 1 that encodes a polyglutamine tract. Instability in the glutamine (CAG) repeat unit length is polymorphic across ethnic groups.

A novel method for biodosimetry.

Accurate methods for measuring the biological effects of radiation are critical for estimating an individual's health risk from radiation exposure. We investigated the feasibility of using radiation-induced mutations in repetitive DNA sequences to measure genetic damage caused by radiation exposure. Most repetitive sequences are in non-coding regions of the genome and alterations in these loci are usually not deleterious.

Use of mononucleotide repeat markers for detection of microsatellite instability in mouse tumors.

Tumors lacking DNA mismatch repair activity (MMR) from patients with Hereditary Nonpolyposis Colorectal Cancer (HNPCC) or those with sporadic colorectal cancer can be identified by the presence of high levels of instability in repetitive sequences known as microsatellites (MSI). The assessment of MSI phenotype in human tumors helps to establish a clinical diagnosis and is accomplished with a reference panel of five mononucleotide repeats. By contrast, detection of MSI in mouse tumors has proven to be problematic and lack of a uniform set of markers for classification of MSI has impeded comparison of results between studies.