Polymorphism and Sequence Variations of the HumCD4 Pentameric Microsatellite in an Italian Population Sample

Abstract

A sample of 265 subjects from central Italy was analyzed at the HumCD4 locus by polymerase-chain-reaction (PCR). Phenotypes were identified by comparison with a sequenced ladder, after high-resolution horizontal polyacrylamide gel electrophoresis (PAGE) followed by silver staining. A set of representative alleles was sequenced by Taq-cycle-sequencing with dye terminator labeling and capillary gel electrophoresis strategies. Eight common alleles—5,6,7,8,9,10,11,12—and a rare larger 14, never before described in Caucasians, were found. Allele and genotype frequencies were similar to those described in former studies on Caucasians, with a prevalency of alleles number 5, 6, 10. Sequence analysis showed that the polymorphism is due to a pentameric TTTTC basic motif, tandemly repeated, and that from allele number 10 onwards the fourth repeat presents a T to C translation (CTTTC). Instead, allele number 9 may exist in two forms, because 75% of alleles examined in this study presented the CTTTC motif at the fourth position, while the remaining 25% had the basic repeat structure.

Infrared fluorescent automated detection of thirteen short tandem repeat polymorphisms and one gender-determining system of the CODIS core system

“…Exact identification of the alleles was carried out with ladders constructed with sequenced alleles used in earlier collaborative projects for TH01 [30], vWA [31], FGA [32], …”