title: Microsatellite spreading in the human genome: evolutionary mechanisms and structural implications.
abstract: Microsatellites are tandem repeat sequences abundant in the genomes of higher eukaryotes and hitherto considered as "junk DNA." Analysis of a human genome representative data base (2.84 Mb) reveals a distinct juxtaposition of A-rich microsatellites and retroposons and suggests their coevolution. The analysis implies that most microsatellites were generated by a 3'-extension of retrotranscripts, similar to mRNA polyadenylylation, and that they serve in turn as "retroposition navigators," directing the retroposons via homology-driven integration into defined sites. Thus, they became instrumental in the preservation and extension of primordial genomic patterns. A role is assigned to these reiterating A-rich loci in the higher-order organization of the chromatin. The disease-associated triplet repeats are mostly found in coding regions and do not show an association with retroposons, constituting a unique set within the family of microsatellite sequences.
authors.affiliation: Department of Molecular Genetics, Hebrew University, Hadassah Medical School, Jerusalem, Israel.
authors.forename: E
authors.initials: E
authors.lastname: Nadir
authors.forename: H
authors.initials: H
authors.lastname: Margalit
authors.forename: T
authors.initials: T
authors.lastname: Gallily
authors.forename: S A
authors.initials: SA
authors.lastname: Ben-Sasson
mesh_terms: D005075:Biological Evolution; D004276:DNA, Satellite; D006801:Humans; D018895:Microsatellite Repeats; D018626:Retroelements; D012689:Sequence Homology, Nucleic Acid
chemical_list: D004276:DNA, Satellite; D018626:Retroelements