Date Published:
JUN 25
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 (2.81 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.
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DOI:
10.1073/pnas.93.13.6470