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Description:
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Microsatellites are highly mutable , repetitive sequences commonly used as genetic markers , but they have never been assayed en masse . Using a custom microarray to measure hybridization intensities of every possible repetitive nucleotide motif from 1 -mers to 6 -mers , we examined 25 genomes . Here we show that global microsatellite content , as measured by array hybridization signal intensities , independently validates data from published sequence databases and is a sensitive and specific gauge of mutation in an in vitro model of microsatellite instability , an MLH1 knockout (RKO6 ) cell line . Moreover , we demonstrate that microsatellite content varies predictably by species , and that particular motifs are characteristic of one species versus another . For instance , hominid -specific microsatellite motifs were identified despite alignment of the human reference , Celera , and Venter genomic sequences indicating substantial variation (30 -50 % ) among individuals . Differential microsatellite motifs were mainly associated with genes involved in developmental processes , while those found in intergenic regions exhibited no discernible pattern related to transcription factor binding sites or non -microsatellite repetitive sequences (i .e . , LINEs , and SINEs ) . This is the first description of a method for evaluating microsatellite content to classify individual genomes . |