Comparative Analysis of TG/CA Repeats in Sixteen Primate Genomes Reveals the Dynamics and Role of TG/CA Repeats in the Human Genome

Among the different microsatellite sequences found in the human genome, the dinucleotide TG/CA repeats are one of the most abundant, exhibiting multifaceted functional roles. Availability of several primate genomes offers relevant datasets for studying the evolution and function of these repeats in non-human primates and human genome. Using pairwise genomic alignments, genome-wide analysis of these repeats was performed in human and sixteen other primate genomes. The total number of these repeats and expansion of medium (12≤ n< 23) and long (n≥23) (TG/CA) n repeats was significantly higher in human than other primates. Further, other dinucleotide repeats like TA were found in the orthologous genomic regions in other primates. Thus, selection, elongation and a selective process of conversion of other dinucleotide repeats in primates to TG/CA repeats in humans was apparent and presented in this study as a comprehensive model for the dynamics and role of TG/CA repeats in the human genome.