CG-rich trinucleotide two-repeats signify novel recombination hotspots conserved across primates and mouse

Abstract We previously reported colonies of GGC and GCC two-repeat units (dyads) across the human genome, which were conserved across great apes. On a genome-wide scale, here we extended our methodology, and mapped the two-repeat units of all combinations of C and G trinucleotides in human, consisting of CCG, CGG, CGC, GGC, GCG, and CGC. The majority of the units coincided in 81,118 colonies (distance between consecutive units < 500 bp). We detected pure units and units that were overlaps of those pure units across the colonies, signifying unequal crossover and recombination at those units. Subsequently, we performed a comparative genomics study of several large and medium-size colonies in other primates and mouse. We found that several of those colonies were conserved, yet with extensive dynamicity, as phylogenetically distant as in mouse. In conclusion, CG-rich two-repeat units signify novel unequal crossover and recombination hotspots of the finest molecular resolution, conserved across primates and mouse.