Temporal and spatial rearrangements of a repetitive element array on C57BL/6J mouse genome

•The structure of the RE arrayCHR7.32 locus is highly variable depending on tissue types.•The RE arrayCHR7.32 of the skin and brain undergoes temporal rearrangements as mice age.•Rearrangements of RE arrays may contribute to the acquired genome characteristics.•Comprehensive studies examining the role of RE arrays in genome biology are needed.

Repetitive elements (REs) make up the vast majority of the mammalian genomes. We identified species-specific genomic libraries of RE arrays. The non-random configurations of RE arrays suggest their functions. We tested whether RE arrays undergo age- and tissue/cell-specific rearrangements. An RE array of C57BL/6J mice, containing tandem repeats of a mosaic of transposable REs, was selected to examine rearrangements in different ages and tissues. There were marked changes in the array configuration in the genomes of the skin and brain in all mice of six weeks and older, whereas the heart and liver had alterations at 29 weeks. The temporal variations were confirmed by identifying putative rearrangement junctions. Temporal and spatial rearrangements of certain RE arrays may contribute to the acquired characteristics of the genome information system.