Dispersed repetitive sequences of the mouse genome are differentially represented in extrachromosomal circular DNAs in vivo.

Eukaryotic cells contain extrachromosomal circular (ecc) DNAs which are homologous to chromosomal sequences. We have isolated eccDNAs from whole tissues of C57BL/6 mice. Using hybridization techniques, we show that R-, MIF-, B1-, and B2-dispersed repetitive sequences of the mouse genome are differentially represented in heart, brain, and liver tissues. Moreover, we show that the relative abundance of B2 sequences in heart and liver eccDNAs is higher than the relative abundance of the other repetitive sequence families studied.