Shibata et al. identified a new form of Extrachromosomal circular DNA (microDNA) in mouse tissues as well as human cell lines. These microDNAs are 200 to 400 bp long. Unlike formerly described Extrachromosomal circular DNA, they are not derived from repetitive sequences, transposable elements, or viral genomes. They are derived from unique nonrepetitive genomic sequences which are often associated with genes. Formation of these microDNA appears to be associated with microdeletions. The generation of microDNAs and microdeletions may be a source of individual-specific or somatic-cloneâ€“specific copy-number variations. Their role in functional differences between cells in a tissue remains to be explored.
Extrachromosomal microDNAs and chromosomal microdeletions in normal tissues. Shibata et al. Science. 2012 Apr 6;336(6077):82-6. Epub 2012 Mar 8. PMID: 22403181
posted by Yannis Trakadis MD, MSc