Table 1.
Size range of circular DNA in eukaryotes
| Name of circular DNA | Size range | Replication | References | Function (if any) |
|---|---|---|---|---|
| Double-minute chromosomes | 100kb – 3mb | Self | [31, 42–45] | Double minutes contain proto-oncogenes in cancers |
| Extra chromosomal rDNA circle | 19.3 and 40.4 kb | Self | [41, 55] | Accumulation associated with aging, suppress mitochondrial “cheats” in Yeast |
| Telomeric circle | Integral multiples of 738 bp | Self | [22] | Telomeric circles in a wide range of organisms provide telomeric repeat template for restoring telomere length by homologous recombination |
| Mitochondrial circular DNA | 16 kb | Self | [56] | Contains genes essential for mitochondria function |
| Chloroplast circular DNA | 120–160 kb | Self | [57] | Contains genes including essential genes for photosynthesis |
| Alpha satellite circle | 2–20 kb | Self | [22] | Centromere evolution? |
| MicroDNA | 100–1000 bases | ND | [27, 28, 49] | miRNA generation? |
| Kinetoplast maxicircles | 20–40 kb | Self | [58, 59] | Encode ribosomal RNAs and mitochondrial proteins |
| Kinetoplast minicircles | 0.5–1 kb | Self | [58, 59] | Produce guide RNA to decode maxicircle gene information for mitochondria |