DNA not in chromosomes.
These are small bits of linear or circular DNA that are part of the human genome but do not live in the chromosomes. They are typically 50,000 to 5 million base pairs in length and do not have centromeres.
Extra-chromosomal DNA (ecDNA for short) was first discovered in boar sperm in 1965. Since then it has been found in all advanced life forms. (And even some not so advanced).
Biologically, ecDNA is associated with many forms of cancer. Oncogenes are probably the best studied aspect of ecDNA.
However it is also associated with gene amplification, regulating RNA expression, sequestering transcription factors, releasing molecules for intercellular communication, controlling immune pathways, and aging.
ecDNA also exists in the normal and aging brain. There are approximately 1 million different kinds of ecDNA in a mouse brain. These are differentiated by brain region, with major anatomical regions having about 20,000 unique sequences each.
ecDNA is not mitochondrial DNA, in mice the mitochondrial DNA only accounts for 11% of the total non-chromosomal DNA.
Here is a detailed discussion of the relationship between ecDNA and cancer.
www.nature.com
Here is a survey of ecDNA in the mouse brain
www.nature.com
These are small bits of linear or circular DNA that are part of the human genome but do not live in the chromosomes. They are typically 50,000 to 5 million base pairs in length and do not have centromeres.
Extra-chromosomal DNA (ecDNA for short) was first discovered in boar sperm in 1965. Since then it has been found in all advanced life forms. (And even some not so advanced).
Biologically, ecDNA is associated with many forms of cancer. Oncogenes are probably the best studied aspect of ecDNA.
However it is also associated with gene amplification, regulating RNA expression, sequestering transcription factors, releasing molecules for intercellular communication, controlling immune pathways, and aging.
ecDNA also exists in the normal and aging brain. There are approximately 1 million different kinds of ecDNA in a mouse brain. These are differentiated by brain region, with major anatomical regions having about 20,000 unique sequences each.
ecDNA is not mitochondrial DNA, in mice the mitochondrial DNA only accounts for 11% of the total non-chromosomal DNA.
Here is a detailed discussion of the relationship between ecDNA and cancer.
Modern biology of extrachromosomal DNA: A decade-long voyage of discovery - Cell Research
Genomic instability is a hallmark of cancer and is a major driving force of tumorigenesis. A key manifestation of genomic instability is the formation of extrachromosomal DNAs (ecDNAs) — acentric, circular DNA molecules ranging from 50 kb to 5 Mb in size, distinct from chromosomes. Ontological...
www.nature.com
Here is a survey of ecDNA in the mouse brain
The extrachromosomal circular DNA atlas of aged and young mouse brains - Scientific Data
Extrachromosomal circular DNA (eccDNA) refers to a distinct class of circular DNA molecules that exist independently from linear chromosomal DNA. Extensive evidence has firmly established the significant involvement of eccDNA in cancer initiation, progression, and evolutionary processes...
www.nature.com
