Extrachromosomal DNA

Three papers in Nature have reported how extrachromosomal DNA (ecDNA) contributes to the progression of cancer and drug resistance.

---

Key Facts 

• Extrachromosomal DNAs (ecDNAs) are DNA molecules found outside the chromosomes in cells. 
• Unlike chromosomal DNA, which is located in the nucleus of eukaryotic cells or the nucleoid region in prokaryotes, ecDNAs exist independently in the cell.

• In some cells, particularly cancer cells, ecDNAs are circular DNA molecules that carry multiple copies of certain genes. These genes can contribute to things like drug resistance by amplifying specific traits.
• Chromosomal DNA contains the complete genetic instructions needed for an organism’s development, function, and reproduction. 
• It contains the majority of genetic instructions necessary for the development, functioning, and reproduction of an organism.
• In humans, the genetic blueprint is contained in 23 pairs of chromosomes, each made up of a long strand of DNA.