extrachromosomal
ex tra chro mo so mal |ˌekstrəˌkrōməˈsōməl ˌɛkstrəˌkroʊməˈsoʊməl | ▶adjective Biology situated or operating outside the chromosome: extrachromosomal DNA.
extrachromosomal element
extra |chro ¦mo ¦som ¦al elem |ent ▶noun Genetics the DNA of a cytoplasmic organelle, such as a mitochondrion or chloroplast, responsible for cytoplasmic inheritance.