Outside of, or separated from, a chromosome. ... (05 Mar 2000) ... 
(eks″trә-kro″mo-so´mәl) outside or not involving the chromosome; as in mitochondrial inheritance, which involves only mitochondrial DNA.
Type: Term Pronunciation: eks′tră-krō′mō-sōm′ăl Definitions: 1. Outside or separated from, a chromosome; especially DNA separated from a chromosome.
of or pertaining to DNA that exists outside the main chromosome and acts independently.