[¦sel·fish dē‚äk·sē′rī·bō·nü‚klē·ik ′as·əd] (cell and molecular biology) Any tandemly repeated or dispersed repetitive deoxyribonucleic acid sequence that has no obvious function but can spread and accumulate in the species because of its rapid replication. Also known as junk deoxyribonucleic acid.