Genetic elements capable of horizontal transmission (q.v.). Such HMEs enter host cells during conjugation or infection and subsequently insert their DNAs into the chromosomes of the hosts. In prokaryotes, examples of HMEs are F factors, R (resistance) plasmids, and prophages (all of which see). The transposable elements (q.v.) first identified in corn are examples of eukaryotic HMEs. The Ti plasmid (q.v.) can accomplish transkingdom DNA exchanges. See Chronology, 1977, Lawrence and Oschman; episome, selfish DNA, sympatric speciation.
Subjects: Genetics and Genomics.