is_proper_part_of extrachromosomal replicon novel extrachromosomal replicon An extrachromosomal replicon that is variant in a genome in virtue of its being a novel addition to the genome - i.e. it is not present in the reference for the genome in which it is found. aberrant extrachromosomal replicon Extrachromosomal replicons are replicated and passed on to descendents, and thus part of the heritable genome of a cell or organism. In cases where the presence of such a replicon is exogenous or aberrant (i.e. not included in the reference for that genome), the replicon is considered a 'sequence alteration'. exogenous extrachromosomal replicon transgenic extrachromosomal replicon novel replicon chromosome