multicopy

Multicopy is a term used to describe something existing in multiple copies. In biology, it often refers to sequences or genes present more than once in a genome.

In genomes, multicopy sequences may be identical or diverge (paralogs). Examples include ribosomal RNA gene clusters, tRNA genes, histone gene clusters, and abundant repetitive elements such as LINE-1 elements and SINEs. Variation in copy number among individuals, called copy number variation (CNV), contributes to phenotypic diversity and disease risk. Mechanisms generating multicopy sequences include gene duplication, unequal crossing over during meiosis, replication slippage, and transposition.

In molecular biology, multicopy plasmids replicate to multiple copies per cell, depending on the origin of replication and host. High-copy plasmids yield many copies per cell and are commonly used for rapid DNA production; they can burden the host cell and reduce genetic stability. Low-copy plasmids are more stable but provide lower DNA yield.

In information technology, multicopy can describe data replicated across multiple storage devices or sites to increase availability and fault tolerance. Related concepts include replication, mirroring, and multi-site backups; the term multicopy is less common but conveys the idea of redundancy.