Niskokopijski

Niskokopijski is a term used in genetics, often in Slavic-language literature, to describe genetic elements that exist in a low copy number within a cell. It is typically applied to plasmids and certain DNA sequences that are present only in a few copies per genome, in contrast to high-copy-number elements that are numerous within the same cell. The exact copy number can vary by host strain, growth conditions, and the origin of replication.

In bacterial systems, low-copy plasmids generally maintain between roughly one and a handful of copies per chromosome rather than tens or hundreds. Copy number is primarily determined by the origin of replication and any plasmid-encoded regulatory mechanisms. Low-copy plasmids tend to impose a smaller metabolic burden on the host and can provide more stable inheritance across generations, at the expense of lower production yields compared with high-copy plasmids. They are often preferred when precise gene dosage, tight regulation, or reduced recombination risk is important for a given experiment.

Measuring copy number typically involves quantitative methods such as qPCR or digital PCR, often compared to a single-copy chromosomal gene or marker. In practice, researchers select niskokopijski plasmids or DNA elements to balance stability, expression level, and cellular burden. The concept also extends to chromosomal regions that exist in multiple, but limited, copy numbers under certain cellular conditions.