A concatemer is a long continuous DNA molecule that contains multiple copies of the same DNA sequence linked in series. These

polymer A polymer (; Greek '' poly-'', "many" + ''-mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...

ic molecules are usually copies of an entire

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding g ...

linked end to end and separated by ''cos'' sites (a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

binding

nucleotide sequence A nucleic acid sequence is a succession of bases signified by a series of a set of five different letters that indicate the order of nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. By convention, sequences are usu ...

that occurs once in each copy of the genome). Concatemers are frequently the result of

rolling circle replication Rolling circle replication (RCR) is a process of unidirectional nucleic acid replication that can rapidly synthesize multiple copies of circular molecules of DNA or RNA, such as plasmids, the genomes of bacteriophages, and the circular RNA ...

, and may be seen in the late stage of

bacterial infection Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often beneficial but others can cause infectious diseases. The number ...

phage A bacteriophage (), also known informally as a ''phage'' (), is a duplodnaviria virus that infects and replicates within bacteria and archaea. The term was derived from "bacteria" and the Greek φαγεῖν ('), meaning "to devour". Bacter ...

s. As an example, if the genes in the phage DNA are arranged ABC, then in a concatemer the genes would be ABCABCABCABC and so on (assuming synthesis was initiated between genes C and A). They are further broken by

ribozyme Ribozymes (ribonucleic acid enzymes) are RNA molecules that have the ability to catalyze specific biochemical reactions, including RNA splicing in gene expression, similar to the action of protein enzymes. The 1982 discovery of ribozymes demons ...

s. During active infection, some species of viruses have been shown to replicate their genetic material via the formation of concatemers. In the case of ''

human herpesvirus-6 Human herpesvirus 6 (HHV-6) is the common collective name for '' human betaherpesvirus 6A'' (HHV-6A) and '' human betaherpesvirus 6B'' (HHV-6B). These closely related viruses are two of the nine known herpesviruses that have humans as their prim ...

'', its entire genome is made over and over on a single strand. These long concatemers are subsequently cleaved between the pac-1 and pac-2 regions by

ribozymes Ribozymes (ribonucleic acid enzymes) are RNA molecules that have the ability to catalyze specific biochemical reactions, including RNA splicing in gene expression, similar to the action of protein enzymes. The 1982 discovery of ribozymes demons ...

when the genome is packaged into individual virions.

Bacteriophage T4 Escherichia virus T4 is a species of bacteriophages that infect ''Escherichia coli'' bacteria. It is a double-stranded DNA virus in the subfamily '' Tevenvirinae'' from the family Myoviridae. T4 is capable of undergoing only a lytic lifecycle ...

replicating DNA was labeled with tritiated

thymidine Thymidine (symbol dT or dThd), also known as deoxythymidine, deoxyribosylthymine, or thymine deoxyriboside, is a pyrimidine deoxynucleoside. Deoxythymidine is the DNA nucleoside T, which pairs with deoxyadenosine (A) in double-stranded DNA. ...

and examined by

autoradiograph An autoradiograph is an image on an X-ray film or nuclear emulsion produced by the pattern of decay emissions (e.g., beta particles or gamma rays) from a distribution of a radioactive substance. Alternatively, the autoradiograph is also available ...

y. The observed

DNA replication In molecular biology, DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all living organisms acting as the most essential part for biological inheritanc ...

intermediates included circular and branched circular concatemeric structures that likely arose by

References

Bibliography

* Oxford Dictionary of Biochemistry and Molecular Biology, 2nd ed. R. l., eds. Oxford University Press, 2006. p. 138. Repetitive DNA sequences {{genetics-stub