Definition

Noun: 1. (Genetics) A type of large cloning vector: A cosmid is a laboratory-constructed DNA molecule, derived from a bacteriophage (a virus that infects bacteria), that is used to clone (make identical copies of) relatively large fragments of foreign DNA, such as genes or gene fragments, inside a bacterial host.

Examples of Usage

• Noun:
  • The researchers inserted the human gene fragment into a cosmid for amplification.
  • This cosmid library contains large segments of the plant's genome.
  • Compared to plasmids, cosmids can carry much larger pieces of DNA.

Advanced Usage

• Cosmid cloning: The process of using a cosmid as a vector to replicate a DNA insert.
  • Cosmid cloning was essential for constructing physical maps of complex genomes.
• Cosmid library: A collection of cloned DNA fragments, each carried within a cosmid vector, which together represent the entire genome of an organism.
  • Scientists screened the cosmid library to find the sequence responsible for the trait.

Variants and Related Words

• Vector (n): In molecular biology, a DNA molecule (such as a plasmid, virus, or cosmid) used as a vehicle to artificially carry foreign genetic material into a host cell.
• Bacteriophage (n): A virus that infects and replicates within bacteria. Cosmids utilize specific sequences (cos sites) from bacteriophages.
• Plasmid (n): A smaller, circular DNA molecule, distinct from a cell's chromosomal DNA, often used as a cloning vector for smaller DNA fragments.

Synonyms

• Cloning vector: A general term for any DNA molecule used to carry foreign DNA into a host cell for replication.

Related Terms and Concepts

• Cos sites: Cohesive end sites; specific DNA sequences from bacteriophage lambda that are present in cosmids and allow the vector DNA to be packaged into phage particles.
• Genomic library: A collection of clones that contains fragments representing the entire genome of an organism; a cosmid library is one type of genomic library.
• Recombinant DNA technology: The set of techniques used to join together DNA molecules from different sources; cosmids are a tool in this field.

Noun

1. (genetics) a large vector that is made from a bacteriophage and used to clone genes or gene fragments