Linkers or spacers are short amino acid sequences created in nature to separate multiple domains in a single protein. Most of them are rigid and function to prohibit unwanted interactions between the discrete domains.

Recombination linkers are short segments of DNA that promote recombinational joining of unrelated DNA fragments (Raymond et al. The strength of the approach is that the linker sequences are used to target recombinational cloning to specific sites in the target BAC.

The key difference between linker and adaptor is that a linker does not have cohesive ends while an adaptor has one cohesive end. DNA ligation is the process of joining two DNA molecules together, forming phosphodiester bonds. Adaptor has one sticky end and one blunt end, while linker has two blunt ends.

Linkers are used for various cloning strategies to introduce restriction sites in the DNA after ligation. Linkers are short synthetic palindromic sequences that self-anneal to form blunt ended double stranded fragments.

Linkers are words that relate one idea or sentence of the text with another. They connect the ideas logically. Why are they used? They give direction to the writer. They are also used to guide the reader through his thoughts.

An adapter or adaptor, or a linker in genetic engineering is a short, chemically synthesized, single-stranded or double-stranded oligonucleotide that can be ligated to the ends of other DNA or RNA molecules. It may be used to add sticky ends to cDNA allowing it to be ligated into the plasmid much more efficiently.

Abstract. The adaptor polymerase chain reaction (PCR) permits the amplification of DNA fragments with arbitrary sequences. In this paper, we describe the successful amplification of plasmid-derived single molecule DNAs digested by a restriction enzyme.

The vector pBR322 was named according to the standard rules for vector nomenclature. The “p” stands for plasmid. “BR” tells us which laboratory the vector was constructed in. This part of the vector name stands for Bolivar and Rodriguez, two of the scientists who constructed the pBR322 cloning vector in 1977.

pBR322 DNA is a commonly used plasmid cloning vector in E. coli (1). The molecule is a double-stranded circle 4,361* base pairs in length (2). pBR322 contains the genes for resistance to ampicillin and tetracycline, and can be amplified with chloramphenicol.

Rop (also known as repressor of primer) is a small protein responsible for keeping the copy number of ColE1 and related bacterial plasmids low in E. Due to its small size and known structure, Rop has been used in protein design work to rearrange its helical topology and reengineer its loop regions.

pSC101

A selectable marker is a gene inserted into a cell, in particular a bacterium or a cultured cell, which confers a trait appropriate for artificial selection. Complete answer: Genetic engineering is a process by which recombinant DNA technology is used to change the genetic makeup of the organism.

Selectable markers are the sites present in the vectors plasmid, used to distinguish between tranformant and non transformant cell. E.g. Antibiotic resistance gene like BaH MI-provides tetracycline resistance. Chromogenic genes.

Hint: The selectable markers are the gene substances that are injected in the cell so that it can offer resistance to the action of the antibiotics. This helps in the maintenance of the plasmid in the cell. Due to this selective marker, the plasmid serves very useful to the cell by making it survive.

• it must be small in size.
• It must be self-replicating inside host cell.
• It must possess restriction site for Restriction Endonuclease enzymes.
• Introduction of donor DNA fragment must not interfere with replication property of the vector.

A good vector must have the following properties : (a) It should be able to replicate autonomously. It should have an Origin of replication. (b) It should have selectable markers so that it can be easily isolated .

Properties of an ideal vector

• It should be replicate autonomously.
• A vector should be less than 10 KB in size.
• It should be easily isolated and purify.
• It should be easily introduced into the host cell.
• It should have suitable marker genes.