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A transformation efficiency of 1×10 8 cfu/μg for a small plasmid like pUC19 is roughly equivalent to 1 in 2000 molecules of the plasmid used being introduced into cells. In E. coli , the theoretical limit of transformation efficiency for most commonly used plasmids would be over 1×10 11 cfu/μg.
pBR322 is a plasmid and was one of the first widely used E. coli cloning vectors. Created in 1977 in the laboratory of Herbert Boyer at the University of California, San Francisco, it was named after Francisco Bolivar Zapata, the postdoctoral researcher and Raymond L. Rodriguez. The p stands for "plasmid," and BR for "Bolivar" and "Rodriguez."
Minicircles are small (~4kb) circular plasmid derivatives that have been freed from all prokaryotic vector parts. They have been applied as transgene carriers for the genetic modification of mammalian cells, with the advantage that, since they contain no bacterial DNA sequences, they are less likely to be perceived as foreign and destroyed.
They are the standard cloning vectors and the ones most commonly used. Most general plasmids may be used to clone DNA inserts of up to 15 kb in size. One of the earliest commonly used cloning vectors is the pBR322 plasmid. Other cloning vectors include the pUC series of plasmids, and a large number of different cloning plasmid vectors are ...
For example, pBR322 is a medium copy number plasmid (~20 copies/cell) from which several high copy number cloning vectors (>100 copies/cell) have been derived by mutagenesis, such as the well known pUC series. [1] This delivers the convenience of high plasmid DNA yields but the additional burden of the high copy number restricts the plasmid size.
The bacterial artificial chromosome's usual insert size is 150–350 kbp. [4] A similar cloning vector called a PAC has also been produced from the DNA of P1 bacteriophage. BACs were often used to sequence the genomes of organisms in genome projects , for example the Human Genome Project , though they have been replaced by more modern technologies.
A restriction map is a map of known restriction sites within a sequence of DNA.Restriction mapping requires the use of restriction enzymes.In molecular biology, restriction maps are used as a reference to engineer plasmids or other relatively short pieces of DNA, and sometimes for longer genomic DNA.
P1 vectors also contain a P1 plasmid replicon, which ensures only one copy of the vector is present in a cell. However, there is a second P1 replicon- called the P1 lytic replicon- that is controlled by an inducible promoter. This promoter allows the amplification of more than one copy of the vector per cell prior to DNA extraction. [2] bac vector