![]() ![]() It is ideal to use a fosmid library because of its stability and limitation of one plasmid per cell. The first step in sequencing entire genomes is cloning the genome into manageable units of some 50-200 kilobases in length. A library that provides 20–70-fold redundant coverage of the genome can easily be prepared. įosmids are DNA vectors that use the F-plasmid origin of replication and partitioning mechanisms to allow cloning of large DNA fragments. Conjugation aids in the formation of bacterial clone libraries by ensuring all cells contain the desired fosmid. It later was discovered that the F factor was the first episome and can exist as an independent plasmid making it a very stable vector for cloning. The donor cell maintains a functional copy of the plasmid. On the way into the recipient cell, the corresponding DNA strand is synthesized by the recipient. Conjugation involves using the sex pilus to form a bridge between two bacteria cells the bridge allows the F+ cell to transfer a single-stranded copy of the plasmid so that both cells contain a copy of the plasmid. The fertility plasmid or F-plasmid was discovered by Esther Lederberg and encodes information for the biosynthesis of sex pilus to aid in bacterial conjugation. ![]() Many naturally occurring plasmids contain genes that provide some benefit to the host cell, fulfilling the plasmid’s portion of the symbiotic relationship. Plasmid DNA is segregated to each daughter cell, assuring continued propagation of the plasmid through successive generations of the host cell.
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