![]() Transformation frequency is increased with the use of cosmids.įigure 2: A Cosmid Similarities Between Plasmid and Cosmid.Genetic linkage studies can be carried out easily.Gene libraries with small clone members can be expanded into the whole genome with cosmids.Since cosmid vectors are capable of inserting large DNA fragments when compared to plasmids, they are suitable for cloning large mammalian genes or multi-gene fragments. Additionally, cosmids can accommodate up to 45 kb sized fragments. Both plasmids and cosmids share the origin of replication, a marker gene, which codes for antibiotic resistance, and a special site for the insertion of a foreign DNA piece. Therefore, the formation of viral particles is prohibited in cosmids. But, cosmids do not have genes that encode viral proteins. The presence of the cohesive end site, cos λ in a plasmid allows the plasmid to be packaged in vivo into viral particles. They contain cos genes of the λ bacteriophage. Plasmids do not freely occur in nature.Ĭosmids are hybrid vectors derived from plasmids.Plasmids can be sequentially reintroduced into new cells and the transformants can be selected.The insertion of a foreign DNA piece may not alter its replication properties.Plasmids consist of a unique restriction site for one or more restriction enzymes.Plasmids are capable of self-replicating inside a cell.Plasmids can be readily isolated from cells.Plasmids are types of vectors which are used as vehicles to carry genetic information to a second cell. Naturally occurring plasmids can be modified by in vitro techniques such as code transformation. They contain the necessary information for antibiotic resistance, metal resistance, nitrogen fixation, and toxin production. However, plasmids are not necessary for the survival of bacteria under normal conditions. ![]() ![]() Plasmids are extra-chromosomal, self-replicating, double-stranded, circular DNA molecules, usually found in bacterial cells. Key Terms: Vector, Plasmid, Cosmid, Hybrid Vectors, Double-stranded DNA, Bacteria, Cos site, Insert What is a Plasmid What is the difference between Plasmid and Cosmid ![]() What are the similarities between Plasmid and CosmidĤ. The main difference between plasmid and cosmid is that plasmid is a loop of double-stranded DNA, naturally found in the bacterial cytoplasm and replicates independently from chromosomes whereas cosmid is a type of plasmid constructed by the insertion of cos sequences from the λ phage. They are widely used in the laboratory manipulation of genes. Vectors are self-replicative, double-stranded DNA molecules. Viral vectors and artificial chromosomes are the other types of vectors that carry foreign DNA. Plasmid and cosmid are two of the four types of vectors that artificially carry foreign genetic material into a second cell. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |