What is a counter selectable marker?

Negative or counterselectable markers are selectable markers that eliminate or inhibit growth of the host organism upon selection. An example would be thymidine kinase, which makes the host sensitive to ganciclovir selection.

What are selectable markers 12 examples?

Selectable markers are the genes present in the cloning vectors that help in eliminating the non-transformants. E.g. antibiotics resistance genes, herbicide resistance genes, etc.

What is selectable marker role?

A selectable marker enables selection of the transformed cells. Generally, these markers impart resistance to phototoxic compounds like antibiotics and herbicides. It is a stable dominant gene and is integral part of transformation vector.

What is a counter selection?

Counterselection is a genetic engineering technique to eliminate specific genetic fragments containing selectable marker genes. Although the technique is widely used in bacterial genome engineering and plasmid curing experiments, the repertoire of the markers usable in Escherichia coli is limited.

What is insertional activation?

Definition. Insertional activation/inactivation refers to either activation of an endogenous gene which is located near an integrated transgene, or to disruption of a gene or other functional sequence by insertion of a transposable element.

What does the T refers in T DNA part of Ti plasmid?

The transfer DNA (abbreviated T-DNA) is the transferred DNA of the tumor-inducing (Ti) plasmid of some species of bacteria such as Agrobacterium tumefaciens and Agrobacterium rhizogenes(actually an Ri plasmid). The T-DNA is transferred from bacterium into the host plant’s nuclear DNA genome.

When lac Z is used as a selectable marker?

When the recombinant DNA is inserted into the lac z gene, which codes for the enzyme -galactosidase, it gets inactivated and the recombinant colonies do not produce any colour in the presence of chromogenic substrate so they act as a selectable marker. Non-recombinant colonies produce blue colour colonies.

What is the use of Ti plasmid in biotechnology?

The role of Ti plasmid in biotechnology is that it may be converted into a cloning vector by deleting the pathogenicity genes. The Ti plasmid delivers a DNA fragment into normal plant cells, causing them to convert into tumour cells.

What are selectable markers in pBR322?

pBR322 contains two selectable markers, i.e. antibiotic resistance genes for ampicillin (ampR) and tetracycline (tetR). Further reading: Plasmid.

How is Ti plasmid used in Rdna?

The Ti plasmid vector. In plant genetic engineering, the Ti plasmid can be used to carry foreign genes into plant cells. The Ti plasmid is the disease-causing agent of the soil-borne bacteria Agrobacterium tumefaciens.