Biotechnology Archive
Severe combined immunodeficiency (SCID) occurs when both the B cells and T cells of the immune system are defective and results in an almost totally defective immune response. Children with SCID have to be shielded from all contact with other …
Retroviruses infect many types of cells in mammals. They need dividing cells for successful infection, and will not infect many tissues where host cell growth and division have come to a standstill. Moreover, the genetic material of retroviruses passes through …
About one in 2000 white children suffer from cystic fibrosis . This condition is due to homozygous recessive mutations. In other words two defective copies of the gene, one from each parent, must be inherited for the child to suffer …
Adenoviruses are relatively simple, double-stranded DNA viruses that infect humans and other vertebrates. The virus particle consists of a simple icosahedral shell, or capsid, containing a single linear dsDNA molecule of approximately 36,000 base pairs. A terminal protein protects each end …
The original idea behind gene therapy was curing hereditary defects by replacing defective genes. However, there is no inherent reason why gene therapy must only be “defensive” and suppress defects. We can go on the offensive and provide genes whose …
During replacement gene therapy, we normally think of replacing the whole defective gene with a complete functional copy. However, some genetic defects consist of just a single base change, or perhaps a cluster of closely linked base alterations. In this …
Genetic engineering means that we alter an organism permanently so that the changes will be stably inherited. For multicellular organisms this implies deliberate alteration of the DNA in the germline cells. In contrast, gene therapy (occasionally called genetic surgery ) …
The polymerase chain reaction (PCR) amplifies small samples of DNA into large amounts, much as a photocopier makes many copies of one sheet of paper. The DNA is amplified using the principles of replication, that is, the DNA is replicated …
Once the gene of interest is cloned into a vector, the construct can be put back into a bacterial cell through a process called transformation. Here the “naked” DNA that was constructed in the laboratory is mixed with competent E. …
Cloning vectors are specialized plasmids (or other genetic elements) that will hold any piece of foreign DNA for further study or manipulation. The numbers and types of plasmids available for cloning have grown. In addition, other DNA elements are now …