What methods are used to create transgenic animals in agriculture?

Transgenic animals in agriculture are created using methods such as microinjection, retroviral vectors, and somatic cell nuclear transfer.

Microinjection is one of the most common methods used to create transgenic animals. In this process, a small amount of DNA is injected directly into the pronucleus of a fertilised egg. The egg is then implanted into a surrogate mother, where it develops into an animal that carries the new gene. However, this method has a low success rate, as only a small percentage of the injected eggs will successfully incorporate the new DNA into their genome.

Retroviral vectors are another method used to create transgenic animals. Retroviruses are a type of virus that can integrate their own genetic material into the DNA of the host cell. Scientists can manipulate these viruses to carry the desired gene, which is then inserted into the genome of the host animal. This method is often used to create transgenic livestock, as it has a higher success rate than microinjection. However, it also has limitations, as the insertion of the new gene is random and can potentially disrupt other genes.

Somatic cell nuclear transfer, also known as cloning, is a more recent method used to create transgenic animals. In this process, the nucleus of a somatic cell, which contains the animal's DNA, is transferred into an egg cell that has had its own nucleus removed. The egg is then stimulated to divide and develop into an animal. This method allows for the creation of an animal that is genetically identical to the donor of the somatic cell. This method is particularly useful for creating transgenic animals with specific traits, as it allows for the selection of cells that have successfully incorporated the new gene.

Each of these methods has its own advantages and disadvantages, and the choice of method often depends on the specific goals of the research or agricultural project. Regardless of the method used, the creation of transgenic animals involves complex biological processes and requires a high level of scientific expertise.