Question

How do you make transgenic organisms?

Answer 1

A transgenic, or genetically modified, organism is one that has been altered by recombinant DNA technology, either by combining DNA from different genomes or by inserting foreign DNA into a genome.

Complete answer:
By having a new gene inserted into its DNA, an organism may develop a new trait. The characteristics it exhibits, or its phenotype, may also be changed by modifying the genetic makeup (genotype) of the organism. The new gene can be incorporated into a cell's DNA under suitable conditions;
This gene, along with all the other genes being expressed in the cell, will be transcribed and converted into protein.

Several distinct techniques have been developed. In both of them, the first step includes isolating the gene of interest and then connecting it to another piece of interest.
DNA that contains sequences which allow the gene to be expressed in the recipient organism's appropriate tissues. Using one of the techniques mentioned below, this constructed DNA segment is then injected into the animals.

Microinjection
Eggs are isolated from animals and fertilised in vitro in this process, and then the constructed DNA containing the foreign gene is inserted into the egg's nucleus using a very fine needle. The foreign DNA is injected into the fertilised egg's DNA at random locations. The egg is then inserted in a surrogate animal's oviduct, where the egg then grows. This technique has been used to generate many different types of transgenic organisms, from mice to large animals such as cattles.

Its efficiency in the development of transgenic animals, however is low; only a small percentage of implanted eggs grow into transgenic animals and only a small proportion of these animals express themselves as transgenic animals.
Because of the random injection into the genome of the organism, the inserted gene effectively.

Retroviral Vectors
The gene of interest is introduced into the retrovirus genome and this virus is then used to infect embryonic cells, which then grow into species that bear the gene of interest. This technique, however, is rather inefficient, just like microinjection. The gene is randomly inserted into multiple locations of different embryonic cells in the DNA. Not only could the DNA, as in microinjection, be expressed at low levels or not at all, but it can only be expressed in some cells.

Embryonic Stem Cells transfer
This approach allows the genes of interest to be incorporated into very particular locations in the recipient organism's genome. In tissue culture flasks, embryonic stem cells are isolated from the recipient organism and grown. By injecting DNA containing the gene of interest and sequences that allow the DNA to be inserted into particular locations in the genome, these cells are then updated.

These modified embryonic stem cells are then inserted into the blastocyst stage of a developing recipient organism, and a surrogate mother is implanted with this blastocyst containing the gene of interest. More effectively, the resulting species transmit the gene. Only transgenic mice have been produced using this approach.

Note: It is possible to use GMO practises to produce designer crops that have more nutrients, grow faster and produce more yield, are more pesticide tolerant and use less fertiliser.
GMOs are not always comprehensively checked. A mere 90 days is the shortest GMO testing period, which many fear is simply not enough time to assess all the risks.