Mutation and propagation
Genetic change can be brought about by using wild type organisms with their default DNA and inducing mutation e.g. through physiochemical routes like exposure to UV radiation or mutagenic chemicals; selective breeding to bring out recessive characteristics or emphasise particular traits; and culture of recombinant DNA that introduces artificial elements to the existing DNA, e.g. new sequences taken from a different species, an inhibitory sequence that switches off an existing function, etc.
Bacterial species can readily exchange DNA between them, as well as assimilate it from their environment. Fungi can undergo sexual reproduction to produce offspring with potentially new genotypes and phenotypes.
Culturing newly made or found mutants isn’t necessarily easy, due to their genetic instability. If introduced to a continuous culture, they may revert back to their wild type.
Say we are interested in the gene for insulin. Sure, we could take it straight from people, but remember humans are eukaryotes and eukaryotes have non-coding sequences within their genes called introns. The mRNA following splicing, on the other hand, has no introns! How can we make DNA from…