More specifically is how hard is to make mermaids for real?
Google search for
- recombinant animals
- transgenic rodents
Here is the correct way of asking it: how to create a transgenic organism?
That is a good starting point
- https://www.nature.com/scitable/topicpage/recombinant-dna-technology-and-transgenic-animals-34513/
- https://www.nature.com/scitable/topicpage/genetic-mutation-1127/
Then closer to the desired topic
- https://www.nature.com/scitable/topicpage/genetically-modified-organisms-gmos-transgenic-crops-nbsp-732/
- https://www.nature.com/scitable/topicpage/the-use-of-animal-models-in-studying-855/
It is possible to combine several different DNA pieces and then add it two the target organism. Based on paper:
Jackson, D. A., et al. Biochemical method for inserting new genetic information into DNA of simian virus 40: Circular SV40 DNA molecules containing lambda phage genes and the galactose operon of Escherichia coli. Proceedings of the National Academy of Sciences 69, 2904–2909 (1972)
Work with plants
- growing proteins in plants
- vaccine expressed in plants
Though the best bet would be on this book
https://www.sciencedirect.com/referencework/9780080885049/comprehensive-biotechnology#book-info
I'll go to my library