The 'normal' process is that a cell starts with it's permanent DNA in the nucleus. Part of the DNA [1] is transcribed to a string of RNA, this RNA is translated

The 'normal' process is that a cell starts with it's permanent DNA in the nucleus. Part of the DNA [1] is transcribed to a string of RNA, this RNA is translated to a protein. There is an encoding where the sequence of base pairs along the DNA strand unambiguously specifies the sequence of amino acids that form the protein. The proteins then do the work in the cell (eg. the protocadherins and zinc fingers article mentions). This isn't the only way, and biologists seem to love studying the exceptions, but it is the main pattern found so far. This is the dogma the article refers to: https://en.wikipedia.org/wiki/Central_dogma_of_molecular_biology https://en.wikipedia.org/wiki/Central_dogma_of_molecular_bio... Cephalopods edit their RNA before translation to a protein on a huge scale. Apparently 60% of the RNA sequences in a squid brain study were modified (presumably before translation to a protein) https://phys.org/news/2015-03-squid-enrich-dna-blueprint-prolific.html https://phys.org/news/2015-03-squid-enrich-dna-blueprint-pro... So most of the proteins in that squid brain are not in it's genome (although similar ones are). This is very simplified and I am not a biologist. [1] Roughly speaking each bit of DNA that does this is a gene: https://en.wikipedia.org/wiki/Genes https://en.wikipedia.org/wiki/Genes https://en.wikipedia.org/wiki/Genetic_code https://en.wikipedia.org/wiki/Genetic_code