For those that aren't familiar, this principle is known as gene expression: https://en.wikipedia.org/wiki/Gene_expression

To make an analogy to software, a common pattern is to have a monolithic repo with many different "personalities" (codepaths / configurations) that utilize different subsets of the monolith. DNA seems to work under a similar principle, a given cell will preferentially transcribe parts of the DNA based on epigenetic factors.