In the case where code is used to convict or acquit someone, I think it should be a well-tested and established program: generally something with the software q

In the case where code is used to convict or acquit someone, I think it should be a well-tested and established program: generally something with the software quality of Linux, or in this case, whatever DNA testing kit is being used by scientists in top-ranking universities. We could also use formal verification based on well-established axioms. For example, maybe we could "prove" that the DNA kit reports accurate results as long as the samples it's given are processed correctly.