If Genetics testing finds DNA Mutations, Would it find Spontaneous DNA Mutations? If so, then shouldn’t people be Genetically tested throughout their life?

Question

Say you’ve gone through Radiation treatments, which is known to create DNA mutations, or you’ve smoked for several years also known to create mutations, Wouldn’t a Genetics test pick that up?

In: 5

Answer 1

Mutations only occur in one cell. They may then spread to all of that cell’s descendants, but a bunch of mutant white blood cells or colon lining cells wouldn’t appear in your typical saliva swab DNA test, nor would they be passed down to your offspring.

The tests are also collecting an aggregate from multiple cells, so one mutant in the bunch is unlikely to register compared to the healthy ones.

We do sequence cancer cells specifically sometimes though, as they will have anomalous DNA and are all related.