Not the same reason at all. In genetics the reason is that you're losing gene variety and eventually recessive genes aren't suppressed anymore. In case of LLM it's just error accumulation.
It's a few days late but "losing gene variety" isn't the cause. What happens is genetic errors compound and are more likely to be expressed. I.E. "error accumulation".
How about a number of grad level genetics courses? Does that beat your google search? Because that is what I have. And what I am telling you is what happens.
This is really easily searched (as you said).
You might read up on it if interested. Check out why inbreeding can lead to expression of genetic defects. What is the mechanism? (hint: it's not "losing gene diversity" or "suppression").
`Homozygous, as related to genetics, refers to having inherited the same versions (alleles) of a genomic marker from each biological parent. Thus, an individual who is homozygous for a genomic marker has two identical versions of that marker. By contrast, an individual who is heterozygous for a marker has two different versions of that marker.`
In other words, errors can accumulate and are more likely to be expressed. Not "gene diversity" (this is a topic relating to evolutionary fitness, selection potential etc.), not "suppression". Error accumulation.