i'm just trying to pull the old memories from reading my 3 grow guides, particularly the '85 or so edition of indoor MJ horticulture about on a monthly basis even if i had no beans or genes. i KNEW kees at SSSC was full of BS when he tried to assure me skunk #1 was "just what i'm looking for".
i like the great diversity out there. that makes for a healthy gene pool. if you restrict a gene pool too much, especially with inbreeding, you lose breeding vigor. definitely read the revised edition of indoor hort. it should contain most of what any grower should need to know and even dabbles in college level genetic theory. i just skimmed those chapters for the gist.
genetic mutations happen naturally. the longer you try to extend a given set of genes through cloning, the more mutations will creep in. like i said, i'm pretty sure it's called genetic waning. that's why when breeders seek to refresh a tired old strain, they use strains with very different traits to get hybrid vigor instead of "in breeding" with strains that have traits closer to what's desired in the original.
the worst route to cuttings getting tired is making copies of copies as i recall. it's best to keep your clone mother as long as possible, but even she gets old eventually.