>>8066538Mutations in the DNA can have three affects.
1.) Beneficial
2.) Neutral
3.) Negative
(Some have argued that only beneficial mutations stay, this isn't true. Beneficial or neutral stay within a population, its just that beneficial has a larger likelihood of staying because it is 'selected for' it gives an advantage.)
The question of is evolution a predictive scientifically is nonsense considering our current predictive powers.
As an example take cancer, a micro-evolutionary process in which a single cell will generate genomic instability to generate mutations to allow it to become invasive and successful in new environments.
As an example I'll consider colon polypopsis. A cell must go through several mutations before it can become a late stage adenocarcinoma.
Most simply put, it will be in this order (for a statistically large rate). Loss of APC, Overexpression of KRAS (a driver of cell proliferation), Loss of DCC, Loss of P53.
There are countless other examples of how we can predict the evolutionary pathways cells will take, and thus on a grander scale, larger eukaryotes.
Another example: take an essential gene in bacteria. Modify the expression of this gene so it will only be turned on with in presence of a particularl signal (e.g. a chemical in the nutrient environment.). You do this by changing the promoter not the gene itself (so the promoter here is something that signals when the gene is put on or off). You better believe that when you expose bacteria to this over just a few days, nearly all of them will have evolved to remove the inhibitory effects of the promoter and use the gene as normal. This is evolution, this is easily predictable and the fact that anyone would think otherwise is sad and laughable.
