[edmccard]

>That some genetic features may be dropped or changed if not required anymore without the pressure of a higher death rate / lower reproduction ... darwinism doesn't seem to explain everything

If the results of a newly-introduced selection pressure can be explained by darwinism / natural selection, then surely so can the results of a removal of selection pressure.

For example, if there are genes that result in lowered fear or agression, and that leads to fewer offspring for wild mice, they will have a lower frequency in a wild mouse population than in a population where they don't lead to fewer offspring. I'm no expert, but it doesn't seem like this particular article requires any additional mechanisms beyond natural selection.