[spfzero]

I don't know if I would call this an evolutionary response. It's more like the remnant effect of the one-time bottleneck the article mentions. The proportion of females with the gene for tusks was almost wiped out, while the number of females without that gene stayed the same.

There have only been a few generations gone by since then, but you would imagine the same factors that made the gene for tusks more successful in the first place, would start to again predominate, but it will probably take many generations for it to come back to where it was. That part, the recovery, could be called an evolutionary response.