I heard one fascinating story https://www.nature.com/news/2004/040322/full/news040322-9.html https://www.nature.com/news/2004/040322/full/news040322-9.ht... A

I heard one fascinating story https://www.nature.com/news/2004/040322/full/news040322-9.html https://www.nature.com/news/2004/040322/full/news040322-9.ht... Apparently human big brains evolved after a mutation that left human jaw much weaker than their ancestors. Who can say if we prune unwanted traits, we aren't also pruning some desired traits as well.