Polygeny is where one trait is affected by more than one gene. It makes natural selection’s job more difficult by adding considerable noise.
Pleiotropy is where one gene affects more than one trait. This makes natural selection’s job more difficult by adding more noise.
Recessive variations are very difficult for natural selection to work with, adding lots of noise.
Natural selection has a difficult job because some genes depend on others for their effect, adding more noise for natural selection to deal with.
Life’s DNA is a language system; therefore, it could have come only from intelligence.