The issue of genetic algorithms has been addressed, multitudes of times, just because you haven't read all the relevant research does not mean that science has "overlooked" it.

When you say "when scientists determine whether or not a gene lives or dies", what do you mean exactly? The core tenant of evolution is based around genetic mutations, the VAST majority of which are neutral, and build up as junk DNA, but those that are beneficial can have a higher chance at being propagated through a population. Those that are detrimental, have a higher chance at dying out. This is done purely by the mechanics of "natural selection". It seems you have a spurious grasp on the basis of evolution.

To the question of "Why not God?" It's because there is no reason to presuppose a supernatural creator. Why would we? If we can explain a phenomenon by naturalistic means, why would we try and fit in some supernatural being?

Pure methodological naturalism takes on the null hypothesis when it comes to the question, "Does a God exist". We will not suppose one does until sufficient data (I want to emphasize this word..DATA) exists to prove one. You also have to realize that not all claims require the same amount of evidence, extraordinary claims require extraordinary evidence.

You are right, no one ever said that we will know everything, and we will NEVER know everything, but that is not an excuse to shove some God into the places we don't currently have sufficient knowledge (God of the Gaps argument). We simply need to be honest and say, "We don't know." This is what honest scientists (people) do, and we always reserve the right to change our minds if new data is presented. The second you start to assert "truth" without evidence (i.e. DATA) to support your claims, you are being dishonest.

This subject is too big to say, "everyone can choose their own truths", there is a correct answer to this question. Now, just like anything else that we have studied, we need to come to an informed answer based on the current data available, and, like anything else, reserve the right to change our minds if new data becomes available.