Nebullis, with all due regard, you are speculating. What would cause "the other" to mutate, how can we ensure there are no deleterious effects (mutations are generally extremely deleterious), what determines a favorable direction and what target is there for a sequence to hit upon? Do you see how these words "don't get us there" and are, at best, wishful thinking?
[The creation of a new creature is] not speculation at all. Control sequences which modulate the expression of genes were identified long ago. The differential expression of genes accounts for a vast variation in phenotype. As it turns out, (and there was an article discussed on FR, recently), much of the difference between chimp and human brains can be attributed to the differential expression of the same genes.
Well, what does this mean, "the differential expression of genes" and what is the control mechanism? You are again speculating. You surmise that differential gene expression results in differential phenotype, and while it would now seem logical, it is not established.
There are lots of deleterious mutations. The individual organisms that get them die, and don't reproduce. The one rare individual who gets a beneficial mutation survives, reproduces, and passes on that gene. There is no "target" (or at least none that science can observe; as a theistic evolutionist I believe that God planned this all out, but the scientific data can neither confirm or deny that); what fits the environment survives, what doesn't (or does, but is just unlucky) dies. Eventually, natural selection keeps weeding out the mutations that don't work and keeping the ones that do until we get something quite different from what we started with.
Any kind of process which results in an error of replication.
how can we ensure there are no deleterious effects (mutations are generally extremely deleterious),
Since the copied sequence is extraneous, mutations are not likely to be deleterious. The original sequence might not bear the same load of mutations.
... what determines a favorable direction
very little, if anything
and what target is there for a sequence to hit upon?
a fitness selection which is not determined ahead of time.
Do you see how these words "don't get us there" and are, at best, wishful thinking?
No.
Well, what does this mean, "the differential expression of genes" and what is the control mechanism?
The expression of genes is controlled by other molecules, usually proteins which bind to short sequences of DNA up- or down-stream from the protein coding region, and which affect the timing and concentration of protein production. Also, these control elements determine which protein product out of number of possibilities is produced.
You are again speculating. You surmise that differential gene expression results in differential phenotype, and while it would now seem logical, it is not established.
This is elementary material, well established in the literature, available for perusal by anyone with an interest.