This can give a rather quickly and dirty overview of Dr. Seuss autism be who you are and say what you feel because those who mind don’t matter shirt. the introduction of Mendelian genetics made the modern synthesis, which modelled evolution as a process which begins with a set of genes, which mutate by random deletions and insertions, or occasional duplications, and then the most fit gene fixates in the population independently of other genes. This gene-individualistic model was supported by the observation that crossing over shuffles genes arond, so you can think of the fitness of each gene in isolation to a certain extent, because it will wander about at random through the organisms.
This kind of stuff, the primitive kind of Dr. Seuss autism be who you are and say what you feel because those who mind don’t matter shirt, is not consistent with producing new structures and new tissues of advanced collective genetic function, it doesn’t make any more sense than saying that books are written by a process of copying previous authors, with occasional errors introduced by careless scribes. That’s not how new books are written, they are authored by an intelligent process. This mutation mechanism is required, and it is sufficiently different from the textbook picture of blind mutation that I think it is closer to intelligent design than to the modern synthesis. It is not yet accepted that such a thing is required, because biologists associate complex mutation mechanism with a rejection of the blind, mechanical, idea of the modern synthesis, ideas which were ruled out when they were first proposed, by the absurd time scale in estimates to go from mouse to human by blind mutation.