If your model made any sense, then there would be a gradual progression towards increased genetic abnormalities, to such an extent that from the gene pool of Adam and Eve, to the current generation, barely anyone born today could have escaped drastic genetic defects. This, however, isn’t the case, thus implying that no “perfect” genetic source originally existed to be corrupted later on, least of all, out of a gene-pool of two members, propagating their generations, to the multi-billions, by incest.
Not only that but every indication of human excellence is increasing on average as more and more of the world gets access to better nutrition, modern medicine, and athletic enhancements.
The human population has never been so tall, well nourished, intelligent and healthy.
Moreover according to the model of only accumulating genetic defects. White skin is a defect of the system that would cause dark skin and thus would be more ‘polluted with genetic faults’, at least in the genes for skin color. Amazing to me that Creationists tend to avoid this obvious implication of their ‘model system’.