>>1129811590% of your statement's have been wrong and you don't really have the background knowledge to make your claims.
When the ancestors of modern Eurasians left africa they were unable to progress too far and were trapped in the border regions for a couple thousand years and assimilated approximately 10$ Neanderthal admixture that was ot directly maladaptive or lethal, it is telling that neither Mitochondrial or Y chromosome lines survive, by doing this they acquired a few useful adaptive mutations from a cold climate adapted hominid relative, this population later split and diverged with one groupd heading into eastern asia where they mixed with another distant hominid species known as the Denisovans, recent research based on computer modelling has identified 3 independent Denisovan sub species admixture events in various parts of asia. mostly in the south
all of this was over 50,000 years ago.
from the same dna analysis they have identified another admixture event this time in sub saharan africa with an as yet unidentified ancient hominid species
