I will ask you again what is the nearest ancestor ? how can they make such a claim without mapping the genome of this nearest ancestor ?
I will direct you once again to the linked article that addresses your wall of denial / self-imposed ignorance regarding our human ancestry.
Science technology does not currently allow the gene mapping of 4 million year old remains. It's possible that there may never be a method to do so. However, as you are convinced as to a 6,000 year old earth, even if "they" do discover a method of gene mapping such ancient remains, you would be forced to invent even more bizarre conspiracy theories.
With a historical perspectivs, (in the religious extremist case, a hysterical perspective), "they", (scientists), have managed to shine the glaring light of facts and truth into the dark recesses of the creationist mindset promoting fear and ignorance. All of the data presented to you offers rational explanations to what your extremist position insists is magic and supernaturalism.