Why alway Neanderthal ancestry - why never Homo Erectus?

Denisovan species is believed to be the yeti from around 13000 years ago (according to a show on science channel this evening). Cross bred with the Sherpas, which helps them live at altitude

en.m.wikipedia.org...

It is curious that all of our supposed ancestors had 48 chromosomes but humans only have 46 with on pair of the 23 fused together. Do we see this type of fusion anywhere else in nature?

What about when they started looking at mitochondrial DNA? What did that tell them? That we have only been in existence for about 200,000 years?

Will we ever regain our true history?

a reply to: ClovenSky
I agree, they took a Homo Erectus, and they altered them.

Do we look like aliens?
No, they look like us.

I wonder why?