http://rbth.com/science_and_tech/2016/02/23/its-official-nat...
According to this research, not only did they find a Siberian link to NAs, but they found a link between Australian indigenous people among some NAs.
Wikipedia says:
Two 2015 autosomal DNA genetic studies confirmed the
Siberian origins of the Natives of the Americas.
However an ancient signal of shared ancestry with the
Natives of Australia and Melanesia was detected among
the Natives of the Amazon region.
The only indication of Africans in South America I can think of are the much later statues and idols of faces from Olmec Mexico, circa 1000 BC, which some claim have "Negroid" features (a supposition that has to be debunked with an unfortunate degree of frequency).
Some people are trying to find more remains, and others are trying to do genetic research on those remains, one theory is that there was two (or more) waves of migration.
Another theory, is that the people that crossed the strait 22000 years ago were negroids, and "co-evolved" to have Asian features like modern Asians because of converging evolution or coincidence.
A third theory that was more popular when there was fewer evidence (when Luzia was first found) was that Luzia features were just normal genetic variation, and that she was a mongoloid that looked negroid because of randomness.
Even more interesting, there are evidence of "negroids" in Brazil at that time, while the "mongoloids" people (the current native americans, that have features shared with asians) timeline seemly match the straight theory, some Brazillian historians believe that what happened is that the first attempt of colonizing South America failed somehow, and when the current natives arrived, they early settlers were already long gone.
As for a controversial archeological dig, one with 40.000 years ago humans in it, see https://en.wikipedia.org/wiki/Pedra_Furada_sites