The Mystery of mtDNA X2

People arrived in America from Siberia via Beringa, the submerged land between Alaska and Siberia.  The current occupants of North and South America have clear genetic links to Asia.  One of the pieces of evidence is the mtDNA, which passes from mother to child with few modifications.  Native Americans have five major varieties of mtDNA, labelled A, B, C, D and X.

A through D are clearly from Siberia and there is little disagreement there. Most current Native Americans share these mtDNA's  They are found throughout North and South America. But X is a little different.  As shown on the map below, it originated in west Asia, and somehow got to America, where it is concentrated in the northeast part of North Ameria. It has left no remaining X2a people in its path.  The X2 shown on the map is sister Mtdna's to X2a, not other remnants. 

The map above shows the world wide distribution of MtDNA X.  It originated in the middle east, and mutated and expanded from there into Europe, western Asia, north Africa, and eastern North America. It slowly mutated and the sister classes can be followed.

The X2a shown in North America is unique to North America, and to date has not been found in the old world. Europe, Asia, and Africa are sister clades - not ancestral to the X2a in America. 

There are two likely ways that the women with X2a reached America shown on the map, either by:

A.  Traveling east across Asia, Siberia, Alaska, and leaving little trace of their path. This is what most experts believe happened. Or alternately came the same way, by boats.

B. Traveling across the Atlantic, with is what the adherants to the 

Solutrean hypothesis

 believe. They think that some people migrated from southwestern Europe, noting the similarties of the Solutrean culture in Europe and Clovis and pre Clovis in America. But there is also no trace of X2 in this case either.

https://ore.exeter.ac.uk/repository/bitstream/handle/10871/17123/SH%20Mammoth%20in%20the%20Room%20FINAL%20with%20figures.pdf

I am not competent to judge the genetics and leave that to the experts.  I am knowledgeable about military campaigns, which in effect is what happened in the settlement of America.

Comments

Either path is possible. But the origin of X2a in America is in the northeast corner of North America, and spreads west and south from there. It does look like it got their via boat.

If it came from Siberia with the other MtDNA's you would expect it to spread through out the Americas.  With its concentration in northeast North America, and eastern entrance looks more plausible. 

We will eventually know the truth.  Our scientists are getting better at finding DNA from ancient skeletons.

We should also learn more after more research on R1 M-173 - How closely is it related to other concentrations of R in other parts of the world - where in the world is its closest relative concentrated and how many years has it been separate?

Science is making rapid process in learning more about DNA.  I would think we will know within a few years which theory is correct.