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.

The Path From the Old World to the New

The map above shows the theory about how human beings moved from Africa to the rest of the world. The letters refers to mtDNA - the Haplogroups that pass from mother to child.

The five major lineages that make up Native Americans are A, B, C, D, and X. Most scientists believe that America was initially settled from Asia and this is supported by most of the genetic evidence. Most Native Americans are genetically linked to Asia. This fits the long standing theory that the people who populated the two American continents walked across the land bridge that connected Asia with North America during the ice age and later theories that envision boats following the coasts.

The map below shows the distribution of MtDNA lines in America. Lines A through D are the dominant ones and clearly came from Asia. They are distributed throughout North and South America. But X is concentrated in northeast North America. And what is the "other MtDNA" shown for North America?

 americanscientist.org/my_amsci/restricted.aspx?act=pdf&id=2885494546964

The map below illustrates the current location of Male "Y" haplogroups passed from father to son. This is the DNA from the indigenous people - Native Americans and Australian Aboriginals. Note that the America's are populated by descendants of three major groups.

Click to view a larger map.  https://upload.wikimedia.org/wikipedia/commons/c/ca/World_Map_of_Y-DNA_Haplogroups.png

The map below shows the distribution of the male haplogroup "Q", which is inherited from father to son. Most male Native Americans share this haplogroup and it is clear from the map that it spread from north east Asia into America. It appears to be the signature for the first migrants still reflected in current Native Americans. Both continents were settled.

The map below shows the distribution of the male haplogroup "C3".  People with this haplogroup clearly came from Asia and judging from the map, was a later migration into the new world. It did not go further south, probably blocked by earlier migrants to the new world.

Maps are from Wikapedia.

Patterns That Look Like Movements From West Asia or Europe to America

But not so fast. The maps below show patterns that appear more likely to have originated in west Asia and Europe. It is possible that migrants originated in Asia and went by land to America but died out in east Asia and northwest North America, leaving little trace.  This seems unlikely.

The maps above shows the distribution of the male Y Chromosome "R"  Y-DNA, passed from father to son. Most sources contend that this Haplogroup came about in Native Americans recently from post Columbian American colonists. 

Some R-1 no doubt did come from recent European migrants. But the concentration in northeast North America seems too high for all of it to be Post Columbian.  And there is little reason to think that the percentage of R-1 would be so much higher in northeast North America than in other parts of North and South America. 

Wikapedia addresses this issue

A second theory that was introduced during European colonization^[42] can be excluded for the following reasons:^[45]

1. SNP array-based analyses using a data set masked for inferred admixed genomic regions19 gave no matches with recent European admixture.^[45]
2. Allele frequency-based D-statistic tests20 show that all 48 tested modern-day populations with First American ancestry19 are equally related to MA-1 within the resolution of our data, which would not be expected if the signal was driven by recent European admixture.^[45][46]
3. MA-1 is closer to Native Americans than any of the 15 tested European populations.^[45][47]

Central and South America have had longer post Columbian histories of intermarriage than northeast North America but R1 barely shows up there. 

The map above shows the world distribution of haplogroup X, the fifth founding maternal lineage in America. Unlike haplogroups A through D, it is found primarily in West Asia, Europe, and North America. And unlike haplogroups A through D which are distributed throughout North and South Ameria, it is found primarily in northeast North America.  

It was initially thought that persons with this haplogroup were descended from post Columbian European immigrants but now it has been determined that the haplogroup is very old in North America and much different from the X found in Asia and Europe.

The two maps above depict minor DNA lineages in Native Americans that originated in West Asia and Europe and are now primarily in northeast North America.  It is possible that the came from Siberia and then died out in Asia and for some reason did not expand into South America.  But it seems most likely to me that they got to North America by crossing the Atlantic.  

The alternate assumes that they immigrated across Asia and western North America but left little genetic trace of their passage in Asia and northwest North America. And unlike the other Native American groups they are concentrated in northeast North America.

I am certainly not a DNA expert.  But I can read maps. 

Most of the DNA evidence supports immigration from Siberia into the Americas and most Native Americans are descended from these people.

But the male line R1-M173 and the female line X are in my opinion more likely the result of seaborne expansion from west Asia and/or Europe into the new world.

And the two expansions from Asia and Europe/the middle east into America likely occurred at roughly the same time, with the R-M173 and X probably coming into America shortly after the main Native American lineages arrived from northwest Asia. The two peoples would have expanded into their respective territories and then met in the middle, where they blocked further expansion and where over time there has been significant gene exchange. The immigration from Asia continued on to populate central and South America.

Many people believe that the R1-M173 in Native American populations is post Columbian. But it is hard to see that this would have been so strong in northeast North America but not elsewhere.   

Denisova DNA

The graphic above is interesting. It shows the world location of of people with Denisova alleles. Interbreeding with Denisova individuals took place much earlier than movement into the Americas.  

The people of Oceania have the most genetic evidence of interbreeding with Denisovians.  The people of Oceania have the most genetic material from Desinova.

But look at the concentration in the north part of South America. The map looks like a migration by sea from Oceania. The alternative explanation is that the migration came from Siberia over the land bridge but let little trace in North Asia and North America. Rather unlikely.

Anomolous DNA

Click on the link below for an interesting discussion of Anomalous DNA found in Native Americans.

"In the past, whenever a geneticist or anthropologist conducting a study of Native Americans has encountered an anomalous haplogroup, that is, a lineage that does not belong to one of the five generally accepted American Indian mitochondrial DNA haplogroups A, B, C, D and X, it has been rejected as an example of admixture and not included in the survey results. 

Lineage A, B, C, D and X are American Indian.

Therefore, all American Indians are lineage A, B, C, D and X.

The fallacy in such reasoning is apparent. It could be restated as: "All men are two-legged creatures; therefore since the skeleton we dug up has two legs, it is human." It might be a kangaroo."

http://dnaconsultants.com/_blog/DNA_Consultants_Blog/post/Anomalous_Mitochondrial_DNA_Lineages_in_the_Cherokee/

Sioux Indians - R-1 "Y" DNA

The interesting map above shows the Great Sioux Reservation in the American west.  These Native Americans were the classic buffalo hunters, living a nomadic life on the great plains hunting buffalo. They were very successful warriors and of course defeated General Custer at the battle of the Little Bighorn.

As a western tribe their contact with eastern American colonists was minimal in the early years of settlement of the United States.  But their "Y" DNA is about 50% R-1 - higher than some of the eastern tribes such as the Cherokee. This is an argument against the belief that R-1 is the result of post Columbian migration and intermarriage.   


http://www.ndstudies.org/resources/IndianStudies/standingrock/historical_gs_reservation.html

http://en.wikipedia.org/wiki/Y-DNA_haplogroups_in_indigenous_peoples_of_the_Americas

R1b Distribution Problem.

From:  http://www.anthrogenica.com/showthread.php?1308-Another-R1b-distribution-problem  

"Probably everyone here is aware of the R1b distribution problem in northern Europe. It generally gets higher as one approaches the Atlantic, and is highest in Ireland, Britain and the Basques country, so at one time it was assumed that R1b was the Y haplotype for the original Atlantic population. Recent strides in understanding dna changed that thinking, since it is now believed that R1b is only about 4500 years old and likely originated closer to the Black Sea than the Atlantic, so the distribution seems strange unless one assumes massive replacement of Y lineages in the Bronze Age."

"But there's another R1b distribution problem on the other side of the North Atlantic. Surveys of Amerindian Y dna do their best to screen out European dna from the post contact period (an admittedly difficult problem) but some tribes in the high north and in north eastern North America have very high levels of R1b. The reaction of the scientific community so far seems to be

"It must be post contact European dna and the result of a founder affect, so let's not look at the problem too closely." But that doesn't really work, since the R1b levels are highest among the Dene in the high north and among the Algonquin speaking people in north eastern North America, declining as one moves south and west. And R1b is totally absent from the figures for South America, except for one part of Brazil. But South America has had a lot of racial mixing between indigenous people and people from Iberia, where R1b is common, so the attempts to screen out post contact European ancestry must have been successful in South America, except for the more remote parts of Brazil."

"And some of the North American tribes that have high rates of R1b have had later contact and less intermixing with people of European ancestry than other tribes with a lower rate of R1b. For example, the Ojibwe, who live north of the Great Lakes, have 79% R1b (and 25% mitrochondrial X2) and they didn't have much contact with white folks until about 1750. Whereas the Algonquin, who had much earlier contact with Europeans and who intermarried much more with Europeans than the Ojibwe have, show only 38% R1b. And in the far north, some of the Dene tribes who didn't have much contact with white folks until the 19th century show high rates of R1b, with the Chipewyan at 62%, for example. And there isn't much evidence of other "European" Y haplotypes, so one would have to assuming that attempts to screen out European ancestry were largely successful except in the case of R1b."

"It should be fairly easy to find out whether R1b was here before the colonial age by testing old bones. Except that Native North Americans aren't going to let that happen. Another approach would be to look at what subclades are involved in order to see whether it does look like modern European R1b or whether R1b could have evolved independently in North America, from an old strain of R. That seems unlikely, but more likely than any other scenario I could come up with once I decided that the quick explanation of "post contact European ancestry and founder affect" doesn't really work. I'd like to see the issue examined, since the longer science ignores the issue, the longer the Storm Front types and the Edgar Cayce fans have to create their own explanation for why R1b is a common Y among Native North Americans in the high Arctic and in north eastern North America."