Thursday, April 09, 2009

So what is DNA and mtDNA all about?

So what is DNA and mtDNA all about?

Gregor Mendel, who was a monk, played a very important role in the discovery of genes and heredity. He is considered to be “the father of genetics” with his famous experiment about peapods that explained the patterns of inheritance.

Over the years, people like Frederick Griffith, Erwin Chargaff, Maurice Wilking, Rosalind Franklin, James Watson, and Francis Crick conducted experiments that offered us a better understanding of DNA in the 20th century. In 1951 James Watson and Francis Crick began to examine the DNA’s structure. Using previous X-ray diffraction photos of DNA fibers taken by Maurice Wilkins and Rosalind Franklin, they discovered that it showed an X shape... which is also the characteristic of a helix. In April of 1953, using this information, they came up with the double helix, the structure that is almost always associated with DNA.

A great deal of information is available on the Internet that explains quite well the history of DNA.

For the purposes of the Acadian Ancestral Home I think it necessary to explain mt DNA as it pertains to the mt DNA Proven Origins of the pioneer Acadian women results posted on this web site.

mtDNA or Mitochondrial is passed from mother to daughter through all of the generations for thousands of years. It does not change and that is why mt DNA testing has become such a useful tool that provides us with information regarding the origins of our first ancestors, especially if those origins were in doubt for lack of records/documentation. For Acadians this is proving to be an important tool. So many documents were lost and or destroyed at the time of the 1755 Diaspora – as a result questions arose as to whether some of the women pioneers of Acadia might not thus have been Native/Métis born of a Mi’kmaq mother and French father.

Can mt DNA pass from father to child?

There are rare occurrences of paternal transfer of mt DNA in humans and other animals. This happens during conception when some mt DNA from the sperm tail mixes with the egg. So far there is only one proven case of this in human mt DNA. Therefore, it is not considered to be a significant contribution to the overall mutation rate of human mt DNA.

In the recent past, some have hypothesized that several Acadian women's maternal lineages were of Métisse [or Native American] descent. Meanwhile, others have hypothesized that the maternal ancestors in question were French women.

When considering alternative hypotheses, it is a sound research practice to seek evidence that would support the correct one. Regarding a number of the women for whom Native American origins were claimed, the advocates of those claims overlooked or covered up the fact that documentation, in the form of the sworn depositions of their descendants at Belle-Île-en-Mer in 1767, existed to show that these women had come from France. In this connection, Stephen A. White, the genealogist at the Centre d'études acadiennes, Université de Moncton, always supported the uncontradicted testimony of the records against any sort of speculation. Whether the conflict be between alternative hypotheses, or between hypotheses and written records, where ancestral lineage is concerned, mt DNA provides the proof all serious researchers have long needed. Thus far, the results obtained through mt DNA testing have demonstrated that nearly all those first Mothers in Acadia about whom there was speculation were of European descent. This has confirmed the reliability of the depositions at Belle-Île-en-Mer to the extent that they speak to the origins of specific ancestors, and the prudence of trusting documentation over conjecture.

Analysis of Native American mt DNAs revealed that most fall into four major haplogroups (A, B, C and D). Each of these haplogroups encompasses a coherent lineage of Native American specific mt DNA haplotypes which trace back to a founding haplotype that is also present in Asia. (Haplogroup X2a has also been found to be Native American.) 1

Analysis of European mt DNA variation has revealed that 99% of European mt DNAs fall into nine haplogroups (H, I, J, K T, R1b, U, V, W, and X). The European mt DNA coalescence time is between 40,000 and 50,000 YBP. (Haplogroup X2b has been found to be European.) 2

The mt DNA Haplogroups 3 - L1, L2, and L3 - found in Sub-Saharan African lineages.

Haplogroups H, I, J, K, T, U*4, V, W and X - found in nearly all lineages from Europe, North African and Western Asian Caucasians.

Haplogroups A, B, C, D, E, F, G and M - found in the majority of the Asian, Oceania and Native American lineages.

Haplogroup M and N are believed to represent the initial migration by modern humans out of Africa. Haplogroup N is the ancestral haplogroup to almost all European haplogroups and many Eurasian.

The mitochondrial haplogroup J contains several sub-lineages. The original haplogroup J originated in the Near East approximately 50,000 years ago. Within Europe, sub-lineages of haplogroup J have distinct and interesting distributions.

Haplogroup J1b is found distributed in the Near East and southern Iberia, and may have been part of the original colonization wave of Neolithic settlers moving around the Mediterranean 6000 years ago or perhaps a lineage of Phoenician traders. Within haplogroup J1b, a derivative lineage haplogroup J1b1 has been found in Britain and another sub-lineage detected in Italy. Further research will better establish the relationship of these two geographically distant, yet evolutionarily related, haplogroups. Bryan Sykes in his Seven Daughters of Eve book named this mt DNA haplogroup Jasmine.

The reason more than one test result for the same ancestor has been posted is because we believe one test alone does not necessarily prove anything. When there is more than one test result is the same haplogroup that adds validity to the findings and it is then a certainty that the results are correct.

To add to the certainty of these results, the lineages were submitted to us previously to being posted here and they were either corrected if that needed to be done, completed if the lineage had not been completed, and verified. What is very interesting is that though the results a similar for those tested to an Maternal Ancestor, they arrived to this Ancestor through various matrilineal lines.

Serious Acadian & French Canadian researchers in the genealogical communities encourage mtDNA testing so that some of the *Unknown* origins of some of our Ancestors can finally come to light. The more people are tested for a particular line, the better.

My thanks to all who have given permission to post their mt DNA Haplogroup results to the Acadian Ancestral Home. No results are posted without the permission of those who have been tested. More results are yet to be posted.

The results provide proof to origins long believed to be what the results are now showing us - that is either European or Amerindian. Some will dispute the findings based on "hearsay" of others that has long circulated without any proof whatsoever. DNA/mt DNA results speak the truth. Both kinds of DNA change at extremely slow rates, so that a change (mutation) that occurred a long time ago (thousands of years) can be traced to today. Each different haplogroup, and each subdivision, represents a mutation that occurred at some time in the past, and that has then been transmitted to descendants to today. So I don't think one should say that it does not change, but that change occurs slowly and that, once a change (mutation) has occurred in some person, it is carried by that person's descendants. We need to come together and encourage others to be tested and support these findings/test results.

*Reference 1: MadSci Network: Genetics

Thank you to George Friedman for his input.

*Reference 2: Origin and Diffusion of mtDNA Haplogroup X

A maximum parsimony tree of 21 complete mitochondrial DNA (mtDNA) sequences belonging to haplogroup X and the survey of the haplogroup-associated polymorphisms in 13,589 mtDNAs from Eurasia and Africa revealed that haplogroup X is subdivided into two major branches, here defined as “X1” and “X2.” The first is restricted to the populations of North and East Africa and the Near East, whereas X2 encompasses all X mtDNAs from Europe, western and Central Asia, Siberia, and the great majority of the Near East, as well as some North African samples. Subhaplogroup X1 diversity indicates an early coalescence time, whereas X2 has apparently undergone a more recent population expansion in Eurasia, most likely around or after the last glacial maximum. It is notable that X2 includes the two complete Native American X sequences that constitute the distinctive X2a clade, a clade that lacks close relatives in the entire Old World, including Siberia. The position of X2a in the phylogenetic tree suggests an early split from the other X2 clades, likely at the very beginning of their expansion and spread from the Near East.

A Description of Haplogroup U6a

This is a very interesting lineage for several reasons. First, I’m positive this lineage is not Native American in origin. The haplogroup U6a is not found in Native American populations, and generally haplogroup U6 is understood to be an African haplogroup. Out of curiosity, I checked our database, which is largely European so understand it is biased to show more European samples than African, for individuals who are in haplogroup U6. Of the people who reported a country of origin it turns out the country of origin with the greatest number of individuals in our database is France.

When someone belongs to a haplogroup that is found in both Native American and non-Native American populations, we often look at the matches to determine which lineage this person is matching. In your case, your group members are an exact match for four out of five of the U6a samples from France. In addition, several of the participants in our database who are U6a, who are an exact match in the HVR1 region, and who did not report a country of origin have distinctly French surnames. While the surname isn’t necessarily descriptive of the origin of the direct maternal line, when I combine this with the fact that France was the country with the most U6a individuals in our database it is very interesting.

From this information, I would conclude that the direct maternal line of your participants is not a Native American line; perhaps there is a European ancestor along that line further than the paper trail is able to trace, or perhaps the Native American ancestor is a male or a different female on that side of the family.

At this point, we still have the interesting question of how did U6a, which research indicates is primarily an African lineage, make it to Europe? Despite U6a’s African origins, I’m certain these lineages came to Canada from France based on the matches. How, then, did they get to France from Africa, where this haplogroup branch is most commonly found?

There are a number of possibilities. U6 may have originated in Europe and this lineage simply did not migrate to Africa. On the other hand, if it originated in Africa, a family could have simply migrated into Europe, but there are also some historical events that would have brought some African lineages into the area. For example, the Moors who invaded Spain left some lineages behind, which could have easily migrated into France. Romans brought African slaves with them and spent a significant amount of time and effort in Gaul. Phoenicians and other traders around the Mediterranean also traded along the coast of Europe; they are known to have traded with Cornwall, so they would easily have traded with France as well. In each of these examples, some lineages would have spread from Africa into Europe (and vice versa).

Finally, U6a is not the most common haplogroup branch. More research will probably shed more light on what population groups it can be found in (both within Africa and outside of Africa) and possibilities for how it migrated and spread to these different areas.

Eileen Krause
Anthrogenealogy Response Center
Family Tree DNA

Oxford Ancestors was founded by Prof Bryan Sykes following press coverage of his genetic research and the publication of his first book “The Seven Daughters of Eve”. Bryan had been using DNA analysis to trace important events in human evolution and to show that everyone on Earth has common ancestry. When this information appeared in the press, he was overwhelmed by requests from the public for personal DNA analysis services.

The DNA that he was using for his research was a specific type called mitochondrial DNA (or mtDNA, for short), which is inherited solely down the maternal line. In other words, your mt DNA is inherited exclusively from your mother, who inherited it from her mother (your grandmother), who inherited it from her mother (your great grandmother), and so on back through time. The analysis of the mtDNA formed the basis of our first service, the MatriLine™ analysis.

The Company was formally incorporated as a University of Oxford “spin-out” in March 2001 and operated, initially, from Littlemore, just south of Oxford. Over the next 12 months, following constant media attention, we were inundated with samples from people who wanted to know more about their own maternal ancestry and their place in the family tree of all humanity. Soon the number of samples became so large that we had to relocate to larger premises, based in Kidlington, just north of Oxford.

Over the last three years, Oxford Ancestors has provided contextualised genetic analysis services that emphasize the connections between us all. We have performed over 10,000 analyzes and helped many thousands of people to discover their ancestral roots.

Migrations Map

If you have been mt DNA tested, the Acadian & French Canadian Ancestral Home would really like make you a part of this important project and would like to post your results the mtDNA Proven Origins page.

If you are of Acadian ancestry and are interested in being tested, the Mothers of Acadia mt DNA Project was approved by Family Tree DNA last year. I am the administrator. If you are of French-Canadian ancestry, I highly recommend that you be tested through the French Heritage DNA/mt DNA Project site that is also part of Family Tree DNA.

Sincere gratitude to Stephen A. White for verifying lineages
submitted by the participants of the Mother of Acadia mtDNA Project and the mtDNA Proven Origins Project.

© Lucie LeBlanc Consentino
Acadian & French Canadian Ancestral Home
2006 - Present

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