Now that things have calmed down a bit from the whirlwind of the Family Tree DNA Conference, I’d like to write in a little more comprehensive and sane manner about the revelation that we have a new root on the human tree.
I’m referring to the session given by Bonnie Schrack, Thomas Krahn and Michael Hammer titled “In Search of the Root: Discovery of a Highly Divergent Y Chromosome Lineage.”
Bonnie has posted her slides from the presentation as well as her speaking notes on her new haplogroup A webpage. She contacted me with some corrections to my original Blog posting about that session at the conference as well as provided additional information. Thank you Bonnie, not just for this info, but for your work with haplogroup A that has been such a key part of this momentous discovery. This isn’t just a once-in-a-lifetime event, it’s a once-in-the-history-of-mankind event. Watch the haplogroup A website for more information from Bonnie about this exciting discovery and project.
Understandably, Bonnie, Thomas and Michael are somewhat restricted in what they can say until such time as the resulting academic paper in the works is published.
We all know that male humans arise from a person we call Y-line Adam, just like we call the first woman Mitochondrial Eve. Before a 2011 paper, it was believed that shortly after Adam, haplogroup A and B were formed about the same time and were brother haplogroups. Fulvio Cruciani’s 2011 paper, “A Revised Root for the Human Y Chromosomal Phylogenetic Tree: The Origin of Patrilineal Diversity in Africa” reorganized that tree and showed that indeed, haplogroup A formed from the root of all humanity with B forming from haplogroup A.
Cruciani showed his newly organized tree with haplogroup A1b, A1a and then A2, A3 and BT as brother haplogroups. Cruciani did not use STR data, only SNP data in his study.
A second recent study, also in 2011, “Signatures of the pre-agricultural peopling processes in sub-Saharan Africa as revealed by the phylogeography of early Y chromosome lineages” by Chiara Batini et al, did include some STR marker that matched some of the haplogroup A samples. Batini did not use SNP testing, so did not realize the potential of these STR samples. These did not match the new A00 root, but other rare haplogroup A samples in subgroups.
The 7 marker STR samples that did match the new A00 sample were from a private database at the Center for Genetic Anthropology who very graciously worked with Michael Hammer and provided small amounts of those samples for further analysis.
In my conference blog posting, I asked how this discovery was previously missed, and Bonnie Schrack responded as follows:
“The reasons we had never heard about A00 before would be:
- Very scanty research and sample collection in Africa, in proportion to the size and diversity of the population, compared to Europe and other more developed countries
- Only recently has large-scale Y sequencing become practical and affordable; Cruciani’s 2011 paper was a breakthrough precisely because for the first time they were able to sequence a few samples on the scale of a WTY, resulting in a lot of new SNPs, and we’ve been able to make even more progress because we had a larger pool of (customer) samples from which I could cherry-pick the most divergent samples, and then our genetic genealogy/anthropology community made it possible to raise enough funds for us to sequence the most important three of them (after that point, Hammer and FTDNA found the other samples and funds).”
Before the WTY program, this type of analysis simply wasn’t being done. This monumental discovery was a combination of citizen science, the haplogroup A project, an innovative scientific program, the WTY at Family Tree DNA, academic partnership, Michael Hammer’s lab at the University of Arizona and other institutions, along with that crucial public participation. Without the public participation aspect, the rest would be a moot point.
Haplogroup A research at Family Tree DNA discovered not only one, but two new branches of haplogroup A, one of which was actually a new base root that needed to be inserted before, upstream of, the current root. The locations where these new branches/roots needed to be inserted required the renaming of the current branches, hence, the newly discovered branch A00 and Cruciani’s branch, formerly A1b, is now A0.
Thomas Krahn’s A00 discovery presentation slides are also available online. You can tell he’s a scientist from the nature of his presentation. You can see the actual process of discovery, in essence, what he saw as this new root was unearthed. It’s fun to walk along with him, even if you don’t understand everything you see.
As part of this process, Thomas also sequenced the DNA of a chimp and a gorilla. You can see the results at www.ysearch.org for the chimp at 6RCUU, the gorilla at 9ED3A and the new root, A00, at 6M5JA. You can breathe easy, humans are far distant from chimps and gorillas, but maybe closer to Neanderthals or other archaic humans than we thought.
Update: As of 2019, Ysearch is no longer available.
At the end of Thomas’s presentation, he included the image of a tree with a new root and lots of interesting branches.
Zooming in on the branches, you can see all of the DNA sequencing paraphernalia, microplates, readouts and results. Maybe there is a little artist buried someplace in Thomas amid those scientific genes!
This work was no small feat, and the significance is mind-boggling. This new discovery pushed the date of Y-Adam back a whopping 67% in one fell swoop. Cruciani’s birth age for haplogroup A1b was 140,000 years ago and A00, compared to Cruciani’s sample, falls at 237,000 years ago.
Dr. Michael Hammer at the University of Arizona reanalyzed the haplogroup A tree and root with the new information available, and his new ages are even more amazing. Cruciani’s A1b/A0 sample is now at 200,000 years old and A00 is at 338,000, with a 98% confidence level.
These dates pre-date all human fossils, although there are some archaic fossils that have been found and dated after this time in neighboring Nigeria. This new information provides us with glimpses through the keyhole of time into ancient human origins, and begs even more questions that will be answered in time, with more genetic and anthropology research. We all descend from this common root, and we may all be more closely related to archaic man that we knew.
The A00 participant descends from a former slave family in South Carolina. The closest matches are found in western Cameroon near the Gulf of Guinea, a prime location in the slave trade.
There appears to be about 500 years between the participant and the samples from Cameroon, an age that speaks to the beginning of the slave trade.
Having worked closely with Lenny Trujillo, the man whose WTY sample provided us with haplogroup-changing and defining information for haplogroup Q, and understanding what a moving experience this journey has been for Lenny, I wondered about how the family involved with this revolutionary discovery must feel.
As luck would have it, I have worked with this family in one of my projects as well, and they contacted me after seeing my blog about the conference.
I asked how they felt, how they were reacting to this history-changing event in which their family was the keystone. I have extracted pieces from e-mails back and forth, and with the families permission, am sharing what they had to say. Clearly, without them and their active and supportive participation, this discovery would not have been made. We all owe them a debt of gratitude.
“I have a B.S. in Mathematics. I love science and learning. I recently retired, but I spent a lot of that time working with research scientists on cutting edge technology and methods so it is very exciting to me to be a part of such a scientific discovery. My family would say I was the right one chosen. This is the family line I know the most about so I am glad it was this part of my family.
I don’t yet have the formal results from Family Tree DNA concerning the Y-DNA sample they tested in the Walk Through the Y, I did know that the discovery was monumental from some preliminary results from Thomas.
I wanted to see the tie back to Africa, looks like GOD did exceedingly, abundantly more than I could ever ask or think. Just think of how long HE has preserved this Y-lineage just for such a time as this.”
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