I don’t follow closely, but one of the truisms of human genetics has been the impact of the Toba Eruption.

DNA studies seem to show modern humans are descended from a smaller than expected number of people. We seem to have lost some of the genetic diversity we would be expected to have.

One possible explanation is that there was a point in human history, maybe about 50 thousand to 100 thousand years ago, when the number of humans dropped dramatically. The cause of the drop was perhaps the eruption of the Toba Supervolcano about 75 thousand years ago. Fun, fun.

But no. Now they’re thinking maybe not.

I’m sad to lose such an interesting theory, but it is what it is.

• PBS Eon, “How a Supervolcano Ignited an Evolutionary Debate,” YouTube, Sept. 23, 2021.

I decided recently to have a Full mtDNA test at Family Tree DNA (FTDNA). This is something I’ve been putting off. I had the HVR1 test at Oxford Ancestors in 1998, and another at FTDNA in 2007. In between, I also donated a blood sample to BYU. Those results ended up at the now defunct Sorenson Molecular Genetics (SMGF).

I don’t have enough matches to make this more detailed test useful. No one is going to make a genealogical breakthrough by comparing results with me. I belong to Haplogroup V2, a common British group, perhaps with origins in Doggerland.

This full test gave me nothing new. I was (predicted) V2 at FTDNA, now I’m confirmed. But I was already confirmed V2 at SMGF. No new subgroup. I got a few new matches, that’s it.

But, I might need to back off a bit. I have my DNA results uploaded at WikiTree. They have mangled my maternal line–and they’ve been quite insulting about it. I probably need to pull my results so the link isn’t leading other researchers astray. What part of no evidence means no evidence? WikiTree does a hard sales pitch about requiring evidence. It’s even in the Honor Code. But when it comes to unsourced and inaccurate data, nothing can be done. They just shrug. Oh well. It’s not like evidence matters in genealogy.

We’ve had all these little hints over the years, now here’s the confirmation. Viking expansion funneled greater genetic diversity into Scandinavia, according to new study published in the journal Nature.

“The ongoing exchange of goods, people and ideas encouraged Vikings to interact with populations across Europe—a trend evidenced by the new survey, which found relatively homogenous genetic information in Scandinavian locations like mid-Norway and Jutland but high amounts of genetic heterogeneity in trade hubs such as the Swedish islands of Gotland and Öland.”

In the face of racial-purity nuts, I’ve joked for years that my Viking ancestors surely brought back exotic wives and concubines from all over Europe. Because my ancestors were Swedish, they would have viked over to Russia and down to the slave markets of Byzantium. I’d be surprised if a lot of that diversity didn’t make it back home.

• Tara Wu. “Sweeping DNA Survey Highlights Vikings’ Surprising Genetic Diversity.” Smithsonian Magazine <smithsonianmag.com>, Sept. 18, 2020.

I think we could file this one under “proving the obvious”. Some South American Indians share DNA with some Polynesians. And the connection goes back way before European contact.

I was a fan of Thor Heyrdahl when I was a kid. I must’ve read Kon-Tiki a dozen times. That’s the one where he built a raft and sailed from Peru to Polynesia because he thought the Pacific Islands might have been settled by people from South America.

That was a controversial theory. Not accepted by academics, but still intriguing because it was something that could have happened, even if it didn’t really.

I secretly held onto hope there might be a kernel of truth. Then it turned out in 2013 that sweet potatoes spread from South America to Polynesia in historic times, say about 1000 to 1100 CE. The articles published back then were mostly hellbent on explaining that Heyerdahl was still an idiot and sweet potatoes were probably set adrift after a typhoon. No human intervention needed.

Ja. Maybe so but those sweet potatoes put a big question mark over the orthodox history.

This new DNA evidence can be explained by a single contact. It doesn’t validate Heyerdahl’s theory that Polynesians originated in South America, but it’s a fun and interesting validation of the core idea.

• Nectar Gan, Indigenous Americans had contact with Polynesians 800 years ago, DNA study confirms, CNN <cnn.com>, July, 9, 2020, retrieved July 9, 2020.