Linda Clyde | Jun 14, 2018

Using DNA to Discover Your Deep Ancestry

This is the second of a three-part series about finding the right DNA test for you. Read part one and part three to learn more.

Today, people want to use DNA tests for a variety of reasons. The most common reason is to find living relatives but according to Jim Brewster of Family Tree DNA there are other folks out there who are less interested in connecting with long-lost relatives than they are about discovering their distant roots and cultures. As he put it, some people just want to know whether they should be wearing lederhosen or a kilt.

Learning about your deep ancestry requires looking at your DNA from a different angle and modern DNA testing is making new and exciting advances all the time. In Brewster’s 2018 RootsTech presentation he explained many aspects of DNA in detail, including two types of DNA called “STRs” and “SNPs”. STRs are used for modern relative finding and matching purposes, where SNPs, (single nucleotide polymorphisms) are used for tracking ancestral migrations and discovering deep ancestral information, such as haplogroups.

A haplogroup is a grouping of people that share a common ancestor and are connected to a specific family line often dating back many thousands of years. Genetic scientists believe the oldest known humans originated from eastern Africa and from there they spread throughout the world. As they spread, different mutations occurred in the DNA and distinct differences began to emerge setting the groups apart from one another. Commonly studied are the Y-chromosome DNA haplogroups and the mitochondrial DNA haplogroups. Y-chromosome DNA follows the male (patrilineal) line, from father to father to father. The mitochondrial DNA follows the female (matrilineal) line but is passed to both sexes, male and female. All children receive mitochondrial DNA from their mothers only.

By carefully studying and labeling haplogroups over the years, scientists can trace DNA back to what they call “Y Chromosomal Adam,” which is different from the Biblical Adam, and also “Mitochondrial Eve”—again, different from Biblical Eve. Using mitochondrial DNA scientists have discovered that every living human being can trace their ancestry back to “Mitochondrial Eve.” The genetic Adam and Eve are not necessarily the first humans, but they are both recognized as the most recent common ancestors, or MRCA’s of the living human race. Brewster recommends joining a haplogroup project for anyone who had taken a Y-DNA or mtDNA test, as this can help a great deal in understanding the results.

What about discovering the regions of your deep ancestry? Family Tree DNA offers a My Origins feature with their Family Finder (autosomal) DNA test. The results from this test provide a breakdown in the form of a percentage of the genetic populations (regions) to which your autosomal DNA is connected. It won’t give you an actual country, and there’s a good reason for that—over time, countries change. Brewster gives an example saying, “You could be living in the same location one year, and be in, say, Prussia. And then the next year, all of a sudden you’re in Czechoslovakia. Does that mean that your DNA has changed, or that your sense of identity has changed? No, it’s that the political border has changed.”

Brewster also brings up reference populations, or reference panels, which are groups of people that have lived in one place for a very long time. Finding groups that have been more isolated from outside groups for long periods of time reveal markers that are unique to that particular group and can be valuable for referencing. But no matter how isolated any group seems to be, and no matter how long they have lived in an area, the truth is, they came from somewhere else, “because we’re all migrants if we go back far enough,” said Brewster.

When it comes to migration, Brewster suggested a visual exercise for attendees when he said, “Think of a map of Europe as being sort of a three-dimensional map. And you drop a marble on it, and you start rolling it around. Well that marble is going to roll pretty much anywhere that there isn’t a major geographical border. That there isn’t a mountain, or a lake, or things like that. And that’s sort of analogous to migrations of people. You have people who are traveling all over, for trade, for new farmland, for things like that. But you know, when people travel, they also meet other people along the way. And you know, genes tend to mix. And so, instead of it being sort of distinct one from another … there’s some overlap between them.”

It’s important to remember that while genetic genealogy is taking great strides and providing us with exciting information, the science is still young and evolving. Brewster reminded those attending his presentation that “each company has its own set of reference populations or reference panels. So there’s going to be differences in just the markers alone, and then there’s going to be differences in the algorithms that each company uses to analyze that. … So it’s not that the results are wrong, or that one test is better than another. It’s that we’re still working on what works, what doesn’t work, [and] how we can improve it. … It’s only going to get better, and it’s only going to get more accurate. …” This is exciting news for those who are looking forward to learning more about their deep ancestry. If this is you, keep your eye on the DNA horizon, exciting things are surely coming your way in the not-so-distant future!

This is the second of a three-part series about finding the right DNA test for you. For more, read part one.

Linda Clyde

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