26 October 2022
Take a closer look at the Big Y-700’s emergence, what is being tested, and what you can discover from the results.
The origins of the Haplotree
In 2002, the Y Chromosome Consortium released the first comprehensive tree charting mankind’s migration out of Africa. Dubbed “the haplotree,” this was the first application of genetic testing to human prehistory and anthropology. The haplotree revolutionized our understanding of how humans spread across the globe and how modern populations are related.
What are SNPs?
This haplotree was based exclusively on a type of Y-DNA called single nucleotide polymorphisms or SNPs (pronounced snips). The same is true in the modern haplotree. By comparing the similarities and differences in SNPs between different populations, the consortium was able to distinguish a general timeline of when the populations split and traveled to other regions of the globe.
Each population had SNPs inherited from shared ancestors, and as generations went by, they began to form their own unique SNPs. These new SNPs formed new branches on the tree of humankind. Many of these SNPs were calculated to have originated in ancestors that lived thousands or tens of thousands of years ago. The first haplotree contained fewer than 100 SNPs grouped into 13 branches, a pretty impressive number at the time.
The rate of advancement in identifying new SNPs and branches on the haplotree was slow, limited by the cost and efficiency of testing methods. Over the next 10 years, the haplotree grew to include 3,600 SNPs and numerous branches. These advances helped refine our understanding of how closely related different populations were at a genetic level. This is valuable information for anthropologists, archaeologists, and anyone studying global migrations.
However, the nagging problem of SNP testing is the extreme age estimates between branches. When a branch could be thousands or even tens of thousands of years old, how does it help you understand your own place in the global tree of humanity?
The invention of Y-DNA testing
DNA testing does not take the place of traditional family history research. DNA testing is one of many tools in a genealogist’s toolkit. It can help point you in the right direction and provide clues as to where to search, but those clues and matches need to be fleshed out by paper trail research.
How does the Big Y test work?
NGS technology allows FamilyTreeDNA to process the Big Y-700 samples with the same amount of power as previous technology
Enter FamilyTreeDNA’s Big Y test in 2014, followed by the Big Y-500 in 2017 and the Big Y-700 in 2019. All three tests use a new technology called next-generation sequencing (NGS). With the advent of NGS, we were suddenly able to sequence entire regions of the Y chromosome at a time instead of specific markers. In a single stroke, we could find hundreds of SNPs in the time it took to find just one. People had never before seen SNPs that were unique to them. As more people tested and we found these same SNPs, we were able to reliably add them to the tree in already established branches and create new branches as well.
In the first two years alone, the Y-DNA haplotree nearly doubled in size. In just three, it had grown by nearly 700%. New SNPs were being discovered almost daily, and by November of 2017, FamilyTreeDNA had amassed the world’s largest Y-DNA haplotree at just under 59,000 SNPs.
NGS works by analyzing an entire region of a chromosome rather than specific markers. This means that it will not always detect every single marker, but it has the advantage of discovering previously unknown markers.
The Big Y test looks at a SNP-rich region of the Y chromosome and detects as many SNPs as possible. It covers this area with up to 70 reads to ensure the results are accurate. Any SNP that returns 10 or more positive reads is reported. This helps ensure that potential misreads are caught and corrected. In 2014, with the release of the Big Y, this radical new technology helped grow our knowledge of the Y-chromosome by leaps and bounds.. This explosion in the number of SNPs meant branches were discovered that were hundreds of years old instead of thousands. It was only through a large database of sample results to compare that we were able to distinguish these markers.
The Big Y-500 test
At the advent of the Big Y, Y-STR markers were still the gold standard for comparing male relatives. It was rare when an STR match shared a common ancestor more than 500 years in the past. That made it more valuable for family history than SNPs that were even older.
Testing can show your haplogroup with other more recent branches and branches from thousands of years ago
Unfortunately, it was somewhat hazy where in that 500-year timeframe to search for a common ancestor with a Y-STR match. For this reason, FamilyTreeDNA developed the Big Y-500. This test incorporated both Y-SNP and Y-STR testing.
Coverage of the original Big Y was expanded and altered to include all 111 STRs found in the Y-111 and up to an additional 450 STRs. These 450 STRs were chosen because they were detected in over 95% of control samples. As with SNPs, the exploratory nature of NGS meant that not all 450 STRs would necessarily be detected and meet our quality control standards in every sample. To provide a large group of STRs for genealogists to work with, FamilyTreeDNA committed to rerunning a sample as many times as needed to produce results for a minimum of 389 STRs. These, combined with the 111 standard STRs, provided at least 500, hence the Big Y-500. In addition to the potential brought by these new STRs, expanded coverage of the Y chromosome meant even more SNPs became available for discovery.
The Big Y-700 Test
Always at the forefront of innovation, FamilyTreeDNA continues to explore uncharted waters and grow the Y-DNA haplotree by leaps and bounds. In 2019, we released the Big Y-700 test. This innovation took Big Y back to the drawing board to expand coverage for Y-STRs and Y-SNPs. It expanded the coverage area even more and is discovering new SNPs daily.
What will the Big Y-700 Test tell me?
What does the Big Y-700 test mean for your family history? First, having so many SNPs on the tree means you can potentially find a branch that originated no more than a couple of generations ago. This means you can find markers specific to your lineage and your lineage only. If you have a SNP that originated with your great-grandfather, for example, then anyone else who shares that SNP is a second cousin at the furthest.
This brings genetic testing from just one of many tools to one of the premier tools for genealogists studying paternal lines. The Y-DNA haplotree continues to grow daily. Having such a huge database to draw on has helped revolutionize the age estimates we are able to provide for SNPs. This is done by process of elimination and other factors to produce a time to most recent common ancestor (TMRCA) between any two SNPs.
The Big Y-700 test and FamilyTreeDNA Discover™
Just a few months ago, we released FamilyTreeDNA Discover, a free new platform that provides TMRCA estimates in a user-friendly visual format. Discover provides a reliable estimate of TMRCA between two people based on genetic data (SNPs and STRs) alone, without traditional family trees. Depending on the branch, this estimate can be within 50 years, and half of all testers receive an estimate within the past 500 years or fewer. Such a tool significantly reduces the amount of legwork needed to find a common ancestor and make family connections.
With Discover, you can view different reports like your haplogroup story and notable connections using the confirmed haplogroup from your Big Y-700 test
Discover is currently in beta, and refinements are being made weekly, but it already shows tremendous potential and has received overwhelmingly positive feedback. This platform will only improve over time as more and more SNPs are added.
Lastly, the Big Y-700 test is the test that keeps on giving. When you test, it is likely you will have “novel variants,” meaning new SNPs that we have not yet added to the tree. As the tree grows, these new SNPs will be incorporated, so over time, you will see your place in the tree grow more accurately. There is no additional fee for this, as the data already exists. It really is an exciting time to be a genealogist.
So is the Big Y-700 test worth it? The Y-DNA test that provides full SNP coverage, a confirmed Y-DNA haplogroup, and lifetime analysis? See for yourself by ordering a Big Y-700 test today.