By: Katy Rowe-Schurwanz

Editors Note: This is part one of a five-part series about what Y-DNA is, what Y-DNA can tell you, and how to apply Y-DNA results to your genealogy. Read the rest of the series here:

Exploring your paternal lineage uncovers a treasure trove of family history. Y-DNA testing, pioneered by FamilyTreeDNA since 2000, guides this journey. You can discover new ancestors and validate family connections by testing your Y-DNA. Learn about the evolution of Y-DNA testing and the advancements reshaping our understanding of paternal ancestry.

So, what exactly is Y-DNA?

Y-DNA, in the simplest terms, is passed down from father to son from the Y chromosome. But why does Y-DNA matter so much in genealogy? Through Y-DNA testing, your Y-DNA allows you to trace your direct paternal line. Y-DNA testing allows you to discover more about your father’s story, from uncovering new ancestors to confirming your paper trail to finding where your paternal ancestors came from.

Y-DNA testing started with FamilyTreeDNA

FamilyTreeDNA was one of the first direct-to-consumer DNA testing companies to offer testing for genetic genealogy, starting in 2000. In May 2000, FamilyTreeDNA launched our first Y-DNA test, which only covered 12 short tandem repeats (STRs). FamilyTreeDNA quickly added the Y-25, examining 25 STRs by 2002, followed by the Y-37 in 2003, the Y-67 in 2006, and the Y-111 in 2011. In 2019, FamilyTreeDNA discontinued the Y-25 and Y-67 tests.

Other companies offering early testing were Sorenson’s SMGF, Oxford Ancestors, and GeneTree, which was sold to Sorenson’s SMGF. Sorenson and GeneTree were sold to Ancestry in 2012; however, Ancestry destroyed their Y-DNA database in 2014, and Oxford Ancestors destroyed theirs in 2018.

What is the Y-DNA Haplotree?

The Y-DNA Haplotree is a map that tracks and traces all the mutations on the Y chromosome back to the earliest known male ancestor.

In 2002, the Y Chromosome Consortium (YCC) began producing and maintaining a Y-DNA haplotree. The first haplotree was comprised of 245 single nucleotide polymorphisms (SNPs) and 153 branches. The YCC expanded its haplotree in 2008 to include 599 SNPs and 311 branches. Their final update in 2010 contained 440 branches.

FamilyTreeDNA began offering SNP tests in 2004, with early options including Deep Clade panels, which were replaced with SNP packs and individual SNP tests in 2014.

The Y-DNA Haplotree grew as Y-DNA became easier to test

In 2005, National Geographic launched the Genographic Project in partnership with FamilyTreeDNA. The first phase of the Genographic Project covered 12 STRs, which could be transferred to FamilyTreeDNA for matching. Later phases of the Genographic Project’s test covered only enough Y-DNA to provide a haplogroup and, while still available to transfer to FamilyTreeDNA, did not cover enough to provide matching. The Genographic Project stopped offering its tests in 2019 and deleted its database in 2021.

By 2007, both the Daughters of the American Revolution (DAR) and the Mayflower Society began accepting Y-DNA evidence as proof of connection to ancestors for admittance to those groups.

In 2010, FamilyTreeDNA offered an exploratory SNP test called Walk the Y. Walk the Y used Sanger sequencing to explore between 300,000 and 600,000 Y-DNA SNPs. This test was discontinued in 2013, leading up to the launch of the Big Y test.

In 2014, FamilyTreeDNA began offering the Big Y, which used Next Generation Sequencing (NGS) to examine the Y chromosome. The first version of the Big Y was available only as an upgrade from a previous Y-STR test and did not include any additional Y-STR testing.

In 2018, all Big Y tests were upgraded to the Big Y-500, which added 379+ STRs above the 111 panel to the SNP results. In 2019, the Big Y-700 was launched, which introduced new sequencing technology, offering 50% more SNP coverage than the Big Y-500, along with up to 868 STRs including the 111 panel.

The Big Y tests caused exponential growth of the Y-DNA haplotree. FamilyTreeDNA launched our Y-DNA haplotree in 2014. This new haplotree included an update to the SNP nomenclature from longhand haplogroups to shorthand haplogroups (for example, testers would no longer receive the longhand haplogroup R1b1a2, but instead the shorthand R-M269).

Haplotree growth after the launch of the Big Y:

  • May 2015: 6,556 SNPs
  • Nov 2016: 23,767 SNPs
  • Nov 2017: 58,590 SNPs
  • May 2018: 100,000 SNPs
  • Dec 2019: 200,000 SNPs, 20,000 branches
  • December 2020: 350,000 SNPs, 35,000 branches
  • May 2021: 400,000 SNPs, 40,000 branches
  • December 2021: 50,000 branches
  • October 2022: 60,000 branches
  • July 2023: 70,000 branches

The haplotree is on track to surpass 80,000 branches and 700,000 SNPs in 2024.

A chart showing the haplotree growth after the launch of Big Y

Because multiple companies offered Y-DNA testing early on, sites where Y-DNA data could be transferred for matching were also created. FamilyTreeDNA offered one of these, YSearch, from 2003 until May 2018. The third-party, nonprofit MitoYDNA.org was launched in 2017 and remains an active place for testers to transfer today.

Y chromosomal inheritance can help trace paternal lines

The nucleus of the cell contains DNA passed down from your parents to you—everything except the mitochondria. That means the nucleus is where you find your 22 pairs of autosomes, the X chromosome, and if you’re a genetic male, the Y chromosome, which is where we find Y-DNA.

While you inherit one copy of each autosome from each of your parents, the X and the Y are a little different. Everyone receives an X chromosome from their mother. If you’re female, you’ll inherit another X chromosome from your father. If you’re male you’ll instead inherit your father’s Y chromosome.

A graphic showing how chromosome inheritance works

The Y chromosome doesn’t randomly recombine like autosomal DNA does. However, mutations do happen over time.

With Y-DNA testing, we compare your mutations to others in the database to discover matches and your haplogroup. Those matches are going to share a common ancestor on your direct paternal line because that’s where the Y chromosome comes from. Mutation differences between matches can estimate when that common ancestor lived.

Success in matching comes down to two things:

  1. The number of mutations tested (essentially, the more of your Y chromosome tested, the more specific and precise your results will be and the greater your chance of finding not just matches but close matches)
  2. The chance that others on your direct paternal line have also tested

Take a Y-DNA test and find your place on the Y-DNA Tree of Mankind

With each advancement, like the Big Y test, FamilyTreeDNA propels the exploration of paternal lineage. As the Y-DNA haplotree expands, our understanding of human migration and lineage deepens. Whether you’re new to genetic genealogy or refining your ancestral narrative, FamilyTreeDNA provides powerful tools to navigate your paternal lineage and find your place in history.

Headshot of Katy Rowe-Schurwanz - Product Manager at FamilyTreeDNA

About the Author

Katy Rowe-Schurwanz

Product Manager at FamilyTreeDNA

Katy Rowe-Schurwanz has always been interested in genealogy, inspired by her maternal grandparents, who told her stories about their family and family history when she was little. After studying anthropology and history in college, she joined FamilyTreeDNA in 2015 and became the Trainer for Customer Support. Katy created and improved training processes and was fundamental in the creation of the Big Y Specialist team. In September 2021, she became Product Manager and has focused closely on improving FamilyTreeDNA’s genetic genealogy products.