-DNA Haplogroup Nomenclature FAQ


What is a haplogroup?
A haplogroup is defined as all the male descendants of the single person who first showed a particular mutation, called a SNP. These special mutations are extremely rare, and identify a group of people over a period of tens of thousands of years. Your haplogroup assignment indicates which part of the phylogenetic tree of male Homo Sapiens you descend from.

Why do haplogroups change?
The haplogroup network is still evolving as the world?s anthropologists discover more SNP mutations, which define more haplogroup branches and help us to understand how the haplogroups are interrelated. Haplogroups are named based on how they fit within the haplogroup tree. As we learn more about how haplogroups are connected, and discover more SNPs, haplogroup names will be adjusted accordingly.

Does this mean my test result was wrong or inconclusive?
No. The results of your Y-DNA test are definite and are not subject to change. If you have had additional testing to determine your haplogroup, your SNP test results likewise are definite and are not subject to change. The only thing that has changed is the name of the haplogroup to which you belong, which changes as our understanding of the family tree of mankind grows.

Why is my haplogroup with the Genographic Project different from the one with Family Tree DNA?
Recently, researchers led by Dr. Hammer, Family Tree DNA?s Chief Scientist, published the newly updated Y chromosome haplogroup tree in Genome Research. This paper recommends a number of changes in haplogroup nomenclature. Some organizations will adjust to this nomenclature sooner than others, as this may represent significant changes in their database, website, and display to customers.

As of May 5th, 2008, Family Tree DNA has adjusted its haplogroup names to match the newer nomenclature recommended by this research. The Genographic Project will make a similar transition in late 2008.

You may view the older and newer Y-Chromosome Phylogenetic Trees at the links below: