A haplogroup is a genetic population group of people who share a common ancestor on the patrilineal or matrilineal line. Haplogroups are assigned letters of the alphabet, and refinements consist of additional number and letter combinations.
Y chromosome DNA haplogroups
Y chromosome DNA (Y-DNA) haplogroups are determined by single-nucleotide polymorphism (SNP) tests. SNPs are locations on the DNA where one nucleotide has "mutated" or "switched" to a different nucleotide.
Because a haplogroup consists of similar haplotypes, it is possible to predict a haplogroup from the haplotype. A SNP test is required to confirm the haplogroup prediction. Not all the testing companies offer SNP testing, and consequently their customers' haplogroup predictions are sometimes inaccurate.
ISOGG maintains the most up-to-date version of the Y-SNP tree. The tree is updated as and when new branch-defining SNPs are discovered. The criteria for inclusion of SNPs in the tree are published here.
Phylotree maintains a minimal reference phylogeny for the human Y chromosome, an abbreviated version of the Y-tree showing only the principal branches. The Phylotree Y tree can be found here. Background information on the methodology of the tree and the SNPs included can be found here.
There are a number of tools that can be used to predict the Y-DNA haplogroup. For a full list see the ISOGG Wiki page Y-DNA tools.
Y-DNA haplogroup resources
- ISOGG Y-SNP tree
- Phylotree's Y-tree A minimal reference phylogeny for the human Y-chromosome
- The YFull version of the Y-SNP tree
- Y-SNPs and haplogroups DNA Heritage masterclass N.B. DNA Heritage was acquired by Family Tree DNA in 2012.
- Y haplogroups brief descriptions and regonal origins
- Wikipedia page on human Y-chromosome DNA haplogroups
- Y haplogroups of the world
- Y-DNA haplogroup projects
- Y-DNA Haplogroup ages
- SNP testing
- BritainsDNA Y-DNA haplogroup nicknames
- Haplogroup J2a (Y-DNA)
- Haplogroup R1b (Y-DNA)
- Y Chromosome Consortium
Mitochdondrial DNA haplogroups
When you have taken a mitochondrial DNA (mtDNA) test most companies will give you a prediction of your mtDNA haplogroup. The haplogroup can however only be confirmed by testing specific branch-defining single-nucleotide polymorphisms (SNPs), some of which are only found in the coding region. If no SNP tests are done there is a possibility that the prediction will be incorrect. mtDNA tests from Family Tree DNA (HVR1 and HVR2) and the Genographic Project version 1 (HVR1) include a panel of 22 SNPs to confirm the base haplogroup.
The most up-to-date version of the mtDNA tree is maintained by Mannis van Oven on the Phylotree website.
mtDNA haplogroup resources
- Phylotree The phylogenetic tree of global human mitochondrial DNA variation
- FTDNA's list of mtDNA haplogroup-defining mutations
- An mtDNA view of the peopling of the world by Homo sapiens (Internet Archive version)
- Wikipedia page on human mitochondrial DNA haplogroups
- Wikipedia list of haplogroups of historical and famous figures
- Understanding haplogroups by Steve Handy. DNA Genealogical Experiences and Tutorials blog, 3 November 2012.
- History of Y-DNA and mtDNA haplogroups from Eupedia
- The Journey of Mankind: the Peopling of the World an interactive map from the Bradshaw Foundation
- Understanding correlations and debunking misconceptions in DNA genealogy by Steve Handy. DNA Genealogical Experiences and Tutorials blog, 29 May 2013.