Listing Criteria for SNP Inclusion
into the ISOGG Y-DNA Haplogroup Tree - 2007

The entire work is identified by the Version Number and date given on the Main Page.   Directions for citing the document are given at the bottom of the Main Page.
Version History     Last revision date for this specific page: 25 July 2007

LINKS:  Main Page   Y-DNA Tree Trunk   SNP Index   Papers Cited   Glossary  
  1. These recommendations are to assure that there is a uniform set of criteria for accepting binary polymorphisms for defining and placing clades on the ISOGG Y-Chromosome Haplogroup Tree. We define binary polymorphism (BP) as a polymorphism with two states. It could be a single nucleotide polymorphism (SNP) or an insertion/deletion (indel).

  2. While not a part of the definition for binary polymorphism, it is expected that the markers proposed for inclusion as defining markers for haplogroups will also have the characteristics: (a) the effective mutation rate will be less than approximately 5 x 10-7, and (b) that the polymorphism has not been observed more than twice in human history.

  3. To be accepted the BP has to be observed at least twice in separate individuals and satisfy either the frequency or STR diversity requirements to exclude the BP from being classified as private (as defined in section 12).

  4. In exceptional cases other variants may be considered for inclusion on a case by case basis if they can be clearly demonstrated to have an allele state or range with equivalent properties to binary markers, but the burden of proof required will be much higher and at the discretion of the committee.

  5. We would like to avoid the inclusion of new binary polymorphisms where it is not clear how they relate to previously established binary polymorphisms.

  6. Non-Terminal Branch BPs

    1. The supporting information provided by the proposer should demonstrate that the new BP is downstream of an established BP and has been tested in individuals who have also been tested for all potential (well established and non-private) downstream BPs.

    2. For example, suppose that a new BP is discovered and that it is claimed to be 1) within Haplogroup F and 2) ancestral to both Haplogroups G and H, but not to I, J, or K. Then several persons should have been tested to demonstrate that those who are confirmed as being in either Haplogroup G or Haplogroup H are also derived for the new BP, and that at least two persons who are in each of Haplogroups I, J, and K are ancestral for the new BP. The individuals tested in each group also need to be unrelated. The test for unrelatedness here and elsewhere will be the provision of an associated STR haplotype whose allele values differ in 15% or more of the markers genotyped.

  7. Terminal Branch BPs

    1. In the case where the new BP is the terminal branch of an existing clade that already has existing sub-branches, then:

      1. at least 2 unrelated individuals that are derived for the new BP need to be tested for every existing sub-branch (i.e. sister clade) defining BP, with the exception of private BPs (see section 12), and shown to be ancestral for these sister clade BPs.

      2. at least 2 unrelated individuals that are derived for each sister clade BP are tested with the new BP and shown to be ancestral.

    2. In the case where the new BP is the new terminal sub-branch of an existing terminal BP, then it should also be demonstrated that it is not restricted solely to close relatives. This can be achieved by demonstrating that two or more derived state individuals have greater than 15% mismatches in their associated STR profiles, plus any results where the ancestral state of the BP was detected.

  8. Acceptance Process

    1. The ISOGG committee will accept proposed new BPs in a two-step process. First the discoverer of the BP (or a third party, knowledgeable about the BP) can email Whit Athey or John McEwan and describe where the new BP fits in the cladogram. The committee can tentatively incorporate this BP according to this advice and make any structural changes to the haplgroup tree necessitated by it. The discoverer (or third party) then would provide the evidence as stated above for the proposed placement within the period of one month from the provisional placement on the tree. Therefore, new BPs should not be submitted until this deadline is a reasonable one. When the additional information is received, the BP would be classified as either added (full confirmation) if full evidence as described above was available, or confirmed (within subclade) if sufficient information was available to meet that requirement (see below). In the latter case it would be expected that when sufficient additional evidence was collected it would be provided and the BP would move to added (full confirmation).

  9. Provisional BPs are color coded and defined as: BPs newly submitted to the ISOGG committee that have sufficient information to be placed in the tree with some certainty, but insufficient to meet all the criteria above and are awaiting evidence as described above.

  10. Confirmed BPs are color coded and defined as: BPs that have met all of the criteria listed above for inclusion.

  11. Confirmed BPs are color coded and defined as: BPs that have at least 20 individuals tested within their final subclade, plus at least 2 derived individuals. However, derived individuals for all existing branches within the subclade (i.e. sister clades) have yet to be tested.

  12. Private SNPs are color coded and are defined as:

    1. EITHER a BP that has been observed only once, or has been observed multiple times but the associated STR profiles show less than 15% of markers have diverged.

    2. OR a BP for which NO specified population have been demonstrated to exist where the frequency is greater than 0.05% (P<0.05) and whose total male population exceeds 500 thousand individuals as defined geographically or ethnically.

Corrections/Additions made since 20 December 2006:

Back to Main Page
Back to Y-DNA Tree Trunk
Back to SNP Index
Back to Papers Cited
Back to Glossary

Copyright 2007, International Society of Genetic Genealogy. All Rights Reserved.