Saturday, 5 March 2011

Major update to Y-chromosome tree

The following e-mail has been sent out to all group administrators at Family Tree DNA:
Dear Group Administrator
We are excited to announce that we have updated our Y Chromosome Phylogenetic Tree to reflect new haplogroup sub-branches!
Family Tree DNA, in partnership with the YCC  [Y chromosome consortium], periodically reviews known SNPs in order to evaluate those that meet the requirements to be added to the haplotree. The SNPs that passed this review are now included in the haplotree and considered for deep clade testing.
Along with this update to the tree, we have implemented some changes in the ordering process for deep clade and SNP testing:
  • We now offer a universal deep clade test for $89. This will identify a customer’s terminal SNP for any haplogroup.
  • If a customer has pending results for a deep clade test, they will automatically be tested according to the new tree.
  • If a customer has never ordered a deep clade test, they will have the option either to order the universal deep clade for $89 or order individual SNPs from the tree.
  • We will no longer be offering a deep clade extension product. For customers interested in upgrading to the new tree, it may be more economical to order the universal deep clade for $89 if there are 4 or more new SNPs available to them (each SNP is $29 individually). If there are less than 4 new SNPs available for a customer, they will not be offered the universal deep clade test and should order the SNPs individually from the tree since this is the most cost-effective option. Newly available SNPs are shown on the haplotree in orange.
The most noticeable change with the introduction of the new nomenclature is that the old haplogroup R1b1b2, which accounts for about 70% of the men in the British Isles, has been renamed as haplogroup R1b1a2. For those who are interested in the technical details the reason for this change is that M18, which was previously R1b1bc1, has now been found to be upstream of V88. M18 was discovered in 1997 and therefore took precedence over the two parallel clades P297 (formerly R1b1a) and M335 (formerly R1b1b).  P297 and M335 were published in a paper by Karafat et al in 2008. As M18 was discovered first it therefore takes precedence and becomes R1b1a, causing P297 and M335 to be renamed. In older versions of the R1b tree M18 did in fact appear as R1b1a prior to the discovery of V88 (formerly R1b1c) in a Cruciani paper in 2010. I hope I've understood all that correctly. It all sounds terribly complicated! In reality it is much easier to use the shorthand versions of the haplogroup names such as R1b-P297 which obviates the need to remember all those complicated letters and numbers! The ISOGG Y-SNP tree has now been updated to conform with the new nomenclature and will continue to be updated as new SNPs are discovered. The ISOGG tree can be found here.

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