Some Family Tree DNA Participants will find their haplogroup designation changed to the new nomenclature on May 5th.
While the name of the haplogroup a person belongs to may change, and will continue to change as more haplogroup branches are discovered and published, their actual DNA testing results and interpretation remain the same. The next issue of the Family Tree DNA newsletter, Facts and Genes, will discuss these changes in more depth and should help you better understand the changes to the Y-DNA haplogroup tree.
The Family Tree DNA website will be temporarily offline on Monday, May 5th, at 5 am CDT to facilitate this update in nomenclature and other maintenance. Service will be restored no later than 7 am CDT that day. Ysearch.org, our free publicly accessible website, will be offline and updated simultaneously.
If you would like more information about why the haplogroup nomenclature is changing and what this means to you, please visit the FAQ site below:
Public release date: 1-Apr-2008
Scientists reshape Y chromosome haplogroup tree gaining new insights into human ancestry
Wednesday, April 2, 2008 –The Y chromosome retains a remarkable record of human ancestry, since it is passed directly from father to son. In an article published online today in Genome Research (www.genome.org), scientists have utilized recently described genetic variations on the part of the Y chromosome that does not undergo recombination to significantly update and refine the Y chromosome haplogroup tree. The print version of this work will appear in the May issue of Genome Research, accompanied by a special poster of the new tree.
Human cells contain 23 pairs of chromosomes: 22 pairs of autosomes, and one pair of sex chromosomes. Females carry a pair of X chromosomes that can swap, or recombine, similar regions of DNA during meiosis. However, males harbor one X chromosome and one Y chromosome, and significant recombination between these dissimilar sex chromosomes does not occur. Therefore, the non-recombining region of the Y chromosome (NRY) remains largely unchanged over many generations, directly passed from father to son, son to grandson, and so on, along with genetic variations in the NRY that may be present. Scientists can use genetic variations, such as single nucleotide polymorphisms (SNPs), on the Y chromosome as markers of human ancestry and migration.
In 2002, the Y Chromosome Consortium (YCC) constructed a tree of 153 haplogroups based upon 243 unique genetic markers. In this report, researchers led by Dr. Michael Hammer of the
Hammer’s group integrated more than 300 new markers into the tree, which allowed the resolution of many features that were not yet discernable, as well as the revision of previous arrangements. “The major lineages within the most common African haplogroup, E, are now all sorted out, with the topology providing new interpretations on the geographical origin of ancient sub-clades,” describes Hammer. “When one polymorphism formerly described as unique, but recently shown to have reversed was replaced by recently reported markers, a sub-haplogroup of haplogroup O, the most common in
In addition to improving the resolution of branches, the latest reconstruction of the tree allows estimates of time to the most recent common ancestor of several haplogroups. “The age of [haplogroup] DE is about 65,000 years, just a bit younger than the other major lineage to leave
Furthermore, Hammer explains that this work has resulted in the addition of two new major haplogroups, S and T, with novel insights into the ancestry of both. “Haplogroup T, the clade that Thomas Jefferson’s Y chromosome belongs to, has a Middle Eastern affinity, while haplogroup S is found in
“More SNPs are being discovered, and we anticipate the rate to increase with the 1000 Genomes Project,” says Hammer, referring to the wealth of human genetic variation data that will soon be available. While this report represents a significant advance in mapping ancestry by Y chromosome polymorphisms, it is certain that future discoveries will necessitate continual revisions to the Y chromosome haplogroup tree, helping to further elucidate the mystery of our origins.
Scientists from the
This work was supported by the Salus Mundi Foundation.
Michael Hammer, Ph.D., has agreed to be contacted by email for more information (firstname.lastname@example.org).
Interested reporters may obtain copies of the manuscript from Peggy Calicchia, Editorial Secretary, Genome Research (email@example.com; +1-516-422-4012).
About the article:
The manuscript will be published online ahead of print on April 2, 2008. Its full citation is as follows: Karafet, T.M., Mendez, F.L., Meilerman, M.B., Underhill, P.A., Zegura, S.L., and Hammer, M.F. New binary polymorphisms reshape and increase resolution of the human Y-chromosomal haplogroup tree. Genome Res. doi:10.1101/gr.7172008.
About Genome Research:
Genome Research (www.genome.org) is an international, continuously published, peer-reviewed journal published by Cold Spring Harbor Laboratory Press. Launched in 1995, it is one of the five most highly cited primary research journals in genetics and genomics.
Genome Research issues press releases to highlight significant research studies that are published in the journal.