Haplogroup T (mtDNA)

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Haplogroup T
Time of origin approx. 10,000-12,000 years before present
Place of origin Mesopotamia/Fertile Crescent
Ancestor JT
Descendants T1, T2
Defining mutations 709, 1888, 4917, 8697, 10463, 13368, 14905, 15607, 15928, 16294, 16519[1]

Haplogroup T is a human mitochondrial DNA (mtDNA) haplogroup.

Contents

[edit] Origin

Haplogroup T derives from the haplogroup JT, which also gave rise to haplogroup J. Haplogroup T is thought to have originated in Mesopotamia/the Fertile Crescent approximately 10,000-12,000 years ago, and then moved northwest into Europe and east as far as modern Pakistan and India.

[edit] Distribution

Haplogroup T is currently found with high concentrations around the eastern Baltic Sea. According to Oxford Ancestors, Haplogroup T "includes slightly fewer than 10% of modern Europeans. Its many branches are widely distributed throughout southern and western Europe with particularly high concentrations in Ireland and the west of Britain."[2] According to the Genographic Project: "Haplogroup T has a very wide distribution, and is present as far east as the Indus Valley bordering India and Pakistan and as far south as the Arabian peninsula. It is also common in eastern and northern Europe." [3]

[edit] Early agriculturalists

Haplogroup T has been in Europe for less than 12,000 years which makes it the youngest of the mtDNA haplogroups found there. The Genographic Project states that early people with Haplogroup T were likely some of the first agriculturalists and probably comprised the group which first brought agriculture on to the European continent, bringing the "Neolithic Revolution" to Europe; they write: "Although the haplogroup was present during the early and middle Upper Paleolithic, [Haplogroup] T is generally considered one of the main genetic signatures of the Neolithic expansions. While groups of hunter-gatherers and subsistence fishermen had been occupying much of Eurasia for tens of thousands of years, around ten thousand years ago a group of modern humans living in the Fertile Crescent-present day eastern Turkey and northern Syria-began domesticating the plants, nuts, and seeds they had been collecting. What resulted were the world's first agriculturalists, and this new cultural era is typically referred to as the Neolithic. Groups of individuals able to support larger populations with this reliable food source began migrating out of the Middle East, bringing their new technology with them. By then, humans had already settled much of the surrounding areas, but this new agricultural technology proved too successful to ignore, and the surrounding groups quickly copied these new immigrants. Interesting, DNA data indicate that while these new agriculturalists were incredibly successful at planting their technology in the surrounding groups, they were far less successful at planting their own genetic seed. Agriculture was quickly and widely adopted, but the lineages carried by these Neolithic expansions are found at frequencies seldom greater than 20 percent in Europe, the Middle East, and Central Asia." [4]

[edit] Subclades

[edit] Tree

This phylogenetic tree of haplogroup T subclades is based on the paper by Mannis van Oven and Manfred Kayser Updated comprehensive phylogenetic tree of global human mitochondrial DNA variation[1] and subsequent published research.


  • T
    • T1
      • T1a
      • T1b
    • T2
      • T2a
        • T2a1
          • T2a1a
            • T2a1a1
          • T2a1b
      • T2b
        • T2b1
        • T2b2
        • T2b3
          • T2b3a
        • T2b4
        • T2b5
        • T2b6
      • T2c
        • T2c1
          • T2c1a
          • T2c1b
      • T2d
      • T2e
          • T2e1
        • T2e2
      • T2f
        • T2f1
      • T2g

[edit] Popular Culture

In his popular book The Seven Daughters of Eve, Bryan Sykes, who is himself in haplogroup T, named the originator of this group Tara, which means rocky hill in Gaelic. Sykes believes "Tara herself lived 17,000 years ago in the northwest of Italy among the hills of Tuscany and along the estuary of the river Arno."[5]

The last Russian tsar, Nicholas II, has been shown to be of haplogroup T.[6] This was established when genetic testing was done on his remains to authenticate his identity. Assuming all relevant pedigrees are correct, this includes all female-line descendants of his female line ancestor Barbara of Celje (1390-1451), wife of Sigismund, Holy Roman Emperor. This includes a great number of European nobles, including George I of Great Britain and Frederick William I of Prussia (through the Electress Sophia of Hanover), Charles I of England, George III of the United Kingdom, George V of the United Kingdom, Charles X Gustav of Sweden, Gustavus Adolphus of Sweden, Maurice of Nassau, Prince of Orange, Olav V of Norway, and George I of Greece.

The American outlaw Jesse James has been shown to be of subgroup T2.

[edit] Health Issues

Studies had shown mitochondrial haplogroup T to be associated with reduced sperm motility in males, although these results have been challenged.[7]

According to the Departamento de Bioquimica y Biologica Molecular y Celular, Universidad de Zaragoza, haplogroup T represents a weak genetic background that can predispose to asthenozoospermia.[8] However, these findings have been disputed.

Some studies have shown haplogroup T to be associated with increased risk for coronary artery disease. [9] However, some studies have also shown that haplogroup T carriers are less prone to diabetes. [10]

A few tentative medical studies have demonstrated that haplogroup T may offer some resistance to both Parkinson's disease and Alzheimer's disease. [11]

[edit] See also

Human mitochondrial DNA (mtDNA) haplogroups
  most recent common mt-ancestor    
L0 L1 L2 L3   L4 L5 L6 L7
  M N  
CZ D E G Q   A S   R   I W X Y
C Z B F HV   JT P  U
H V J T K Former Clusters IWX

[edit] References

  1. ^ a b van Oven, Mannis; Manfred Kayser (13 Oct 2008). "Updated comprehensive phylogenetic tree of global human mitochondrial DNA variation". Human Mutation 30 (2): E386-E394. PMID 18853457 doi:10.1002/humu.20921. http://www3.interscience.wiley.com/journal/121449735/abstract?CRETRY=1&SRETRY=0. Retrieved on 2009-05-20. 
  2. ^ http://www.oxfordancestors.com/content/view/35/55/ Oxford Ancestors Maternal Ancestry
  3. ^ [1]
  4. ^ [2]
  5. ^ http://www.oxfordancestors.com/content/view/35/55/ Oxford Ancestors Maternal Ancestry
  6. ^ http://isogg.org/famousdna.htm ISOGG's Famous DNA
  7. ^ http://www.familytreedna.com/pdf/Mishmar2003.pdf Natural selection shaped regional mtDNA variation in humans
  8. ^ Ruiz-Pesini E, Lapeña AC, Díez-Sánchez C, et al. (September 2000). "Human mtDNA haplogroups associated with high or reduced spermatozoa motility". Am. J. Hum. Genet. 67 (3): 682–96. doi:10.1086/303040. PMID 10936107. 
  9. ^ [3]
  10. ^ [4]
  11. ^ [http://www.jogg.info/21/Pike.html "Elsewhere it has been reported that membership in haplogroup T may offer some protection against Alzheimer Disease (Chagnon et al. 1999; Herrnstadt et al. 2002) and also Parkinson's Disease (Pyle et al. 2005), but the cautionary words of Pereira et al. suggest that further studies may be necessary before reaching firm conclusions."

[edit] External links

Retrieved from "http://en.wikipedia.org/wiki/Haplogroup_T_(mtDNA)"
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