In
human mitochondrial genetics,
Haplogroup T is a
human mitochondrial DNA (mtDNA)
haplogroup.
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.
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."
[http://www.oxfordancestors.com/content/view/35/55/ Oxford Ancestors Maternal Ancestry] 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."
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."
Subclades
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 and subsequent published research.
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."
The last
Russian
tsar,
Nicholas II, has been shown to be of haplogroup T. 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.
Health Issues
Studies had shown mitochondrial haplogroup T to be associated with reduced sperm motility in males, although these results have been challenged. 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. However, these findings have been disputed.
Some studies have shown haplogroup T to be associated with increased risk for coronary artery disease. However, some studies have also shown that haplogroup T carriers are less prone to diabetes.
A few tentative medical studies have demonstrated that haplogroup T may offer some resistance to both Parkinson's disease and Alzheimer's disease.
See also
