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Haplogroup T (Y-DNA)

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Haplogroup T (Y-DNA) - Eupedia
Contents

Author: Maciamo.
Last update December 2013 (revised map and history)

Geographic distribution

Haplogroup T is a fairly rare lineage in Europe. It makes up only 1% of the population on most of the continent, except in Greece, Macedonia and Italy where it exceeds 4%, and in Iberia where it reaches 2.5%, peaking at 10% in Cadiz and over 15% in Ibiza. The maximal worldwide frequency for haplogroup T is observed in East Africa (Eritrea, Ethiopia, Somalia, Kenya, Tanzania) and in the Middle East (especially the South Caucasus, southern Iraq, south-west Iran, Oman and southern Egypt), where it accounts for approximately 5 to 15% of the male lineages. Besides these regions and Europe, T is found in isolated pockets as far as Central Asia, India, Cameroon, Zambia and South Africa. Its highest density is actually found among the Fulani people of Cameroon (18% of the population).

Distribution of haplogroup T in Europe, the Middle East and North Africa

Distribution of haplogroup T in Europe


Subclades

  • T (L445, M184)
    • T1 (L206)
      • T1a (M70)
        • T1a1 (L162)
          • T1a1a (L208)
            • T1a1a1 (P77)
            • T1a1a2 (P321)
              • T1a1a2a (P317)
        • T1a2 (L131)
          • T1a2a (P322, P328)
          • T1a2b (L446)
        • T1a3 (L1255)

Origins & History

Haplogroup T originated some time between 15,000 and 22,000 years ago, making it a relatively young haplogroups. T is descended from haplogroup K, the ancestor of most of the Eurasian haplogroups (L, N, O, P, Q, R and T), and whose origins are thought to lie in the Middle ast or in Central Asia.

Although haplogroup T is more common today in East Africa than anywhere else, it almost certainly spread from the Fertile Crescent with the rise of agriculture. Indeed, the oldest subclades and the greatest diversity of T is found in the Middle East, especially around the Fertile Crescent.

The higher frequency of T in East Africa would be due to a founder effect among Neolithic farmers or pastoralists from the Middle East. One theory is that haplogroup T spread alongside J1 as herder-hunters in the Pre-Pottery Neolithic period, leaving the Zagros mountains between 9,000 and 10,000 BCE, reaching the Egypt and the southern Arabian peninsula around 7,000 BCE, then propagating from there to the Horn of Africa, and later on to Madagascar. However, considering that J1 peaks in Yemen and Sudan, while T1 is most common in southern Egypt, Eritrea and Somalia, the two may not necessarily have spread together. They might instead have spread as separate nomadic tribes of herders who colonised the Red Sea region during the Neolithic, a period than spanned over several millennia. Nevertheless both are found in all the Arabian peninsula, all the way from Egypt to Somalia, and in Madagascar. This contrasts with other Near Eastern haplogroups like G2a and J2, which are conspicuously absent from East Africa, and rare in the Arabian peninsula.

The modern distribution T in Europe strongly correlates with a the Neolithic colonisation of Mediterranean Europe by Near-Eastern farmers, notably the Cardium Pottery culture (5000-1500 BCE). Its frequency mirrors that haplogroup J1 in Europe as well, both haplogroups being most common in the mountainous parts of the Balkans, the central and southern Apennines in Italy, Sicily, the Massif Central in France (Auvergne), and south-western Iberia. All these regions would have been better suited for goat and sheep herding than for cereal cultivation in the Neolithic period. Mountainous regions allow herders to practice transhumance, i.e. the seasonal movement of people with their livestock between fixed summer and winter pastures.

During the Chalcolithic and Bronze Age haplogroup T would have been an important (though probably not dominant) lineage among ancient peoples such as Sumerians, the Babylonians and the Assyrians.

The higher than average frequencies of haplogroup T in places like Cyprus, Sicily, Tunisia, Ibiza, Andalusia and the northern tip of Morocco suggest that haplogroup T could also have been dispersed around the Mediterranean by the Phoenicians (1200-800 BCE), and that ancient Phoenicia seemingly had a higher incidence of T than Lebanon does today (5%).

While almost all subclades of T are found in the Middle East, most Europeans outside the Mediterranean belong to the subclades T1a2 (L131) and T1a1a1a (P77), which are also found in Anatolia. These subclades probably represent one of the Neolithic migration from the Fertile Crescent to Southeast Europe. They would then have spread around central and Eastern Europe, as far north as the eastern Baltic. T1a2 has been found as far east as the Volga-Ural region of Russia and Xinjiang in north-west China. This branch probably penetrated into the Pontic-Caspian Steppe during the Neolithic (perhaps alongside G2a3b1 and J2b2) and became integrated to the indigenous R1a peoples before their expansion to Central Asia during the Bronze Age (=> see R1a-Z93).

Haplogroup T has been found at a relatively high frequency among the Tatars (5%) and Maris (2%) of the Volga-Ural region as well as in north-west Russia (3%) and Estonia (3.5%) suggesting that it may have been one of the principal lineages bringing the Neolithic to Uralic-speaking population. Autosomal DNA tests have also identified unusually high percentages of Southwest Asian admixtures among the Finns (1 to 2.5%) and Lithuanians (1.5%), who otherwise lack West Asian or Caucasian admixture and possess hardly any Middle Eastern Y-DNA. This Southwest Asian admixture could be the trace of T lineages absorbed during the Neolithic.

Famous individuals

The testing of Thomas Jefferson's DNA revealed that the third US president belonged to haplogroup T.

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