Haplogroup T (mtDNA)

Haplogroup T
Possible time of origin	25,149 ± 4,668 Years Before Present
Possible place of origin	Mesopotamia / Fertile Crescent (modern Syria / Turkey)
Ancestor	JT
Descendants	T1 and T2
Defining mutations	G709A, G1888A, A4917G, G8697A, T10463C, G13368A, G14905A, A15607G, G15928A, C16294T

In human population genetics, mitochondrial (mtDNA) haplogroups define the major lineages of direct maternal (female) lines back to a shared common ancestor in Africa. In human genetics, Haplogroup T is a predominantly Eurasian lineage.

Origins

Mitochondrial (mtDNA) Haplogroup T derives from the haplogroup J'T that also gave rise to haplogroup J. It is thought to have emanated from the Middle East (Bermisheva 2002).

Distribution

Haplogroup T is a widespread haplogroup throughout Western and Central Eurasia with varying degrees of prevalence and certainly might have been present in other groups from the surrounding areas. T is found in approximately 10% of native Europeans. It is also common among modern day Iranians. Based on a sample of over 400 modern day Iranians (Kivisild and Metspalu 2003), the T haplogroup represents roughly 8.3% of the population (about 1 out of 12 individuals), with the more specific T1 subtype constituting roughly half of those. Furthermore, the specific subtype T1 tends to be found further east and is common in Central Asian and modern Turkic populations (Lalueza-Fox 2004), who inhabit much of the same territory as the ancient Saka, Sarmatian, Andronovo, and other putative Iranian peoples of the 2nd and 1st millennia BC. Lalueza-Fox et al. (2004) also found several T and T1 sequences in ancient burials, including kurgans, in the Kazakh steppe between the 14th-10th centuries BC, as well as later into the 1st millennia BC. These coincide with the latter part of the Andronovo period and the Saka period in the region.

Haplogroup T is currently found with high concentrations around the eastern Baltic Sea.

The geographic distribution within subclade T2 varies greatly with the ratio of subhaplogroup T2e to T2b reported to vary 40-fold across examined populations from a low in Britain and Ireland, to a high in Saudi Arabia (Bedford 2012). Within subhaplogroup T2e, a very rare motif is identified among Sephardic Jews of Turkey and Bulgaria and suspected conversos from the New World (Bedford 2012). Found in Svan population from Caucasus(Georgia) T* 10,4% and T1 4,2%. T1a1a1 is particularly common in countries with high levels of Y-haplogroup R1a, such as Central and Northeast Europe, but also everywhere in Central Asia and deep into North Asia, as far east as Mongolia.

Archaeology

Wilde et al. (2014) tested mtDNA samples from the Yamna culture, the presumed homeland of Proto-Indo-European speakers, and found T2a1b in the Middle Volga region and Bulgaria, and T1a both in central Ukraine and the Middle Volga. The frequency of T1a and T2 in Yamna samples were each 14.5%, a percentage higher than in any country today and only found in similarly high frequencies among the Udmurts of the Volga-Ural region.

Africa

Haplogroup T is uncommon in Africa and is absent from most populations there. Its highest frequencies are in two Semitic speaking peoples: the Amhara and the Tigrai (Kivisild 2004).

Population	Location	Language Family	N	Frequency	Source
Amhara	Ethiopia	Afro-Asiatic > Semitic	5/120	4.17%	Kivisild 2004
Beta Israel	Ethiopia	Afro-Asiatic > Cushitic	0/29	0.00%	Behar 2008a
Dawro K.	Ethiopia	Afro-Asiatic > Omotic	2/137	1.46%	Castrì 2008 and Boattini 2013
Ethiopia	Ethiopia	Undetermined	2/77	2.60%	Soares 2011
Ethiopian Jew	Ethiopia	Afro-Asiatic > Cushitic	0/41	0.00%	Non 2011
Gurage	Ethiopia	Afro-Asiatic > Semitic	0/21	0.00%	Kivisild 2004
Hamer	Ethiopia	Afro-Asiatic > Omotic	0/11	0.00%	Castrì 2008 and Boattini 2013
Ongota	Ethiopia	Afro-Asiatic > Cushitic	0/19	0.00%	Castrì 2008 and Boattini 2013
Oromo	Ethiopia	Afro-Asiatic > Cushitic	0/33	0.00%	Kivisild 2004
Tigrai	Ethiopia	Afro-Asiatic > Semitic	3/44	6.82%	Kivisild 2004
Daasanach	Kenya	Afro-Asiatic > Cushitic	0/49	0.00%	Poloni 2009
Elmolo	Kenya	Afro-Asiatic > Cushitic	0/52	0.00%	Castrì 2008 and Boattini 2013
Kikuyu	Kenya	Niger-Congo	0/25	0.00%	Watson 1997
Luo	Kenya	Nilo-Saharan	0/49	0.00%	Castrì 2008 and Boattini 2013
Maasai	Kenya	Nilo-Saharan	0/81	0.00%	Castrì 2008 and Boattini 2013
Nairobi	Kenya	Niger-Congo	0/100	0.00%	Brandstatter 2004
Nyangatom	Kenya	Nilo-Saharan	0/112	0.00%	Poloni 2009
Rendille	Kenya	Afro-Asiatic > Cushitic	0/17	0.00%	Castrì 2008 and Boattini 2013
Samburu	Kenya	Nilo-Saharan	0/35	0.00%	Castrì 2008 and Boattini 2013
Turkana	Kenya	Nilo-Saharan	0/51	0.00%	Castrì 2008 and Boattini 2013
Turkana	Kenya	Nilo-Saharan	0/47	0.00%	Poloni 2009 and Watson 1997
Hutu	Rwanda	Niger-Congo	0/42	0.00%	Castrì 2009
Somali	Somalia	Afro-Asiatic > Cushitic	2/163	1.23%	Soares 2011 and Watson 1997
Dinka	Sudan	Nilo-Saharan	0/46	0.00%	Krings 1999
Sudan	Sudan	Undetermined	3/102	2.94%	Soares 2011
Burunge	Tanzania	Afro-Asiatic > Cushitic	0/38	0.00%	Tishkoff 2007
Datoga	Tanzania	Nilo-Saharan	1/57	1.75%	Tishkoff 2007 and Knight 2003
Iraqw	Tanzania	Afro-Asiatic > Cushitic	0/12	0.00%	Knight 2003
Sukuma	Tanzania	Niger-Congo	0/32	0.00%	Tishkoff 2007 and Knight 2003
Turu	Tanzania	Niger-Congo	0/29	0.00%	Tishkoff 2007
Yemeni	Yemen	Afro-Asiatic > Semitic	1/114	0.88%	Kivisild 2004

Subclades

Tree

This phylogenetic tree of haplogroup I subclades is based on the paper (van Oven 2008) and subsequent published research (Behar 2012b). For brevity, only the first three levels of subclades (branches) are shown.

• T
  • T1
    • T1a
      • T1a1
    • T1b
  • T2
    • T2a
      • T2a1
    • T2b
      • T2b1
      • T2b2
      • T2b3
      • T2b4
      • T2b5
      • T2b6
    • T2c
      • T2c1
    • T2d
    • T2e
      • T2e2
    • T2f
      • T2f1
    • T2g

Health Issues

One study has shown Haplogroup T to be associated with increased risk for coronary artery disease (Sanger 2007). However, some studies have also shown that people of Haplogroup T are less prone to diabetes (Chinnery 2007 and González 2012).

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

One study has found that among the Spanish population, Hypertrophic CardioMyopathy (HCM) also refereed to as Hypertrophic Obstructive CardioMyopathy or HOCM is more likely to happen in those of T2 ancestry than those in other maternal haplogroups. It is unknown whether or not this is specific to this subclaude of haplogroup T or is a risk factor shard by all of haplogroup T. With a statistically significant difference found in such a small sample, it may be advisable for those of known haplogroup T maternal ancestry to be aware of this and have their physician check for evidence of this condition whan having a routine exam at an early age. It is usually symptom-less and increases the risk of sudden cardiac death, which often happens to those of as early in life as teenagers and may affect those who are active and have no other risk factors.

Certain medical studies had shown mitochondrial Haplogroup T to be associated with reduced sperm motility in males, although these results have been challenged (Mishmar 2002). 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 (Ruiz-Pesini 2000). However, these findings have been disputed due to a small sample size in the study (Mishmar 2002).

Famous Members

Nicholas II of Russia

The last Russian Tsar, Nicholas II, has been shown to be of Haplogroup T, specifically subclade T2 (Ivanov 1996). 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. Many European royals have been found to be of this mtDNA Haplogroup, in addition to Haplogroup H (mtDNA).

See also

Genetics

3

Backbone mtDNA Tree

Evolutionary tree of human mitochondrial DNA (mtDNA) haplogroups

Mitochondrial Eve (L)

L0

L1–6

L1

L2

L3

L4

L5

L6

M

N

CZ

D

E

G

Q

O

A

S

R

I

W

X

Y

C

Z

B

F

R0

pre-JT

P

U

HV

JT

K

H

V

J

T

External links

• General
  • Ian Logan's Mitochondrial DNA Site
  • Mannis van Oven's Phylotree
  • The Genographic Project Public Participation Mitochondrial DNA Database
• Haplogroup T
  • Discussion List at RootsWeb
  • Spread of Haplogroup T, from National Geographic
  • Genetic Genealogy: A Personal Perspective on Tara, Karelians and Kent, England
  • Analysis of a Haplogroup T sequence (T5/T2)
  • Phylogenetic Networks for the Human mtDNA Haplogroup T
  • mtDNA Haplogroup T - Full Genomic Sequence Research Project
  • Phylogenetic Networks for the Human mtDNA Haplogroup T