Haplogroup T (mtDNA)

Haplogroup T is a human mitochondrial DNA (mtDNA) haplogroup. Haplogroup T derives from the haplogroup JT, which also gave rise to Haplogroup J. Haplogroup T is believed to have originated in Mesopotamia approximately 10,000 years before present, and to have moved northwards. It is found with particularly high concentrations around the eastern Baltic Sea.

In his popular book The Seven Daughters of Eve, Bryan Sykes (who is himself in haplogroup T) named the originator of this mtDNA haplogroup Tara.

Studies, which have since been proven wrong, had shown mitochondrial haplogroup T to be associated with reduced sperm motility in males. Such studies were not studies on fertility, and reduced fertility needn't be inferred from such results.

People of haplogroup T
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. As a consequence, all his matrilineal relatives have haplotype T. 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 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 the subgroup T2.