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U3 mtDNA Haplogroup

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mtDNA haplogroup U3 is present in low percentages throughout Europe and Western Asia. It is an ancient haplogroup arising over 30,000 year ago from the very old haplogroup U. It rises to its greatest frequencies in the Near East and Southern Caucasus, that is the mountainous area of Western Iran, Georgia, Armenia, Azerbaijan, Turkey, Syria, Jordan and Iraq, where the percentages vary between 4 and 8 percent. Currently U3 can be divided into three subclades, U3a, U3b and U3c. The latter is a subclade of the original U3ac and split off from U3a 1000's of years ago. All three subclades occur in the above mentioned areas with the exception of Turkey and Armenia, where U3c appears to be absent and U3a is very rare, those countries being dominated by U3b.

In Europe U3 is still common in Bulgaria and the eastern most islands of the Mediterranean Sea, Cyprus, Rhodes, Crete, where percentages rise to 3 or 4 percent, but becomes rarer and rarer as one moves west with one exception. Again Bulgaria, the Greek mainland and Etruscan Italy are dominated by U3b, whereas the Mediterranean Islands and the rest of Italy have all three subclades.

The one exception is one sub-branch of subclade U3a called U3a1 which appears to have originated in Europe. At least at this point no instance of this clade has been observed in the Mid-East. This sub-branch dominates U3 in Western Europe especially along the Atlantic coast making up over 60% of U3 in these areas with frequencies rising to as high as 1% of the total population in Scotland and Wales and as high as 3 or 4% in Iceland. Also well over half of this sub-subclade is made up of one version of U3a1 called U3a1c, with a change at 16356, and which accounts for most of the distribution along the coastline from Norway to Northern Portugal.

U3 also occurs along the North African coast which borders the Mediterranean. The subclade U3b dominates the eastern countries including Egypt and Ethiopia, whereas both U3a (in its older form found in the Near East) and U3b occur in the Berber occupied areas from Libya through Morocco, where again the percentage rises to as high as 1% of the total population.

There are isolated pockets in the Near East where U3 occurs at a very high percentage of the population; U3 makes up 16% of the Adegei in the Northern Caucasus, about 18% of Iraqi Jews around Baghdad, 39% of Jordaneans of the Dead Sea Valley, 11% of the Qashqai in Southwest Iran (note these people speak a dialect closely related to Azerbaijani of the Caucasus) 17% in one study of Luri in the Western Zagros, 12% on the Greek island of Rhodes and also among the Romani (Gypsies) of Poland, Lithuania and Spain where percentages vary from nearly 40% to as high as 55%.

Most of these groups show little variance with one or two sub-haplotypes dominating and appear to be due to founder effects and genetic drift in a small population. This is especially true of the Adegei and the Romani. Again the one exception is the Western Iranian mountains (Zagros) where both the Luri and the Qashqai show not only high percentages but also a high degree of variance including both U3a and U3b with U3c occurring nearby.

All members of haplogroup U3 are expected to have the basic characteristics of U plus four differences that define U3. Customers of FTDNA can expect that they will have been tested for a coding region SNP (likely 12308G) before being assigned to haplogroup U or any of its subclades. Additionally, any customer in haplogroup U who has HVR2 results should observe that they have at least the following: 073G, 263G, and 315.1C. From there, you will be assigned to a subclade of haplogroup U based on your HVR1 test results. Every member of U3 should expect to observe 16343G - sometimes abbreviated to simply "343G", since this is one of the four defining markers of haplogroup U3. A second one is 150T, which is in HVR2. The remaining two (14139G and 15454C) are in the coding region and would only be revealed with the purchase of a full genomic sequence.

Although the distinction is largely made in the coding region, the subclades U3a, U3b and U3c can usually be distinguished in the HVR1 Region. U3a can almost always be recognised by the presence of 16390A (or simply "390A"). And U3c can almost always be recognised by the presence of 16193T and 16249C. Whereas U3b will have neither of these patterns. The common European subclade U3a1 can only be determined through a full test including the coding region, although U3a1c along the Atlantic coast can usually be recognised by a change at 16356C along with 16390A. Sometimes U3a1c will still be erroneously labeled as U4 by FTDNA and in some early studies, as 16356C is the defining marker of U4, but U3a1c can be distinguished from U4 by the presence of 16343G along with 16356C.

It is interesting that wherever U3 can be observed both U3a and U3b is also generally observed in the same area although as pointed out above the ratios vary considerably. U3 can be observed as far east as Western Siberia and Southeast into Pakistan, Afghanistan and Northern India but in very low frequencies. U3c, an older version of U3ac, covers quite a surprising wide area given its extreme rarity. It can be observed from South of the Caspian Sea all the way over through the Mediterranean countries to the West Coast of Europe including Scotland. Currently it is believed that U3 entered Europe for the first time during the Neolithic movement of peoples 8 or 9 thousand years ago probably mainly through the Eastern Mediterranean but also up the Danube Valley from the Black sea. It appears to have been embedded within the larger population located somewhere in the mountainous areas surrounding the Levant from before 30,000 ybp and when these populations began to increase and spread about 18 or 20 thousand years ago there was left from the constant appearance of new clades and the going extinct of those already existing only 2 versions of U3: U3b and U3ac, which had been diverging from each other for 1000's of years. Until we have much more data from the Mid-East it will be difficult to pin down more precisely the origin of this haplogroup.