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Haplogroup K (mtDNA)

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Geographic distribution

In Europe, mtDNA K is particularly common in Northwest Europe, with peaks observed in Belgium (14%), Ireland (12%), the Netherlands (10%), Iceland (10%), Denmark (9%) and France (8.5%). In the Eastern Mediterranean and the Middle East, haplogroup K reaches high frequencies in Cyprus (20%), among the Druzes of Lebanon (13%), in Georgia (12%), as well as among the Avars (13%) and the Dargins (12%) of Daghestan.

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

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

Origins & History

Haplogroup K originated in West Asia as a subclade of haplogroup U8 sometime between 18,000 and 38,000 years ago. Based on ancient DNA tests, it appears to have been absent from Europe before the Neolithic period, and was diffused by early farmers and herders from the Near East. It was found in the remains of three individuals from the Pre-Pottery Neolithic B site of Tell Ramad, Syria, dating from circa 6000 BCE. Haplogroup K was found in approximately 15% of Neolithic samples from Europe, a frequency twice higher than among modern Europeans.

K1a is thought to have arisen around 19,000 to 22,000 years ago. It is is by far the most common and diverse subclade in Europe today, and was already by far the most common subclade among Neolithic farmers. Apart from one K2a5 sample and Ítzi's K1f, all Neolithic samples were K1a, including one K1a4a1a2. K1a is also very common in the Levant today, notably among the Druzes, who are believed to be the population most representative of the pre-Arabic expansion in the Levant, and possibly the closest to the original Neolithic farmers.The Druzes, who have 13% of haplogroup K, possess mostly K1a subclades, including K1a4b, K1a6 and K1a12. K1a4 is found in the Levant, Anatolia, Georgia, and all over Europe. K1a4a1 is the most common K subclade in Western Europe, Germany and Scandinavia today. K1a4 was probably the main K1a subclade among Neolithic farmers.

Ashkenazi Jews are the ethnic groups with the highest percentage of K lineages today : 32%, and up to 50% among Ashkenazi Jews from Germany. There are only three typically Jewish subclades of K: K1a1b1a, K1a9, and K2a2a. There are other subclades, like K1a7, K1a8 and K2c, which are also found among people of Jewish descent, but they are very rare.

Like haplogroups N1a, H2, H5, H7, H13, H20, J2b1a, T2c and X, those subclades of K are thought to have been part of the original Neolithic founder haplogroups from the Fertile Crescent, who colonised Europe accompanied by paternal lineages E1b1b, G2, J1 and T1a.

The Indo-European branches

The dominant paternal lineage in Western Europe today is R1b, which is thought to have arrived with the Indo-European speakers (Proto-Italo-Celtic and Proto-Germanic branches) during the Bronze Age (=> see R1b history). Y-haplogroup R1b is thought to have spread with cattle herders from the northern Near East and Caucasus region first to the Pontic Steppe, then to Europe. Its Near Eastern and Caucasian origin means that R1b populations almost certainly carried substantial percentages of K maternal lineages. Haplogroup K has been found in all Asian populations where R1b is present, including the Volga-Ural region, the Altai, Mongolia, Xinjiang, and most of Central Asia.

One way to determine which subclades of K were diffused by the Indo-Europeans is to look for subclades that are consistently found in all populations with high levels of haplogroup R1b in Europe, around the Caucasus, in the Near East and in Central Asia.

K1a1a is found all around Central Asia, as well as central and western Europe, and could be linked to R1b. K1c is also common in Central Asia. K1c1 is particularly common in Slavic countries, while K1c2 is more common in Germanic countries. Both could be associated with R1a. The presence of K1c2 has been confirmed in Tajikistan, a country that has 30% of R1a and only 3% of R1b.

K2b was found by Keyser et al. (2009) in Bronze Age samples related to the Andronovo culture from the Krasnoyarsk area in southern Siberia. The male samples tested from the same site belonged R1a. Nowadays K2b is found mostly in central and north-eastern Europe (R1a countries) and can therefore safely be linked to the diffusion of the R1a branch of the Indo-Europeans.

Data for deep subclades outside Europe is still sparse, but other potential candidates include K1a3 and K2a6. Note that K1a4 was also found among Neolithic farmers in Germany, but since most K1a subclades originated in the Near East it should not be surprising to find overlaps between Neolithic farmers and Bronze Age Indo-European invaders. It is also the most common subclade in Northwest Europe.

Subclades

  • K1
    • K1a
      • K1a1 : found in central and south-eastern Europe/li>
        • K1a1a : found in central, northern and western Europe
        • K1a1b
          • K1a1b1 : found in western Europe
            • K1a1b1a : major Ashkenazi Jewish subclade
            • K1a1b1b : found in Scandinavia and Britain
            • K1a1b1c : found in north-western Europe
            • K1a1b1d : found in Britain
            • K1a1b1e : found in western Europe
            • K1a1b1f : found in north-western Europe
            • K1a1b1g : found in Greece
          • K1a1b2
            • K1a1b2a : found in north-western Europe
            • K1a1b2b : found in Britain
        • K1a1c : found in north-western Europe
      • K1a2: found in northern Europe and Iran (Qashqai)
        • K1a2a : found in north-western Europe
        • K1a2b : found around Germany
        • K1a2c : found in northern Europe
      • K1a3
        • K1a3a : found in Russia, central and western Europe
      • K1a4
        • K1a4a : found in central and south-eastern Europe
          • K1a4a1 : found in western, central, northern and eastern Europe, as well as in Ethiopia (Hamar)
        • K1a4b : found in the Levant (Druzes)
        • K1a4c : found in Iran, Anatolia, Greece, Italy and Britain
        • K1a4d : found around Germany, France and the Low Countries
        • K1a4e
        • K1a4f : found in northern Anatolia
      • K1a5 : found in the Levant
      • K1a6 : found in the Levant (Druzes)
      • K1a7 : found among Ashkenazi Jews
      • K1a8 : found among Ashkenazi Jews
        • K1a8a : found among Ashkenazi Jews
        • K1a8b : found in Tunisia and Iran
      • K1a9 : major Ashkenazi Jewish subclade
      • K1a10
        • K1a10a : found in the British Isles and Scandinavia
      • K1a11 : found in north-western Europe and around Germany
        • K1a11a : found in Germany
        • K1a11b
      • K1a12 : found in Germany and Italy
        • K1a12a : found in the Levant (Jews, Druzes), Turkey and Ethiopia
      • K1a13
        • K1a13a : found in Croatia and Spain
      • K1a14 : found in the Azores
      • K1a15 : found in Scotland and Ireland
      • K1a16 : found in Scotland
      • K1a17 : found in the Near East (Turkey, Levant, Egypt)
        • K1a17a
      • K1a18 : found in the Near East (Levant, Mesopotamia)
      • K1a19 : found in Iran, Italy and Poland
      • K1a20 : found in Turkey and Georgia
      • K1a21 : found in Germany and Italy
      • K1a23 : found in the Levant
      • K1a24 : found in north-western Europe
        • K1a24a : found in Ireland
      • K1a25
      • K1a26 : found in the British Isles
      • K1a27 : found in the Levant
    • K1b
      • K1b1
        • K1b1a : found throughout Europe
        • K1b1b : found in Greece
        • K1b1c : found in central Europe and Iran (Kurds, Qashqai)
      • K1b2
        • K1b2a : found in central and northern Europe
        • K1b2b : found in western continental Europe
    • K1c
      • K1c1
        • K1c1a : found in Italy
        • K1c1b : found in northern Europe
        • K1c1c : found in Finland and European Russia
        • K1c1d : found in Germany
        • K1c1e : found in the Carpathians and Russia
        • K1c1f : found in central Europe
      • K1c2 : found in western and northern Europe and in the Maghreb
        • K1c2a : found in Ireland
    • K1d : found in northern Europe
    • K1e : found in north-western Europe
    • K1f : found in Ítzi (the Tyrolean Iceman)
  • K2
    • K2a
      • K2a1 : found in Britain
      • K2a2 : major Ashkenazi Jewish subclade
      • K2a3 : found in northern and eastern Europe
      • K2a4 : found in northern Europe
      • K2a5 : found in north-western Europe and Iran (Persians)
      • K2a6 : found in the North Caucasus, central and north-western Europe
      • K2a7 : found in France and Britain
      • K2a8 : found in Spain and the Canaries
      • K2a9
      • K2a10 : found in north-western Europe
    • K2b
      • K2b1 : found in central and northern Europe
      • K2b2 : found in central and northern Europe
    • K2c : found among Ashkenazi Jews
  • K3 : found in Georgia

Associated medical conditions

Coskun et al. (2004) studied the mutations that suppress mitochondrial transcription and replication and reported that haplogroup K could be protective against Alzheimer's Disease (AD).

The A10398G mutation defining haplogroup K1 (a back mutation from macrohaplogroup N) has been associated with increased longevity (Nijiati et al. (2013)) and protection against PD (Ghezzi et al. (2005) and Clark et al. (2011)). This mutation is also found in the K2a11 subclades.

The common C150T mutation has been found at strikingly higher frequency among Chinese and Italian centenarians and may be advantageous for longevity and resistance to stress according to Chen et al. (2012). C150T defines haplogroups K1a11, K1a24, K1a30 and K3, but may also be found among other subclades.

Rollins et al. (2009) examined the association between brain pH and mtDNA alleles. The highest brain pH was found in members of haplogroups U and K. The A10398G polymorphism (defining hg I, J and K1) was found to be associated with an increased pH in cybrid cells. Higher pH confers protection against Parkinson's disease and psychiatric disorders such as schizophrenia, bipolar disorder, and major depressive disorder. Another study by the University of Manchester suggests that a lower brain acidity (i.e. higher pH) has a protective effect against strokes.

Research on intelligence point that people with higher IQ tend to have more alkaline brains. Higher pH is associated with better conductivity-transmission between neurons (source).

Hendrickson et al. (2008) studied the role played by mitochondrial function in AIDS progression in HIV-1 infected persons. They found that AIDS progression was slower for members of haplogroups H3, I, K, U, W and X.

Famous individuals

Ítzi the Iceman, Europe's oldest natural human mummy, dating from 5,300 years ago, had his full genome sequenced (the oldest European genome ever tested) and was found to belong to haplogroup K1f.

Other famous members of haplogroup K

  • Craig Venter (subclade K1a3a): an American biologist and entrepreneur, who was one of the first to sequence the human genome. He also created the first cell with a synthetic genome He was listed on Time magazine's 2007 and 2008 Time 100 list of the most influential people in the world.
  • Steven Pinker (subclade K2a2a): a Canadian experimental psychologist, cognitive scientist, linguist, and popular science author.
  • Mike Nichols (subclade K2a2a): a German-born American television, stage and film director, writer, producer and comedian. He is one of a small group of people who have won an Emmy, Grammy, Oscar, and Tony Award.
  • Meryl Streep: an American actress of theater, television, and film. She is widely regarded as one of the greatest film actresses of all time.
  • Stephen Colbert: an American political satirist, writer, comedian, television host, and actor. He is the host of Comedy Central's The Colbert Report, a satirical news show in which Colbert portrays a caricatured version of conservative political pundits.
  • Katie Couric: an American television journalist, author and talk show host. She has been a television host on all Big Three television networks in the United States (ABC, CBS and NBC) as well as the global news anchor for Yahoo News.

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