Human Y chromosome DNA grouping common in South Asia and the Mediterranean
Haplogroup L-M20 is a human Y-DNA haplogroup, which is defined by SNPs M11, M20, M61 and M185. As a secondary descendant of haplogroup K and a primary branch of haplogroup LT, haplogroup L currently has the alternative phylogenetic name of K1a, and is a sibling of haplogroup T (a.k.a. K1b).
The presence of L-M20 has been observed at varying levels throughout South Asia, peaking in populations native to the southern Pakistani province of Balochistan (28%), Northern Afghanistan (25%), and Southern India (19%). The clade also occurs in Tajikistan and Anatolia, as well as at lower frequencies in Iran. It has also been present for millennia at very low levels in the Caucasus, Europe and Central Asia. The subclade L2 (L-L595) has been found in Europe and Western Asia, but is extremely rare.
Phylogenetic tree.
There are several confirmed and proposed phylogenetic trees available for haplogroup L-M20. The scientifically accepted one is the Y-Chromosome Consortium (YCC) one published in Karafet 2008 and subsequently updated. A draft tree that shows emerging science is provided by Thomas Krahn at the Genomic Research Center in Houston, Texas. The International Society of Genetic Genealogy (ISOGG) also provides an amateur tree.
This is Thomas Krahn at the Genomic Research Center's Draft tree Proposed Tree for haplogroup L-M20:
Origins.
L-M20 is a descendant of Haplogroup LT, which is a descendant of haplogroup K-M9. According to Dr. Spencer Wells, L-M20 originated in the Eurasian K-M9 clan that migrated eastwards from the Middle East, and later southwards from the Pamir Knot into present-day Pakistan and India. These people arrived in the Indian subcontinent approximately 30,000 years ago. Hence, it is hypothesized that the first bearer of M20 marker was born either in the subcontinent or the Middle East. Other studies have proposed either a West Asian or South Asian origin for L-M20 and associated its expansion in the Indus valley to Neolithic farmers. Genetic studies suggest that L-M20 may be one of the haplogroups of the original creators of the Indus Valley Civilisation. Time estimates generated based on seven Y-STR loci within L-M20 lineages for north (14.6±7.3 kya) and south (17.8±8.4 kya) Afghanistan populations are intermediate to those of Pakistan (26.3±5.3 kya) and India (7.5±1.7 kya). Furthermore, Pakistan displays higher haplotype variance (0.548) than India (0.118), suggesting that L-M20 most likely originated in what is today Pakistan then subsequently spread into southern India.
McElreavy and Quintana-Murci, writing on the Indus Valley Civilisation, state that
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Sengupta et al. (2006) observed three subbranches of haplogroup L: L1-M76 (L1a1), L2-M317 (L1b) and L3-M357 (L1a2), with distinctive geographic affiliations. Almost all Indian members of haplogroup L are L1 derived, with L3-M357 occurring only sporadically (0.4%). Conversely in Pakistan, L3-M357 subclade account for 86% of L-M20 chromosomes and reaches an intermediate frequency of 6.8%, overall. L1-M76 occurs at a frequency of 7.5% in India and 5.1% in Pakistan, exhibiting peak variance distribution in the Maharashtra region in coastal western India.
Geographical distribution.
In India, L-M20 has a higher frequency among Dravidian castes, but is somewhat rarer in Indo-Aryan castes. In Pakistan, it has a frequency of about 28% in the southern regions including southern Baluchistan, from where the agricultural creators of the Indus valley civilization emerged .
Preliminary evidence gleaned from non-scientific sources, such as individuals who have had their Y-chromosomes tested by commercial labs, suggests that most European examples of Haplogroup L-M20 might belong to the subclade L2-M317, which is, among South Asian populations, generally the rarest of the subclades of Haplogroup L.
South Asia.
India.
It has higher frequency among Dravidian castes (ca. 17-19%) but is somewhat rarer in Indo-Aryan castes (ca. 5-6%). The presence of haplogroup L-M20 is quite rare among tribal groups (ca. 5,6-7%).( However, the Korova tribe of Uttara Kannada in which L-M11 occurs at 68% is an exception.
L2a2 is around 62.7% among Brokpa of Ladakh. L-M20 was found at 38% in the Bharwad caste and 21% in Charan caste from Junagarh district in Gujarat. It has also been reported at 17% in the Kare Vokkal tribe from Uttara Kannada in Karnataka. It is also found at low frequencies in other populations from Junagarh district and Uttara Kannada. L-M20 is the single largest male lineage (36.8%) among the Jat people of Northern India and is found at 16.33% among the Gujar's of Jammu and Kashmir. It also occurs at 18.6% among the Konkanastha Brahmins of the Konkan region and at 15% among the Maratha's of Maharashtra. L-M20 is also found at 32.35% in the Vokkaligas and at 17.82% in the Lingayats of Karnataka.
And available data shows that among Tamils, L-M20 is found at 48% among Kallar, 20.56% among Tamil yadavas, 28.57% among Vanniyars, 28.81% among Nadar, and 26% among the Saurashtra people, 20.7% among the Ambalakarar, 16.7% among the Iyengar and 17.2% among the Iyer castes of Tamil Nadu. L-M11 is found in frequencies of 8-16% among Indian Jews. L-M20 has an overall frequency of 12% in Punjab. 2% of Siddis have also been reported with L-M11. Haplogroup L-M20 is currently present in the Indian population at an overall frequency of ca. 7-15%.
Pakistan.
The greatest concentration of Haplogroup L-M20 is along the Indus River in Pakistan where the Indus Valley civilization flourished during 3300–1300 BC with its mature period between 2600 and 1900 BCE. L-M357's highest frequency and diversity is found in the Balochistan province at 28% with a moderate distribution among the general Pakistani population at 11.6%. It is also found in Afghanistan ethnic counterparts as well, such as with the Pashtuns and Balochis. L-M357 is found frequently among Burusho (approx. 12%) and Pashtuns (approx. 7%),
L1a and L1c-M357 are found at 24% among Balochis, L1a and L1c are found at 8% among the Dravidian-speaking Brahui, L1c is found at 25% among Kalash, L1c is found at 15% among Burusho, L1a-M76 and L1b-M317 are found at 2% among the Makranis and L1c is found at 3.6% of Sindhis according to Julie di Cristofaro et al. 2013. L-M20 is found at 17.78% among the Parsis. L3a is found at 23% among the Nuristanis in both Pakistan and Afghanistan.
L-PK3 is found in approximately 23% of Kalash in northwest Pakistan.
In one study, the haplogroup L was found also observed among the Gujars at a frequency of (20.97%) in northwest Pakistan.
Middle East and Anatolia.
L-M20 was found in 51% of Syrians from Raqqa, a northern Syrian city whose previous inhabitants were wiped out by Mongol genocides and repopulated in recent times by local Bedouin populations and Chechen war refugees from Russia . In a small sample of Israeli Druze haplogroup L-M20 was found in 7 out of 20 (35%). However, studies done on bigger samples showed that L-M20 averages 5% in Israeli Druze, 8% in Lebanese Druze, and it was not found in a sample of 59 Syrian Druze. Haplogroup L-M20 has been found in 2.0% (1/50) to 5.25% (48/914) of Lebanese .
Central Asia.
Afghanistan.
A study on the Pashtun male lineages in Afghanistan, found that Haplogroup L-M20, with an overall frequency of 9.5%, is the second most abundant male lineage among them. It exhibits substantial disparity in its distribution on either side of the Hindu Kush range, with 25% of the northern Afghan Pashtuns belonging to this lineage, compared with only 4.8% of males from the south. Specifically, paragroup L3*-M357 accounts for the majority of the L-M20 chromosomes among Afghan Pashtuns in both the north (20.5%) and south (4.1%). An earlier study involving a lesser number of samples had reported that L1c comprises 12.24% of the Afghan Pashtun male lineages. L1c is also found at 7.69% among the Balochs of Afghanistan. However L1a-M76 occurs in a much more higher frequency among the Balochs (20 to 61.54%), and is found at lower levels in Kyrgyz, Tajik, Uzbek and Turkmen populations.
East Asia.
Researchers studying samples of Y-DNA from populations of East Asia have rarely tested their samples for any of the mutations that define Haplogroup L. However, mutations for Haplogroup L have been tested and detected in samples of Balinese (13/641 = 2.0% L-M20), Han Chinese (1/57 = 1.8%), Dolgans from Sakha and Taymyr (1/67 = 1.5% L-M20) and Koreans (3/506 = 0.6% L-M20).
Europe.
An article by O. Semino "et al." published in the journal "Science" (Volume 290, 10 November 2000) reported the detection of the M11-G mutation, which is one of the mutations that defines Haplogroup L, in approximately 1% to 3% of samples from Georgia, Greece, Hungary, Calabria (Italy), and Andalusia (Spain). The sizes of the samples analyzed in this study were generally quite small, so it is possible that the actual frequency of Haplogroup L-M20 among Mediterranean European populations may be slightly lower or higher than that reported by Semino "et al.", but there seems to be no study to date that has described more precisely the distribution of Haplogroup L-M20 in Southwest Asia and Europe.
Southern Africa and the Swahili Coast.
Researchers in 2013 studying the origins of the Lemba people - who are of paternal South Arabian ancestry - found that 13.8% of Lemba males carried the Y-DNA L-M20, specifically the subclade L-M349 making it the 4th most common lineage amongst them. A Lemba sample from South Africa submitted to Familytreedna in 2023 was found to carry a yet unnamed L-M349 subclade of L-FT408126 which was closest to 2 samples from Iraq and Iran.
Researchers also found traces of traces of L-M20 on the Swahili coast in Kenya amounting to 4.2% of the total population.
Subclade distribution.
L1 (M295).
L-M295 is found from Western Europe to South Asia.
The L1 subclade is also found at low frequencies on the Comoros Islands.
L1a1 (M27).
L-M27 is found in 14.5% of Indians and 15% of Sri Lankans, with a moderate distribution in other populations of Pakistan, southern Iran and Europe, but slightly higher Middle East Arab populations. There is a very minor presence among Siddi's (2%), as well.
L1a2 (M357).
L-M357 is found frequently among Burushos, Kalashas, Brokpa, Jats, Pashtuns, with a moderate distribution among other populations in Pakistan, Georgia, Chechens, Ingushes, northern Iran, India, the UAE, and Saudi Arabia. Brokpa of Ladakh carry Y haplogroup L2a2 around 62.7% according to generetic study of 2019.
A Chinese study published in 2018 found L-M357/L1307 in 7.8% (5/64) of a sample of Loplik Uyghurs from Qarchugha Village, Lopnur County, Xinjiang.
L-PK3, which is downstream of L-M357, is found frequently among Kalash.
L1b (M317).
L-M317 is found at low frequency in Central Asia, Southwest Asia, and Europe.
In Europe, L-M317 has been found in Northeast Italians (3/67 = 4.5%) and Greeks (1/92 = 1.1%).
In Caucasia, L-M317 has been found in Mountain Jews (2/10 = 20%), Avars (4/42 = 9.5%, 3%), Balkarians (2/38 = 5.3%), Abkhaz (8/162 = 4.9%, 2/58 = 3.4%), Chamalals (1/27 = 3.7%), Abazins (2/88 = 2.3%), Adyghes (3/154 = 1.9%), Chechens (3/165 = 1.8%), Armenians (1/57 = 1.8%), Lezgins (1/81 = 1.2%), and Ossetes (1/132 = 0.76% North Ossetians, 2/230 = 0.9% Iron).
L-M317 has been found in Makranis (2/20 = 10%) in Pakistan, Iranians (3/186 = 1.6%), Pashtuns in Afghanistan
(1/87 = 1.1%), and Uzbeks in Afghanistan (1/127 = 0.79%).
L1b1 (M349).
L-M349 is found in some Crimean Karaites who are Levites. Some of L-M349's branches are found in West Asia, including L-Y31183 in Lebanon, L-Y31184 in Armenia, and L-Y130640 in Iraq, Iran, Yemen and South Africa. Others are found in Europe, such as L-PAGE116 in Italy, L-FT304386 in Slovenia, and L-FGC36841 in Moldova. 13.8% of Lemba males carry L-M349 under the clade L-Y130640. This percentage is most likely due to a founder effect in their population making them the only group on the African continent with any substantial proportion of L-M20.
L2 (L595).
L2-L595 is extremely rare, and has been identified by private testing in individuals from Europe and Western Asia.
Two confirmed L2-L595 individuals from Iran were reported in a 2020 study supplementary. Possible but unconfirmed cases of L2 include 4% (1/25) L-M11(xM76, M27, M317, M357) in a sample of Iranians in Kordestan and 2% (2/100) L-M20(xM27, M317, M357) in a sample of Shapsugs, among other rare reported cases of L which don't fall into the common branches.
Nomenclature.
Prior to 2002, there were in academic literature at least seven naming systems for the Y-Chromosome Phylogenetic tree. This led to considerable confusion. In 2002, the major research groups came together and formed the Y-Chromosome Consortium (YCC). They published a joint paper that created a single new tree that all agreed to use. Later, a group of citizen scientists with an interest in population genetics and genetic genealogy formed a working