Haplogroup L-M20

In, Haplogroup L (M20) is a.

This haplogroup is associated with. It has also been found at low frequencies among populations of, , and along the coast of the. It is a descendant haplogroup of, and is believed to have first appeared approximately 30,000 years ago.

Haplogroup L is currently present in the Indian population at an overall frequency of ca. 7-15% (Basu et al. 2003, Cordaux et al. 2004, Sengupta et al. 2006, Thamseem et al. 2006). It is especially frequent among upper and middle castes (ca. 17-19%), but is somewhat rarer in  upper and middle castes (ca. 5-6%), which suggests that it may have been (perhaps besides J2) the original Y-haplogroup of the creators of the  (Sengupta et al. 2006). Its highest frequency and diversity can be found in western Pakistan/Baluchistan (28%), from where the agricultural creators of this civilization colonized the Indus valley in the 4th millennium BC (Qamar et al. 2002). The presence of haplogroup L is quite rare among tribal groups (ca. 5,6-7%) (Cordaux et al. 2004, Sengupta et al. 2006, Thamseem et al. 2006), which indicates that it was not a Y-haplogroup of the original Paleolithic population of India.

Haplogroup L and : According to DNA testing, are remarkable for their high frequency (35%) of males who carry the   (M295), which is present in only about 6.4% of the general  population of the Middle East.

Early reports (e.g. Wells et al. 2001) of a very high frequency (approaching 50%) of Haplogroup L in South India appear to have been due to extrapolation from data obtained from a sample of 84, a -speaking warrior caste of , among whom 40 (approx. 48%) displayed the M20 mutation that defines Haplogroup L. Subsequent studies of various Indian populations have shown this high frequency of Haplogroup L among the Kallars to be an anomaly in the region; Haplogroup L Y-chromosomes rarely comprise even 25% of the Y-chromosome diversity among any Indian population.

Sengupta et al. (2006) recently discovered three subbranches of haplogroup L: L1 (M76), L2 (M317), and L3 (M357). All three are present in Iran and Pakistan, but only L1 is regularly found in India. They make a case for an indigenous origin of L1 in India, by arguing that the spatial distributions of both L1 HG frequency and associated microsatellite variance show a pattern of spread emanating from southern India. By linking haplogroup L1 to the Dravidian speakers, they simultaneously argue for an Indian origin of Dravidian languages. Unfortunately, there seems to be little interest in the origin and distribution of this haplogroup outside India.

An article by O. Semino et al. published in the journal Science (Volume 290, ) 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, , , , , , and. The sizes of the samples analyzed in this study were generally quite small, so it is possible that the actual frequency of Haplogroup L 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 in Southwest Asia and Europe. 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 might belong to the L2 (M317), which is, among South Asian populations, generally the rarest of the subclades of Haplogroup L.

Subgroups
The s of Haplogroup L with their defining mutation(s), according to the 2006 ISOGG tree:


 * L (M11, M20, M22, M61, M185, M295) Typical of populations of 
 * L*
 * L1 (M27, M76) Typical of castes of  and, with a moderate distribution among  populations of 
 * L2 (M317) Found at low frequency in, , and 
 * L2*
 * L2a (M274)
 * L2b (M349)
 * L3 (M357) Found frequently among and, with a moderate distribution among the general  population
 * L3*
 * L3a (PK3) Found among