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Thursday, November 30, 2006

Haplogroup R2

At the moment, one of the least common y-chromosome haplogroups in the Italy DNA Project is haplogroup R2.

This haplogroup has been in the spotlight a little bit recently, due to a paper by Sengupta et al. (2006) entitled Polarity and Temporality of High Resolution Y-chromosome Distributions in India Identify Both Indigenous and Exogenous Expansions and Reveal Minor Genetic Influence of Central Asian Pastoralists. Sengupta proposes an Indian origin for haplogroup R2 (along with F* and L1). R2 is found with high frequency throughout South Asia and with diminishing frequency to the west.

Haplogroup R2 is exceedingly rare in Europe, with one notable exception: the Sinte or Sinti. The Sinti are a historically nomadic people, often considered to be a subgroup of the Roma. It is estimated that there are 120,00 to 150,2000 Roma, Sinti, and Caminanti people in Italy. The Sinti populations tend to be genetic isolates, and R2 frequencies as high as 53% have been observed among them.

Recently, an outbreak of measles was found to be clustered among Roma and Sinti Italian populations.

R2 is also found among non-Roma Indian populations, of course, as well as Central Asians (Pakistanis, Kurds, Caucasians, etc) so there are several possible paths that R2 could have taken on its way to Italy.

Our project also has two members in haplogroup L, which is also found in India but is almost never observed among the Sinti or the Roma.


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