Mother tongue: concominant replacement of language and mtdna in south caspian populations of iran

MOTHER TONGUE: CONCOMINANT REPLACEMENT OF LANGUAGE AND MtDNA IN SOUTH CASPIAN POPULATIONS OF IRAN

IVAN NASIDZE & MARK STONEKING

Comparative analysis of mtDNA and Y chromosome variation in the same groups reveals their maternal and paternal histories. Often these are the same, but sometimes there are differences in the patterns of mtDNA and Y chromosome variation, which then provide novel insights into the history of such groups. We describe here an instance in which patterns of mtDNA and Y chromosome variation differ, for the Gilaki and Mazandarani groups from the South Caspian region of Iran.

The Gilaki and Mazandarani occupy the South Caspian region of Iran and speak closely-related languages belonging to the North-Western branch of Iranian languages (Ethnologue, 2000), as do other groups in this region. Little is known about their history; it has been suggested that their ancestors came from the Caucasus region, perhaps displacing an earlier group in the south Caspian (Negahban, 2001). Linguistic evidence supports this scenario, in that the Gilaki and Mazandarani languages (but not other Iranian languages) share certain typological features with Caucasian languages (Stilo, 1981, 2005).

Here, we report the results of mtDNA and Y-chromosome analyses of the Mazandarani and Gilaki, in comparison with their geographic and linguistic neighbors (i.e., other Iranian groups) and with South Caucasian groups.

Based on mtDNA HV1 sequences, the Gilaki and Mazandarani most closely resemble their geographic and linguistic neighbors, namely other Iranian groups. However, their Y chromosome types most closely resemble those found in groups from the South Caucasus. A scenario that explains these differences is a south Caucasian origin for the ancestors of the Gilaki and Mazandarani, followed by introgression of women (but not men) from local Iranian groups, possibly because of patrilocality. Given that both mtDNA and language are maternally-transmitted, the incorporation of local Iranian women would have resulted in the concomitant replacement of the ancestral Caucasian language and mtDNA types of the Gilaki and Mazandarani with their current Iranian language and mtDNA types. Concomitant replacement of language and mtDNA may be a more general phenomenon than previously recognized.
References

Ethnologue (2000). (www.ethnologue.com).

Negahban, E.O. (2001). Gilân. In E. Yarshater (Ed.), Encyclopedia Iranica (pp. 618-634). New York: Bibliotheca Persica Press.

Stilo, D. (1981). The Tati language group in the sociolinguistic context of Northwestern Iran and Transcaucasia. Iranian Studies, 14, 137-185.