Genetic demographic characteristics of the rural population of the Tuva Republic: Ethnic and tribal composition and sex and age structure

The ethnic, tribal, sex, and age composition was studied in populations of three districts of the Tuva Republic that were remote from one another. The se were the Kyzylskii (the Shinaan population), Todzhinskii, and Bai-Taigin skii raions. The Todzhinskii population was characterized by a mixed ethnic composition dominated by Tuvinians and Russians (62.35 and 35.52%, respect ively); the other two districts were only inhabited by Tuvinians. The studi ed populations differed from one another in the set and proportions of trib al groups-in the Todzhinskii raion, Turkic tribal groups were prevalent, wh ereas in the Shinaan and Bai-Taiginskii populations, many tribal groups of Mongolian origin were found. The estimations of relationship by isonymy ind icated a considerable contribution of geographic isolation to the genetic d ifferentiation of the populations: the estimated relationship between the h ighland Shinaan and Todzhinskii populations, which are difficult of access, was the minimum (R-i = 0.00262); the coefficients of the relationship by i sonymy between the Shinaan and Bai-Taiginskii populations and between the T odzhinskii and Bai-Taiginskii populations were 0.00336 and 0.00483, respect ively. All the studied populations were characterized by a "growing" age py ramid; however, the Bai-Taiginskii and Todzhinskii populations showed a ten dency to narrowing its base,In addition, these two populations exhibited an unfavorable sex ratio at the reproductive age, The obtained results sugges t that the Tuva population is genetically heterogeneous, which is accounted for by the tribal characteristics, the history of populations, and the geo graphic characteristics of the region.