Genetic demographic characteristics of the rural population of the Tuva Republic: Marriage structure and inbreeding

Marriage structure was studied in three rural populations of the Tuva Repub lic: the Shinaan population and the populations of Todzhinskii and Bai-Taig inskii raions (districts). The Shinaan and Bai-Taiginskii populations had h igh levels of endogamy (0.6704 and 0.6050, respectively). In the Todzhinski i population, which was characterized by a mixed ethnic composition, endoga my was 0.3779 for the total population and 0.4626 for Tuvinians; interethni c marriages in this population were rare. The values of marriage assortativ eness with respect to birthplace were 19.38, 40.75, 75.87, and 41.87% in th e Shinaan, Bai-Taiginskii, all the Todzhinskii populations, and Tuvinian mo noethnic marriages in the Todzhinskii raion, respectively. High marriage as sortativeness with respect to ethnicity was found. Its values (A(1)) were 9 1.85 and 93.49% in Tuvinians and Russians, respectively. Tuvinian populatio ns were characterized by high inbreeding. The total (F-it, random (F-st), a nd nonrandom inbreeding (F-is) estimated by isonymy were 0.004237, 0.002298 , and 0.001944 in the Shinaan population, 0.007292, 0.009448, and -0.002177 in the Bai-Taiginskii population, and 0.003846, 0.004152, and -0.000307 in the Todzhinskii population, respectively tin the latter populations, the F -it, F-st, and F-is values for Tuvinian marriages alone were 0.005000, 0.00 7222, and -0.002238, respectively). The results obtained indicate that indi vidual territorial groups of Tuvinians retain a high degree of genetic isol ation from one another.