Abstract: A Survey on the eonsanguineous marriages in five ethnic groups in Yili Kazakh Autonomous Region was earried out from April, 1983 to May, 1984. The total number of marriages inquired was: Uygur-—2553, Kazakh—1079, Hui—1235, Xibe-——1222 and Mongol——446. The percentage of consanguineous marriage and average inbreeding coefficient observed were: Uygur-8. 23% and 46. 74×10-4, Hui-—8. 10% and 45. 07 × 10-4, Xibe — 4. 66% and 24. 93 × 10-4, Kazakh —- 2. 87% and 11. 31 × 10-3, Mongol — 0. 45% and 2. 80 × 10-4, respeetively. It was noted that after 1950 the percentage of consanguineous marriage decreased in Xibe, but increased in Uygur and Hui. Most of the consanguineous marriages take place between the first cousins on maternal side, but 26. 18% of consanguineous marriage in Uygur and 14. 00% in Hui were between relatives on the paternal side. The percentage of mixed marriages in five ethnic groups ranged from 0. 2% to 4. 0%. In addition, the mortality before the age of 7 years (12. 89%) and the rate of congenital abnomalities and diseases 2. 99%) among children of consanguineous narriages were significantly higher than those of marriages between nonrelative (7. 76% and 0. 38%, respectively) .

Key words: Consanguineous marriage; Inbreeding coefficient; Mixed marriage