[Relation between heterozygosity and fertility in Forest Nentzy and Nganasan tribes]. / Izuchenie sviazi geterozigotnosti s parametrami plodovitosti u lesnykh nentsev i nganasan.

The relationship between heterozygosity for 13 polymorphic loci and fertility of women having passed the menopause was studied in two North-Siberian tribes: Forest Nentzy (N = 108) and Nganasans (N = 68). The number of pregnancies positively correlated with the individual heterozygosity (r = 0.2910 +/- 0.1063; P less than 0.01) in Forest Nentzy, while in Nganasans this correlation was absent. Women with the average level of individual heterozygosity were characterized by minimal values of variation in pregnancies' number and maximal Q index of realized fertility. It is concluded that the average level of individual heterozygosity is optimal for both tribes.

[Consanguineous marriages, inbreeding and its effects in the Taimyr Nganasans]. / Rodstvennye braki, inbriding i ego éffekty u nganasan Taimyra.

Genealogy, marriage structure, inbreeding and its effects in Taimyr Nganasans have been studied in detail. The population size in 715. 223 pairs were analysed. Uncle-niece and first cousin marriages were absent. Marriage frequency of second cousins and more remote relatives is 20.0%. Average inbreeding coefficient of the population is 0.0022 with some variation among three subpopulations (0.0015-0.0027). Consanguineous marriages are characterized by lower average number of livebirths, living children, stillbirths and miscarriages. There are some difficulties in the interpretation of the differences received because of a higher incidence of repeated marriages between relatives; 6 cases of hereditary diseases were registered among the offsprings of nonconsanguineous marriages, including two cases with one parent inbred.

[Genetic structure of an isolated group of the indigenous population of northern Siberia, the Nganasans (Tavginians) of Taimir]. / Geneticheskaia struktura obosoblennoi gruppy korennogo naseleniia severnoi Sibiri--nganasan (tavgii tsev) Taimira.

Demographic data of genetic interest were studied in presently living population in comparison with preseding generations of Nganasans. Decrease of sex ratio in the whole population has been revealed along with the reduction of reproductive and, possibly, effective size. The number and variance of livebirths per female were 7.29 and 9.86 respectively. Crow' index of the opportunity for selection (I) and its components (Im and If) were estimated. I was found to be 1.17, whereas Im and If--1.56 and 0.18 respectively. Linear pattern of settling in the past as well as the type of migration between adjoining subpopulations depended on culture and economy of arctic reindeer hunters as well as landscape character.

[Genetic structure of an isolated group of the indigenous population of northern Siberia--Nganasans (Tavgiitsi) of Taymyr. I. History, erythrocyte and serum blood systems, isoenzymes]. / Geneticheskaia struktura obosoblennoi gruppy korennogo naseleniia Severnoi Sibiri--nganasan (tavgiitsev) Taimyra. Soobshchenie I. Istoriia formirovaniia, éritrotsitarnye i syvorotochnye sistemy krovi, izofermenty.

Nganasans is a small samodyen-speaking ethnic group originated from several clans of reindeer hunters. Pedigree studies revealed no consanguineous matings of uncle-niece, aunt-nephew, first cousins type among 120 families studied. Rather rarely mating between second cousins could be observed. The reviewed traditional kindship system based on bilateral exogamy is an explanation. Data on 12 blood systems and 6 red cell enzymes distribution in two main localities almost totally studied have been presented. No A2, r, K, MS alleles were observed. Hgh frequencies of Ns, R2, Fya, Jka, Gm1 have been found. Diegoa was seen in only one family. Polymorphism on PGM1, 6-PGD, AK and AP, monomorphism on LDH and MDH has been observed.