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This paper analyzes 2052 marriage records for 1990-2000 in the Khabezsky district of Karachay-Cherkessia. The main marriage and migration characteristics of Circassians are studied: index of endogamy, ethnic mar- riage assortativity, intensity of metisation, and Malecot's parameters of isolation by distance.

Based on data collected from urban residents by questionnaire, the basic parameters of the genetic-demographic structure of populations of the three megalopolises, i.e., Moscow, Kharkov, and Minsk, have been calculated, including the migration coefficients and their dynamics in generations, the radius of the cities migration attraction, the parameters of marriage structure (the proportion ofinterethnic marriages, the level of intraethnic assortative mating, the marital distances), and the gene flow between the ethnic groups. It is shown that the representatives of the most numerous ethnic groups in each megalopolis have considerable amount of admixture. For Russians of Moscow, Ukrainians of Kharkov, and Belarusians of Minsk, the proportion of individuals whose ancestors were all born in the given city for at least three generations and belonged to the same nationality turned out to be very low (4.75% in Moscow, 1.83% in Kharkov, and 3.13% in Minsk). This finding questions the formation of a reference population in the megalopolis as a sampling of aboriginals of certain ethnic origins. In the paper, we justify principles of creating genetic databases for the population of the megalopolis taking into account the complexity and dynamism of its population structure.

Marriage structure has been analyzed in the populations of the administrative centers of five uluses of the Republic of Sakha (Yakutia). The populations studied differ from one another with respect to ethnic composition, namely in the ratio between the indigenous and immigrant populations (the indigenous populations are larger in three uluses), in the proportions of representatives of indigenous ethnic groups among men and women contracting marriages, and in the frequencies of monoethnic and interethnic marriages. Positive assortative marriage among persons of the same ethnic group has been demonstrated. The total inbreeding estimated by isonymy (F(it)) varies from 0 to 0.007576.

A genetic demographic study has been performed in the city of Belovo with the use of the data on marriages contracted there in 1970 and 1994-1999. Marriage assortativeness with respect to age has been found to be the strongest and remain unchanged during the lifetime of one generation (r = 0.730 in 1970 and r = 0.801 in 1994-1999). Monoethnic marriages were substantially more frequent than interethnic ones in the Belovo population during the period studied, although the ethnic marriage assortativeness considerably decreased (K = 0.386 in 1970 and K = 0.141 in 1994-1999). Panmixia has been observed in the Russian population of Belovo. Other Eastern Slavs (Ukrainians and Belarussians) are characterized by negative marriage assortativeness and panmixia; positive marriage assortativeness has been found in other ethnic groups.

A method for reconstructing allele frequencies characteristic of an original ethnically homogeneous population before the start of migration processes is described. Information on both the ethnic group studied and offspring of interethnic marriages is used to estimate the allele frequencies. This makes it possible to increase the informativeness of the sample, which, in the case of ethnic heterogeneity, depends not only on allele frequencies and the total sample size, but also on the ethnic structure of the sample. The problem of estimating allele frequency in an ethnically heterogeneous sample has been solved analytically for diallelic loci. It has been demonstrated that, if offspring of interethnic marriages with the same degree of outbreeding is added to a sample of the ethnic group studied, the sample informativeness does not change. To utilize the information contained in the phenotypes of the offspring of interethnic marriages, representatives of the population from which migration occurs should be included into the sample. The size of the sample ensuring the preassigned accuracy of estimation is minimized at a certain ratio between the numbers of the offspring of interethnic marriages and the "immigrants." To analyze polyallelic loci, a software package has been developed that allows estimating allele frequencies, determining the errors of these estimates, and planning the sample ensuring the preassigned accuracy of estimation. The package is available free at http://mga.bionet.bionet.nsc.ru/PopMixed/PopMixed.html.

Marriage records have been used to study the marriage migration structure of five raions of the Rostov oblast. The mean ethnic marriage assortativeness in the Russian and Ukrainian rural populations are 1.16 and 1.6, respectively. The endogamy index of the urban population varies from 0.19 to 0.34; and that of the rural population, from 0.21 to 0.54. Malecot's isolation by distance parameters have been calculated. Genetic landscapes have been constructed.

The marriage structure of Nganasans during the time period from 1796 to 1991 and genealogy of carriers of mitochondrial DNA haplotypes was studied in a sample of 280 individuals. It was shown that, from the beginning of its formation to the late 1970s, the population exhibited high endogamy (1976, 83.8%; 1926, 88.4%; 1976, 74.3%). The main source of traditional marriage migration (preferentially female) was populations of Entsy and, indirectly, Nentsy. Intense assimilation of Nganasans by the immigrant population, and to a lesser extent, by Dolgans, in the second half of the 20th century resulted in a reduction of endogamy index in Avam Nganasans to 42.5% by 1991. Assimilation by the immigrants was predominantly paternal, promoting preservation of the historically formed genetic diversity of the Nganasan mitochondrial gene pool. Genealogical analysis of mtDNA haplotypes showed that a relatively high total frequency of Western Eurasian mtDNA haplogroups (20.4%) in the Mongoloid (according to anthropological type) Nganasan population is explained not only by the common ethnic origin with Entsy and Nentsy, but also by direct marriage migration from the Entsy population and indirect marriage migration, from the Nentsy population. This migration led to accumulation of Entsy-Nentsy maternal lineages in the genealogy of Avam Nganasans (38.9% of the total number). Of all mtDNA haplotypes, 28.6% were introduced to Avam Nganasans by female Entsy and Nentsy, whereas the total frequency of these haplotypes was 0.204. Genetic diversity of mitochondrial DNA haplotypes was 0.935.

Blood lipid composition was studied in 507 Selkups, native population of Tyumen Province (199 males and 308 females), 245 Slavs living in the north for more than 5 years (97 males and 148 females), 189 first generation métis born in mixed marriages (68 males and 121 females). Three age groups were analyzed: 10-19 (group 1), 20-39 (group 2), 40-59 (group 3). Male métis from groups 1, 2 and 3 had the highest levels of HDLP cholesterol, the lowest of apoB and atherogenic index. Group 2 métis were in the intermediate position between Slavs and Selkups by concentrations of total and LDLP cholesterol and triglycerides. Group 3 métis males had the lowest levels of triglycerides and intermediate levels of total and LDLP cholesterol. Group 1 and 2 métis females had the highest levels of LDLP, the lowest of apoB and low atherogenic index. In group 3, levels of total cholesterol, LDLP cholesterol, apoB and atherogenic index were as high as in non-aboriginal Slavonic population.

It was detected that the migration coefficient of Poltava's population increased from m = 0.68 in 1960 to 0.71 in 1985. The coefficient of coincidence of married pairs in nationality and origin decreased from K = 0.152 and K = 0.055 to K = 0.119 and K = 0.043 and increased from K = 0.085 to 0.095 according to their occupation. Potential selection index comprised I = 0.1798.

Positive assortative mating for birthplace and nationality has been revealed by means of sample analysis of couples married in two districts of Kharkov in 1960 and 1985. The contingency coefficient measuring the association between birth places of husband and wife was K = 0.15 in one district in 1960 and K = 0.18 in the other, these values being K = 0.16 and K = 0.18 for these districts, respectively, in 1985. A higher degree of assortative mating was observed for the nationality character: K = 0.40 and K = 0.21 in 1960 and K = 0.23 and K = 0.25 in 1985. The mean marriage substance increased from 578 to 699 km for 25 years.

A demographic genetic investigation of migration and marriage structure of the population of Alma-Ata was carried out on the basis of total analysis of marriage certificates issued in 1954 and 1984. The marriages were analysed in relation to birth places and nationality of married couples. An increase in the quantity of international marriages was noted, from 20.77% in 1954 to 22.85% in 1984 (p less than 0.05) in the population studied. The rate of international marriages for various nationalities was determined. Positive assortative mating, according to national indications, was proved in all basic national groups of the population. Negative correlation between the size of definite national groups and the coefficient of assortative mating was found. The quantitative and territorial-geographical characteristics of migration are presented. The proportion of married natives of Alma-Ata was 10.7% in 1954 and 34.4% in 1984, the increase being significant. The territorial-geographical character of migration also changed: so, in 1954 the basic flow of migrants came from Siberia and the European part of the USSR, while in 1984 they came from neighbouring regions of Alma-Ata. The migration activity both of men and women was identical. Thus, the shortening of migration radius and lowering of migration intensity are marked. The population of the large multinational cities is proved to be not panmictic.