Endogamy Rates Research Articles

Marriage patterns in the Western French Pyrenees during the 1800–1899 period: data from the village of Béost (Ossau Valley, Béarn)

The Western Pyrenees are made up of isolated valleys that were associated until recently with low marriage mobility. We chose to study the Ossau Valley (Bearn, France), which has one of the least mobile populations in this area. Marriage patterns in the village of Beost were analyzed over the 1800-1899 period. Data on 238 marriages obtained from parish, civil and notarial registers were used to assess the following variables: seasonality, endogamy rate, isonymic marriages and the consanguinity coefficient calculated from isonymy and from ecclesiastical dispensations. A clear seasonal marriage pattern emerged, linked to religious and local social parameters. Levels of endogamy were 57.5% in the village and 92.4% in the valley as a whole. The consanguinity coefficients calculated from isonymy (Ft) and ecclesiastical dispensations (α) were 0.0031 and 0.0040 respectively. The negative non-random component of F (Fn) indicated that Beost residents avoided contracting potentially consanguine isonymic marriages. These biodemographic markers were compared to those observed among various other 19th century mountain populations in Western Europe.

Founder mutations in Tunisia: implications for diagnosis in North Africa and Middle East

BackgroundTunisia is a North African country of 10 million inhabitants. The native background population is Berber. However, throughout its history, Tunisia has been the site of invasions and migratory waves of allogenic populations and ethnic groups such as Phoenicians, Romans, Vandals, Arabs, Ottomans and French. Like neighbouring and Middle Eastern countries, the Tunisian population shows a relatively high rate of consanguinity and endogamy that favor expression of recessive genetic disorders at relatively high rates. Many factors could contribute to the recurrence of monogenic morbid trait expression. Among them, founder mutations that arise in one ancestral individual and diffuse through generations in isolated communities.MethodWe report here on founder mutations in the Tunisian population by a systematic review of all available data from PubMed, other sources of the scientific literature as well as unpublished data from our research laboratory.ResultsWe identified two different classes of founder mutations. The first includes founder mutations so far reported only among Tunisians that are responsible for 30 genetic diseases. The second group represents founder haplotypes described in 51 inherited conditions that occur among Tunisians and are also shared with other North African and Middle Eastern countries. Several heavily disabilitating diseases are caused by recessive founder mutations. They include, among others, neuromuscular diseases such as congenital muscular dystrophy and spastic paraglegia and also severe genodermatoses such as dystrophic epidermolysis bullosa and xeroderma pigmentosa.ConclusionThis report provides informations on founder mutations for 73 genetic diseases either specific to Tunisians or shared by other populations. Taking into account the relatively high number and frequency of genetic diseases in the region and the limited resources, screening for these founder mutations should provide a rapid and cost effective tool for molecular diagnosis. Indeed, our report should help designing appropriate measures for carrier screening, better evaluation of diseases burden and setting up of preventive measures at the regional level.

History, geography and population structure influence the distribution and heritability of blood and anthropometric quantitative traits in nine Sardinian genetic isolates

Isolated founder populations which exhibit great genetic and environmental homogeneity provide an attractive setting for the study of quantitative traits (QTs). Geneticists have repeatedly turned to population isolates and the past successes have prompted increased interest among medical researchers. We studied nine small isolated villages of a secluded area of Sardinia (Ogliastra), all of them characterized by a few founders, high endogamy rates, slow population expansion and a distinct genetic makeup. Anthropometric and blood parameters, 43 QTs in all, were analysed in about 9000 voluntary subjects for whom extended genealogical information was available. We explored the distribution and examined mean differences of each trait among villages by analysis of variance (ANOVA). A heritability analysis with the variance component (VC) method was performed. Results show significant differences in the distribution of most traits between groups of villages located in two distinct geographical areas already identified by a previous population structure analysis, thus supporting the existence of differentiation among sub-populations in the same region. Heritability estimates range between 30 and 89%, demonstrating that genetic effects substantially contribute to phenotypic variation of all investigated traits and that this population provides excellent research conditions for gene-mapping projects. Results suggest that history, geographic location and population structure may have influenced the genetic and phenotypic features of these isolates. Our findings may be useful for the ongoing linkage and association studies in these isolates and suggest that a thorough characterization of population is valuable to better identify genes or variants that may be rare in the population at large and peculiar to single villages.

Analysis of bibliographic references in Zootecnia Tropical

PurposeThe purpose of this paper is to analyze the bibliographic references contained in the scientific papers (articles and technical notes) published from 1985 to 2005 in Zootecnia Tropical (ZT), a scientific journal.Design/methodology/approachA retrospective descriptive study is conducted using one‐dimensional bibliometric indicators such as: output, bibliographic density, institutional affiliation, recentness of the documents cited, document typology, self‐citations and scientific collaboration. Univariate descriptive analysis is used to study the indicators.FindingsA total of 349 scientific papers (300 articles and 49 technical notes) are reviewed; output ranged from a maximum of 34 papers in 2001 to a minimum of four in 1990, with a mean of 15 papers per volume. The papers analyzed contain a total of 5,651 bibliographic references, with an average of 19 ± 9 references per paper; the largest number of references (19 ± 33) are found in the articles and the smallest (10.5 ± 13) in the notes. Venezuelan institutions account for 89 per cent of the papers and international institutions for the remain in 11 per cent; of the Venezuelan institutions, most (62 per cent) are National Institute of Agricultural Research (INIA) bodies and the rest universities and other organizations, especially the Universidad Central de Venezuela (UCV) and Universidad de Oriente (UDO). Universities are also among the most frequent international contributors, most prominently Marianga State University in Brazil and Tucumán National University in Argentina. Around 60 per cent of the references were more than ten years old when they were cited; 21 per cent were between five and ten years old and 19 per cent less than five years old. Journal articles, with 57 per cent, are the document type most frequently cited, followed by books, with 23 per cent; the rest consisted in postgraduate theses (3 per cent), undergraduate theses (2 per cent) and congress, conference and seminar proceedings (12 per cent). The self‐citation or endogamy rate in the journal is 4 per cent. Over half (53 per cent) of the papers are written by authors with the same affiliation. Inter‐institutional papers account for the remaining 47 per cent, with 34 per cent involving national collaboration, particularly between the INIA and the UCV; international co‐authorship comes to 13 per cent, primarily involving Brazilian and Argentine universities.Originality/valueThis paper analyzes the use of information in the Venezuelan scientific community from the vantage of a specific journal, ZT. These studies constitute useful and objective tools for evaluating scientific activity.

FERTILITY PATTERN AND FAMILY STRUCTURE IN THREE ALPINE SETTLEMENTS IN SOUTH TYROL (ITALY): MARRIAGE COHORTS FROM 1750 TO 1949

Stelvio, Martello and Curon, three villages of the Venosta Valley, South Tyrol (Italy), were recently included in a large genetic survey because of their isolation. This study focuses on the long-term reproductive behaviour of these villages. Family size, age at marriage and marital fertility were estimated based on a genealogy going back in the 17th century. Marriage behaviour was characterized by an elevated age at marriage and a large proportion of adults never getting married. Marital fertility was among the highest worldwide, because couples tried to use the short time at their disposal to have the largest possible number of children. Together with the already known null population expansion and high geographic endogamy rates, the reduced number of siblings who had the opportunity to get married could have favoured an increased genetic homogeneity.

Particularistic Education, Endogamy, and Educational Tourism to Homeland: An Exploratory Multi-dimensional Analysis of Jewish Diaspora Social Indicators

Two new indicators of Jewish identity—market penetration of educational youth tours to Israel and rates of participation in a second tour—are proposed, and considered together with three widely used indicators (endogamy rates, day school enrolment and tourism to Israel) to create a typology of Jewish Diaspora communities. Analysis of the data allows for creation of a three-dimensional typology along three axes: adult tourism to Israel, market penetration of Israel Experience tours, and endogamy. These indicators are useful in differentiating between Jewish populations in various Diaspora countries. Some Diaspora populations (including the large ones in the USA and France) seem to have a small but committed core, while much of the Jewish population is according to these indicators less involved. Other Diaspora populations (such as Mexico and South Africa) have broader participation according to the selected indicators. The Jews of the Former Soviet Union have weak participation according to all the indicators. These results provide a preliminary basis for comparison of Jewish life throughout the Diaspora.

Genetic epidemiological study of Bashkortostan Republic: The effect of genetic structure of population on the load of monogenic hereditary diseases

Here we present the data obtained during medical genetic examination of the population of five districts of Bashkortostan Republic (Burzyanskii, Baimakskii, Abzelilovskii, Salavatskii, and Arkhangelskii) populated with 168050 persons including 135748 Bashkirs. The study involved all the population of the districts including each ethnic group and was conducted according to standard protocol developed in the Laboratory of Genetic Epidemiology, Medical Genetic Research Center, Russian Academy of Medical Sciences. Based on segregation analysis, the values of prevalence rates of the major types of Mendelian pathology (AD, AR, and X- linked diseases) was calculated in five regions of the Republic as well as for Bashkirs alone. Significant differences in the prevalence rates of AD and AR pathologies between individual districts, in particular upon division in rural and urban population, was observed. The prevalence rates comparison of monogenic hereditary pathology among Bashkirs compared to other previously examined populations have shown that the patterns of the hereditary disease load in the inspected districts of Bashkortostan were similar to that observed in the population of some districts in Udmurtia, Marii El and Chuvashiya. Russian European populations have shown significantly lower load of hereditary diseases. Correlation analysis of local inbreeding, endogamy and prevalence rates of AD and AR pathologies has shown that development of hereditary diseases load is significantly affected by gene drift.

Genetic profiling of Mycobacterium tuberculosis in Tunisia: predominance and evidence for the establishment of a few genotypes

Typing analyses of 378 Mycobacterium tuberculosis isolates collected between the years 2001 and 2005 from three northern representative regions of Tunisia revealed a highly homogeneous population. Indeed, 84.9 % of all tuberculosis (TB) cases were attributed to the Haarlem, LAM or T families. Strikingly, within each family, more than 60 % of TB cases were due to a single genotype. ST50 (Haarlem3) and ST42 (LAM9) genotypes were exceptionally predominant, representing 46.3 % of all typed isolates. ST50 showed an increased tendency for clustering and was more predominant in the extreme north of the country. By contrast, the more widespread ST42, which was apparently prevalent 17 years ago, displayed weak cluster individualization and a low transmission rate, consistent with its stable association with the Tunisian population. It is believed that both mass BCG vaccination, strictly applied for four decades, and the high endogamy rate that characterizes the Tunisian population could have profoundly shaped the population structure of M. tuberculosis by concurrently favouring the selection and accommodation of particular genotypes.

Genetic structure of the red mangrove (Rhizophora mangle L.) on the Colombian Pacific detected by microsatellite molecular markers

Rhizophora mangle, one of the five species of the genus Rhizophora, is found widely distributed along the American and West African coasts. This species is one of the principal constituents of the mangrove ecosystem in Colombia and is also found within the most important economic activities for the communities that inhabit the littoral. In order to assess the degree of genetic diversity of R. mangle in five populations of the Colombian Pacific, nuclear microsatellite molecular markers were used. In 92 individuals sampled, it was found that 100% of the loci were polymorphic \( (\overline H _0 = 0.494) \), and no private alleles were detected. The population structure of R. mangle in the Colombian Pacific, was highly significant (P < 0.001); however, the greatest differentiation was detected at the within-population level (94.62%). For the populations of La Plata, Virudo and Charambira, the tendency toward panmixia could be the cause of the low differentiation among these three locations. Within populations, the genetic diversity revealed a deviation from Hardy–Weinberg equilibrium with high significance in Virudo and Tumaco, where it appears the intense anthropogenic activity has exercised strong pressure on the red mangrove, resulting in the possible fragmentation of the local landscape and therefore an increase in the rate of endogamy within these populations. Despite this situation, our study―one of the first developed in genetics of the red mangrove in Colombia―did not show evidence of recent bottleneck effects or deterioration in its genetic composition, which could be exploited to propose management and restoration programs for the zones where the forests of this species are degraded.

Translation de Domicile: Rethinking Sedentarity and Mobility in the Early Modern French Countryside

Was the countryside of early modern France marked fundamentally by mobility or sedentarity? Tax rolls suggest the former, high endogamy rates the latter. For the period 1660-1720, a rarely used source, the registers of translation de domicile (change of tax domicile), provide a more comprehensive answer than civil or tax records. They suggest that, first, 60,000-70,000 better-off families moved each year; second, poor migrants, such as day labourers, rarely made declarations; third, those who owned land, moved far less often; fourth, laboureurs typically moved between 10 and 40 kilometres to take on farms of greater importance; fifth, cottagers and day labourers moved to a nearby village, rarely more than 5 kilometres away and finally, men and their families moved for economic gain, whereas women moved because of economic loss, after the death of their husband. Because the laboureurs dominated the villages-for example, paying most of the taxes-their movement shook the village in fundamental ways. The translation de domicile registers indicate villages open to the outside, full of in-migrants, whose economic status often bore a close correlation to the distance of their move (high-long, low-short).

Immigrant Positioning in Twentieth-Century Mexico: Middle Easterners, Foreign Citizens, and Multiculturalism

Immigrant Positioning in Twentieth-Century Mexico: Middle Easterners, Foreign Citizens, and Multiculturalism

Does 'Ethnic Capital' Matter? Identifying Peer Effects in the Intergenerational Transmission of Ethnic Differentials

An instrumental variables strategy is employed to determine whether the observed association between individual human capital and average skills in ethnic groups (ethnic capital), even after conditioning on parental skills, is due to ethnic peer effects. The instrument for ethnic capital is derived from the occupational mix of US immigrants arrived in the 1900's and 1910's, while father's age at arrival instruments for parental skills. Using US Census data on adult literacy in English and children's school attendance, I find evidence of a persistent ethnic capital effect. High geographic concentration and high endogamy rates tend to accentuate this effect.

Biodemographic and molecular analysis of an isolated Alpine population (Postua)

Isolated populations have been the object of several genetic and anthropological studies, since endogamy and inbreeding often lead to the acquisition of a particular gene pool. In this context, we studied the small, ancient population of Postua in the north-western Italian Alps. We used biodemographic and molecular techniques to analyse the population structure in order to evaluate the relationship between geographical and genetic isolation. We examined about 26,000 certificates kept in the town and parish archives, concerning the period from 1640 to 1999. High rates of endogamy and isonymy, short marriage distances and a low ratio between the number of surnames and the number of individuals were inferred. In the molecular analysis, we compared the distribution of Y chromosome SNPs (single nucleotide polymorphisms) with those of mitochondrial variations and Y chromosomal microsatellites (short tandem repeat polymorphisms) in 102 healthy individuals originating from Postua. A control sample (94 individuals) was collected from a plain area, 50 km away. We examined 23 SNPs and an Alu repeat, located in the nonrecombinant portion of the Y chromosome. To further delineate Y chromosome lineages, the biallelic haplogroups were further resolved using Y microsatellite markers (DYS19, DYS391, DYS392, DYS393). Mitochondrial HVS-I and HVS-II regions were sequenced, and RFLP screening with the six classical enzymes was performed. Postua is similar to other populations living in northern Italy, but it shows a lower number of haplotypes. The samples were compared with other European populations. We calculated genetic distances according to Reynold and Nei and we carried out a phylogenetic analysis by phylogenetic trees and reduced median networks construction. Postua clusters with other samples from northern Italy but in a separate position, probably indicating drift phenomena. These relationships are supported by AMOVA (analysis of molecular variance). Our results suggest that the influence of neighbouring populations on the gene pool of Postua has been very low through both females and males.

Reproductive isolation in Roio, a pastoral community of the Province of L’Aquila (Abruzzo, Italy) in the period 1800–1965

The present work refers to the study of reproductive isolation in Roio, a pastoral community in the Province of L’Aquila (Abruzzo), as part of a research project aimed at studying human isolates in the Central Apennines from an ecological viewpoint. Results relating to 1470 records of marriages from parish books show: 1) rates of endogamy around 80% in both centuries, the lowest so far found in the Province of L’Aquila. 2) Rates of consanguineous marriages average 12% in both centuries with an increasing trend in the period 1860–1930. 3) Inbreeding coefficients are 3–3.5×10−3 on average in both centuries, the highest so far found in the Province of L’Aquila, with the maximum value of 5.3×10−3 in the period 1880–99. Of relevance is the contribution of marriages between 1st and 2nd cousins in all periods and of oncle/neice and multiple consanguinity at the turn of the century. 4) Rates of isonymous marriages are 5.4% and 10% in the two centuries. 5) Inbreeding coefficient Ft is 0.0137, on average, in the 1800s and 0.025, almost doubled, in the 1900s. Its progressive increase with time is due both to the random and non-random components, thus suggesting increasing conditions of isolation and drift and a persistent tendency of celebrating unions between relatives.

Orofacial analysis on the Adriatic islands: an epidemiological study of malocclusions on Hvar Island.

The prevalence of malocclusion was studied on the Hvar island, Croatia. This island is characterized by high rates of endogamy, inbreeding and reproductive isolation. The sample for this study comprised 224 children, 126 males and 98 females from all schools on the island of Hvar (20.2 per cent of the total public school population). The sample was selected according to age, sex distribution, and demographic characteristics. The Angle Classes, overjet, overbite, crowding, spacing, and the type of anterior bite were examined. Class I buccal relationship was found in 47.3 per cent of the subjects, Class II in 45.1 per cent, and Class III in 5.4 per cent. Normal overjet was the most frequent finding (69.9 per cent). Normal overbite was seen in 42.5 per cent, deep in 49.1 per cent, and very deep in 2.7 per cent of the cases. Open bite was diagnosed in seven subjects (3.1 per cent) and edge-to-edge bite in six (2.7 per cent). The frequency of crowding was 57.1 per cent, normal relationships were observed in 34.9 per cent, and spacing in 8 per cent. The results of this investigation showed that the inhabitants of Hvar, who are characterized by a high rate of inbreeding and traditional diet, have more Class II malocclusions, deep bites, and midline shifts than the general Croatian population but not higher than other modern urbanized groups. Since the lack of chewing stress in this population cannot be considered as the main explanation for the above phenomenon, the genetic influence on the development of these occlusal traits in the inbred population of Hvar requires further investigation.

Biodemographic study of a central Apennine area (Italy) in the 19th and 20th centuries: marriage seasonality and reproductive isolation.

This study investigates seasonality of marriages and reproductive isolation in six long-isolated communities in the central Apennines (Italy). It had two objectives: (1) the identification of an Apennine biodemographic model in comparison with mountain communities of other regions, and with non-Apennine communities in Abruzzo, and (2) to identify the possible effects of the drainage of Lake Fucino (1854-1876) on that area. Marriages in this region show two very stable seasonal patterns: one is typical of sedentary rural societies, with summer migrations and marriages preferentially celebrated in the winter, and the other has marriages that are strongly concentrated in the summer months, i.e. between 75% and 93.5% of marriages were celebrated between June and October in these communities in the 1800s. These were traditionally pastoral communities with winter transhumance of the flocks and their shepherds towards the lowlands of southern Italy. In both groups, restrictions imposed by the Catholic Church do not seem to have affected the timing of marriages. Indeed, economic factors related to work activities seem to have had more influence. Concerning reproductive isolation, the results show high rates of endogamy: between 85% and 98% in both the 19th and 20th centuries. Rates of consanguineous marriages were between 5% and 20%, and those of isonymous marriages rarely exceeded 9%. The coefficient of inbreeding a shows that there was a delayed, limited period of increased consanguinity in the few decades around the turn of the century. This is different from the national situation, and thus could be a consequence of the Lake Fucino drainage.

Seletividade por cor e escolhas conjugais no Brasil dos 90

Este artigo se propõe analisar os padrões de preferências na escolha dos parceiros por grupos raciais, tal como estes grupos são definidos nas pesquisas realizadas pelo IBGE, utilizando as informações fornecidas pelas PNADs de 1995 e 1996. As uniões foram classificadas em dois tipos: endogâmicas e exogâmicas, segundo as categorias de cor dos cônjuges. Na primeira parte do artigo são apresentadas as características gerais da nupcialidade por cor para o total do Brasil e por regiões. Na segunda parte, são estudados dois aspectos da composição das uniões segundo a cor dos cônjuges: as tendências diferenciais para a endogamia matrimonial e a seletividade marital no comportamento exogâmico. O trabalho se propõe aprofundar o estudo da formação de uniões e casamentos inter-raciais junto com alguns aspectos dos processos sociais nela incluídos. Assim, com a finalidade de estimar o grau de seletividade racial que opera nas escolhas conjugais, no presente trabalho foram calculadas, a partir dos dados das PNADs 87 e 95, as proporções de uniões formadas dentro de cada grupo de cor, que denominamos taxas de endogamia e que nos fornecem o material de base para nosso estudo.

Marriage behaviour in the Alpine Non Valley from 1825 to 1923

The study is part of a research project on the marital structure of mountain populations from the Eastern Italian Alps. Little is known about marriage patterns in this Alpine area. The aim of the study is to evaluate the extent of reproductive isolation in some communities of the Non Valley (Trentino, Italy) and to investigate its microgeographic and temporal changes over the period 1825-1923. 4518 microfilmed marriage records from registers of seven parishes of the Non Valley were used to analyse the following: endogamy rate, inbreeding calculated both from dispensations and from isonymy, repeating pairs of surnames in marriages, isonymic relationships. The results show notable variability among parishes in the levels of endogamy (40-73%), inbreeding (alpha: 1.9-4.57; Ft: 0.0073-0.019) and subdivision (RPr/RP: 0.5-1.3). The values are relatively stable over the course of a century, apart from a rise in inbreeding indicated by dispensations and a slight decrease of endogamy at the beginning of the 20th century. Isonymic relationships reflect geographic proximity between populations, with minimum changes through time. Variations in the level of reproductive isolation within the Non Valley are consistent with the different geographic characteristics and population sizes of the settlements. Comparison with data obtained from previous studies in the Eastern Italian Alps shows that the values of the investigated biodemographic indicators are in line with the geography and altitude of the area. The slight differences in temporal trend of endogamy and inbreeding can be correlated with different migration patterns.

Not of Pure Blood: The Free People of Color and Racial Prejudice in Nineteenth-Century Puerto Rico

This is a most welcome addition to the still relatively limited literature on the free persons of color in the slave societies of America and should be required reading for all those interested in these themes. The free colored of Puerto Rico were a very large part of the total insular population from the earliest eighteenth-century censuses onward. They were three to four times greater than the slave population and reached 127,000 by 1830—by then representing almost 40 percent of the total population. Out of this group the author has selected those who lived in the city of San Juan—a sample of probably less than 5 percent of this total class—to study in detail. While this sample eliminates the majority of free persons of color who were rural residents and farmers, Kinsbruner nevertheless compensates for this with a wealth of archival detail on the life of this urban minority. He very skillfully uses the property and population census in the first quarter of the nineteenth century to explain residential patterns by color, occupational mobility, and marriage arrangements among the free colored. The resulting picture is quite remarkable and complex: a group of persons just one of two generations out of slavery who already were active and competitive members of the society and economy. They were a significant group of property owners and could be found in all skilled occupations; in fact, there were even two free colored women master silversmiths working in Ponce and San Juan. He shows in great detail the remarkable lack of housing segregation which existed in early-nineteenth-century San Juan. His analysis of housing segregation, in fact, is quite original and is one of the very few such studies to be found in the literature.On the other hand, his study of the selection of marriage partners shows the strong role of prejudice in the resulting high endogamy rates by race. He also finds relatively low rates of marriage for free colored and relatively high ratios of free colored families headed by single women, though whites also were well below traditional norms. From mid-nineteenth-century data for the island as a whole, he also shows the expected finding that the free colored had both higher birth and death rates than the richer white population among whom they lived. Finally, these same mid-century insular data shows modestly high and relatively equal rates of literacy for free colored women and men in several municipalities in the island.In this otherwise admirably written, analyzed and argued book, there are a few issues that other historians will debate. The rather broad usage of the term “caste” is confusing. Since the author does not put the term in quotes or use the Spanish term casta, he seems to suggest that this is a classic Indian-style caste system, which is definitely not the case here. He also tends to ignore the slave origins of this class of free persons and their much lower rates of initial capital and savings compared to whites, which may account for some of the differences he encounters. His attempts to use the unbalanced sex ratios of this small urban population (common to all urban populations in Latin America) to discuss economic inequalities due to prejudice, is not convincing. The same may be said for his attempts to generalize from the very small differences of average age by sex. Finally he ignores the fact that the whites often are as different from the norm he holds of marriage organization as are the free colored, which suggest some special patterns within the island’s own social structure. Despite these reservations, the data and analysis of this important study provide one of the few well grounded portraits we have of the urban free colored under slavery for any area of Spanish or Portuguese America and will be much used and appreciated by all scholars working on African slavery and race relations in the Americas.

Intergroup Marriage: An Examination of Opportunity Structures

Though a number of authors have noted the increase in interracial marriages in the United States over the past few decades, few researchers have systematically examined variables that affect the opportunity for intergroup marriage among several different groups: Whites, African Americans, Asians, and Hispanics. In this paper we examine several “opportunity” variables and their relationship to intergroup marriage for couples age 40 or younger: immigration, military service, metropolitan residency, age, region, college attendance, and socioeconomic status. We examine these relationships for African, White, Asian, and Hispanic Americans. Results for both males and females are presented. The analysis is based on data from the 1990 census. The propensity to marry within one's own group dropped slightly for all groups but Asian Americans from 1980 to 1990. White and Black Americans continue to have the highest endogamy rates. Hispanic and Asian Americans have lower rates, and regional variations are highest for them as well. The results suggest that the opportunity variables are important factors affecting rates of intergroup marriage.