New method for surname studies of ancient patrilineal population structures, and possible application to improvement of Y-chromosome sampling

Several studies showed that surnames are good markers to infer patrilineal genetic structures of populations, both on regional and microregional scales. As a case study, the spatial patterns of the 9,929 most common surnames of the Netherlands were analyzed by a clustering method called self-organizing maps (SOMs). The resulting clusters grouped surnames with a similar geographic distribution and origin. The analysis was shown to be in agreement with already known features of Dutch surnames, such as 1) the geographic distribution of some well-known locative suffixes, 2) historical census data, 3) the distribution of foreign surnames, and 4) polyphyletic surnames. Thus, these results validate the SOM clustering of surnames, and allow for the generalization of the technique. This method can be applied as a new strategy for a better Y-chromosome sampling design in retrospective population genetics studies, since the idenfication of surnames with a defined geographic origin enables the selection of the living descendants of those families settled, centuries ago, in a given area. In other words, it becomes possible to virtually sample the population as it was when surnames started to be in use. We show that, in a given location, the descendants of those individuals who inhabited the area at the time of origin of surnames can be as low as approximately 20%. This finding suggests 1) the major role played by recent migrations that are likely to have distorted or even defaced ancient genetic patterns, and 2) that standard-designed samplings can hardly portray a reliable picture of the ancient Y-chromosome variability of European populations.     

中国人姓氏群体遗传Ⅱ. 姓氏传递的稳定性与地域人群的亲缘关系

分析了比较了宋朝、明朝和当代姓氏的分布曲线,同姓率（ｉｓｏｎｙｍｙ）和地域人群间的亲缘关系。３个历史时期的姓氏分布反映了２个重要的现象;第一,中国人姓氏在历史上是连续的和稳定的。它揭示了姓氏所表现的血缘文化的痕迹与生命遗传物质,尤其是Ｙ染色体的进化具有基本相同的和平行的表现,第二,中国人的姓氏存在２种状态,常见姓氏和非常见姓氏。仅占总姓氏上５％的１００个常见姓氏集中了８５％以上的人口,而占总姓氏量     

The Surname Space of the Czech Republic: Examining Population Structure by Network Analysis of Spatial Co-Occurrence of Surnames

In the majority of countries, surnames represent a ubiquitous cultural attribute inherited from an individual''s ancestors and predominantly only altered through marriage. This paper utilises an innovative method, taken from economics, to offer unprecedented insights into the “surname space” of the Czech Republic. We construct this space as a network based on the pairwise probabilities of co-occurrence of surnames and find that the network representation has clear parallels with various ethno-cultural boundaries in the country. Our inductive approach therefore formalizes a simple assumption that the more frequently the bearers of two surnames concentrate in the same locations the higher the probability that these two surnames can be related (considering ethno-cultural relatedness, common co-ancestry or genetic relatedness, or some other type of relatedness). Using the Czech Republic as a case study this paper offers a fresh perspective on surnames as a quantitative data source and provides a methodology that can be easily incorporated within wider cultural, ethnic, geographic and population genetics studies already utilizing surnames.     

Mating pattern and population structure in Escazú, Costa Rica: a study using marriage records

A primary focus of historical demographic research is to understand how a population's mating pattern can affect its genetic structure. By using surnames, researchers can reconstruct gene flow into a population as well as within it: the population structure. Indeed, Lasker (1988a) noted that the distribution of surnames reflects the effect of mate choice on a population's genetic structure. Here, we study the mating pattern of a small, clearly established breeding population in Costa Rica (Escazú) during 1800-1839 and 1850-1899. We found that a large proportion of marriages involved individuals who were members of long-standing or core families. Indeed, 27 families provided 56% of all consorts throughout the period under study. When new surnames appeared in the records (presumably as a result of immigration), they were introduced more frequently by males, indicating that more males than females migrated into the community. The core families did not mate preferentially among themselves but appear to have readily accepted the migrants. Indeed,the greatest preponderance of repeated-surname marriages was that expected by chance. However, nonrandom surname repetition is evident when marriages between nonillegitimate consorts are analyzed. That is, the frequency of repeated-pair surname marriages is statistically significant in marriages involving brides and grooms who carried 2 surnames. Interestingly, significant departures from random repetition of surnames occurred during the decade in which the great cholera epidemic affected Costa Rica and during the decade following it. This departure from panmixia supports the notion that mating patterns were altered as a result of the epidemic, a suggestion we made previously when we reported that inbreeding increased in these same decades (Madrigal and Ware 1997).     

In the name of the migrant father--analysis of surname origins identifies genetic admixture events undetectable from genealogical records

Patrilineal heritable surnames are widely used to select autochthonous participants for studies on small-scale population genetic patterns owing to the unique link between the surname and a genetic marker, the Y-chromosome (Y-chr). Today, the question arises as to whether the surname origin will be informative on top of in-depth genealogical pedigrees. Admixture events that happened in the period after giving heritable surnames but before the start of genealogical records may be informative about the additional value of the surname origin. In this context, an interesting historical event is the demic migration from French-speaking regions in Northern France to the depopulated and Dutch-speaking region Flanders at the end of the sixteenth century. Y-chr subhaplogroups of individuals with a French/Roman surname that could be associated with this migration event were compared with those of a group with autochthonous Flemish surnames. Although these groups could not be differentiated based on in-depth genealogical data, they were significantly genetically different from each other. Moreover, the observed genetic divergence was related to the differences in the distributions of main Y-subhaplogroups between contemporary populations from Northern France and Flanders. Therefore, these results indicate that the surname origin can be an important feature on top of in-depth genealogical results to select autochthonous participants for a regional population genetic study based on Y-chromosomes.     

Surnames in the Study of Human Biology

Use of surname analysis in human population biology depends on surnames being inherited like genes. In societies that meet this condition, communities with a few surnames at high frequency are the more inbred ones, and marriages between persons of the same surname can be used to estimate rates of inbreeding. Furthermore, the degree of commonality of the surnames of two communities estimates their biological relationship provided that any two persons of the same surname derived it from a common ancestor and that virilocal and uxorilocal migration is equal. Although the assumptions are only partially met, the surname method yields results which correlate with the amount of marital migration and with geographical and historical features. Rare surnames meet the assumptions better than common ones. Documents, both old and new, yield surnames of large numbers of people which can easily be analyzed to show the cumulative effect of marital migration since the establishment of surnames (in England in the Middle Ages). Surnames thus serve to delineate the breeding structure of some human populations over a longer span of time than is usually possible with pedigrees, over a more definite span of time than in genetic studies, and more easily in broad surveys than alternative methods . [isonymy, surnames, inbreeding, coefficient of relationship, England]     

Analysis of marital structure in Massachusetts using repeating pairs of surnames.

Analysis of surnames from marriages is now a well-established method in the study of marital and genetic structure. Traditional methods of partitioning inbreeding into random and nonrandom components rely on the total number of isonymous marriages. Because this number is often low, standard errors of inbreeding estimates tend to be high. Lasker and Kaplan (1985) devised a method that circumvents this problem by focusing on the total number of repeating pairs (RP) of surnames among marriages. The observed value of RP can be compared with the value expected at random (RPr) to assess patterns of subdivision within a population. The RP method is applied here to data from 3431 marriages that took place from 1800 to 1849 in 4 Massachusetts towns. The level of excess RP [(RP-RPr)/RPr] is positively associated with population size and exogamy rate. These results indicate a tendency for greater relative subdivision in larger, more exogamous populations. One possible reason for increased subdivision is preferential marriage by social class, although adequate data are not available for a test of this hypothesis.     

Russian genofond. Genogeography of surnames

Surnames are traditionally used in population genetics as "quasi-genetic" markers (i.e., analogs of genes) when studying the structure of the gene pool and the factors of its microevolution. In this study, spatial variation of Russian surnames was analyzed with the use of computer-based gene geography. Gene geography of surnames was demonstrated to be promising for population studies on the total Russian gene pool. Frequencies of surnames were studied in 64 sel'sovets (rural communities; a total of 33 thousand persons) of 52 raions (districts) of 22 oblasts (regions) of the European part of Russia. For each of 75 widespread surnames, an electronic map of its frequency was constructed. Summary maps of principal components were drawn based on all maps of individual surnames. The first 5 of 75 principal components accounted for half of the total variance, which indicates high resolving power of surnames. The map of the first principal component exhibits a trend directed from the northwestern to the eastern regions of the area studied. The trend of the second component was directed from the southwestern to the northern regions of the area studied, i.e., it was close to latitudinal. This trend almost coincided with the latitudinal trend of principal components for three sets of data (genetic, anthropological, and dermatoglyphical). Therefore, the latitudinal trend may be considered the main direction of variation of the Russian gene pool. The similarity between the main scenarios for the genetic and quasi-genetic markers demonstrates the effectiveness of the use of surnames for analysis of the Russian gene pool. In view of the dispute between R. Sokal and L.L. Cavalli-Sforza about the effects of false correlations, the maps of principal components of Russian surnames were constructed by two methods: through analysis of maps and through direct analysis of original data on the frequencies of surnames. An almost complete coincidence of these maps (correlation coefficient rho = 0.96) indicates that, taking into account the reliability of the data, the resultant maps of principal components have no errors of false correlations.     

Autochthony and HLA frequencies in the Netherlands: when surnames are useless markers

To study the genetic variability of the HLA loci A, B, DR, and DQ in the Netherlands, we analyzed more than 13,000 typings provided by the Dutch National Reference Laboratory for Histocompatibility. To investigate any possibly existing population structure, we subdivided the typings by the geographic location of residency of donors and by the historical belonging of their surnames to given provinces. Concerning possible geographic patterns, we found no significant differences between the four provinces examined (North Holland, South Holland, Utrecht, Zeeland). To assess whether such a negative result was related to recent immigration to the area (the richest of the country) that erased possible preexisting patterns of HLA diversity, we reprocessed the database according to the surnames of HLA donors. We obtained two groups: (1) those having a surname typical of the four provinces they inhabit and (2) those with surnames coming from elsewhere. Such an analysis was made possible because of the availability of a database concerning the geographic origin of most Dutch surnames. Even with this surname-based approach, no major differences were found. We conclude that either the western part of the Netherlands was genetically homogeneous before the official introduction of Dutch surnames two centuries ago by Napoleon or surnames have no power in dissecting HLA variability; that is, such variability is the result of recombination phenomena that surnames cannot mirror because they are transmitted virtually unchanged generation after generation. A comparable study by other investigators recommended the use of family names to identify rare HLA haplotypes in France, but now, concerning the Netherlands, we find opposite results. We suggest that a few typing centers may be sufficient to type bone marrow donors, because HLA genetic differences between the different provinces of the Netherlands are extremely low. To maximize the number of donors, such centers should be located in areas providing the easiest access to the largest population of possible donors, thus disregarding the search for a local variability that we did not find.     

Repetition of the same pairs of names in marriages in Fogo Island,Newfoundland, and genetic variation

Surnames can be used to investigate the genetic structure of human populations. The repeated-pairs approach (RP) uses information on the repetition of the same pairs of names from marital data sets to indicate the influence of clanlike behavior on mate choice. RP estimates the subdivision of the population into subgroups that breed among themselves and the kind of inbreeding ascribed to the Wahlund effect. The application of this method to the Fogo Island, Newfoundland, data set indicates a large percentage excess of observed over random repetitions. Presumably at least a part of this excess in the island population is due to denominational subdivision and endogamy. The expected relationship between RP and heterozygosity is observed in this case. Given these results, it would seem worthwhile to explore the relationship between the frequency of repetitions of pairs of surnames in marriages and genetic variation in other populations as well and, at the same time, to begin to inquire into the validity of such assumptions concerning the use of surnames as the monophyletic origin of common names.     

Isonymy and the genetic structure of Albanian populations

It is well known that in systems of surname transmission through the paternal line, surnames simulate neutral gene alleles belonging to the Y chromosome. This property of surnames was used to analyze the genetic structure of Albanian populations. Two large samples of surnames belonging to two different periods of time were analyzed. The analysis of indicators of population structure showed that geographical distance has an important effect on surname distribution. It seems that isolation by distance and genetic drift have been still important factors in the determination of the genetic structure of the Albanian population.     

Genetic and cultural transmission in Sicily as revealed by names and surnames

The study of names as cultural characters and of surnames, which behave like genetic markers, is useful for comparing cultural and genetic transmission. Genetic transmission has a unique vertical component, which also can be present in the transmission of cultural traits associated with a horizontal (or epidemic) component resulting from local customs or fashion. Our aims in this study are to infer genetic patterns in Sicily from surnames and names and to evaluate and compare the consequences of vertical versus horizontal transmission of cultural markers. Names and surnames of 88,383 consanguineous spouses collected in 16 dioceses of Sicily were analyzed by multivariate analysis to reveal and compare the geographic clusters obtained from both sets of data. As a result, both data sets indicate a major separation between the eastern and the western region of Sicily. Also, distance matrices obtained from names are highly correlated with those from surnames. But names seem to form fewer and larger geographic clusters, whereas surnames are more greatly subdivided into smaller clusters. The most common male names present a different pattern from surnames. Vertical transmission is the cause of the similarity of the main geographic patterns of names and surnames and their correspondence with findings from geography of genes, and horizontal cultural transmission explains the major differences. Furthermore, the genetic and cultural affinities can be correlated with the historical background of Sicily.     

Genogeographic analysis of a subdivided population. II. Geography of random inbreeding (from frequency of surnames in Adygs)

An important characteristic of the genetic structure of populations, random inbreeding (interpopulation variation), was evaluated on the basis of quasi-genetic markers (surnames). The following methodological issues are considered: estimation of random inbreeding using the coefficient of isonymy fr in a subdivided population; a comparison of inbreeding levels calculated on the basis of surname frequencies using fr and Wright's FST; a comparison of inbreeding estimates obtained on the basis of surnames and genetic markers; inbreeding variation in populations of the same hierarchical rank; and planning of genetic studies of a subdivided population. The population of Adygs (an indigenous ethnic group of Northern Caucasus) was examined as a model subdivided population. The population system of Adygs is hierarchical. Parameters of random inbreeding were examined at each level of the system "ethnic group==>tribe==>geographic group of auls==>aul." Frequencies of surnames were collected subtotally. Data on frequencies of 1340 surnames in 61 auls representing all Adyg tribes were analyzed. In total, 60,000 people were examined. The inbreeding estimates obtained on the basis of Wright's FST and the coefficient of isonymy fr virtually coincided: for Adygs in general, FST x 10(2) = 2.13 and fr x 10(2) = 2.09. At the same time, the inbreeding level exhibited marked differences among tribes: in Shapsugs, these differences were an order of magnitude higher than in Kabardins (fr x 10(2) = 2.53 and 0.25, respectively). The inbreeding estimates for auls differed by two orders of magnitudes: fr x 10(2) = 0.07 and fr x 10(2) = 7.88. An analysis of ten auls yielded fully coinciding inbreeding estimates based on quasi-genetic (fr x 10(2) = 0.60) and classical (FST x 10(2) = 0.69) gene markers. Computer maps of surname distributions in Adygs (1340 maps) were constructed for the first time ever. Based on these maps, the map of random inbreeding in the Adyg population was obtained.     

Population structure of São Miguel Island, Azores: a surname study

The knowledge of a population structure may constitute a powerful tool for mapping genes underlying susceptibility to Mendelian and complex diseases. To obtain a better understanding of the population structure of S?o Miguel Island (Azorean Archipelago, Portugal), we carried out a surname survey using the surnames listed in the most recent telephone book (2001). We identified 1315 different surnames in a total of 27,621 subscribers. The frequency of the different surnames was used to calculate the following parameters: isonymy (I), random component of inbreeding (FST), genetic diversity according to Fisher (alpha), migration rate according to Karlin-McGregor (v) and Nei's genetic distance. Eleven localities were selected, according to population size and geographic distribution, for analysis using the above parameters. Our results show that 51% of Salga's population and 52% of Sete Cidades's population are represented by six and eight surnames, respectively. These figures demonstrate the effective isolation of these two small places, which are located at opposite ends of S?o Miguel Island. Salga, Achada, and Sete Cidades present the lowest values of Fisher's alpha, indicating less genetic diversity. In contrast, the capital, Ponta Delgada, presents the highest value of alpha (78.13), indicating more genetic diversity. Our data indicate that the clustering of the localities corresponds to the geographic features of the island, where localities close together tend to share similar surnames. In conclusion, the population of S?o Miguel is relatively homogeneous and may constitute an ideal model for genetic mapping studies.     

Surnames in the Azores: analysis of the isonymy structure

Geographic isolation is a significant factor to consider when characterizing human populations. The knowledge of the genetic structure of isolated populations has been of great importance to disease-locus positioning and gene identification. To investigate the genetic structure of the Azorean population, we conducted a survey based on the frequencies of surnames listed in the 2001 telephone book. We calculated the following parameters: isonymy (I), the random component of inbreeding (F(ST)), genetic diversity according to Fisher (alpha), Karlin-McGregor's migration rate (v), and Nei's distance. For the 1,271 subscribers and 163 different surnames, Graciosa island presented the lowest value of abundance of surnames (alpha = 15.75), suggesting great genetic isolation compared to the other eight islands. Migration, calculated on the basis of the diversity of surnames within islands, ranged from 0.2747 (Corvo island) to 0.0026 (S?o Miguel island), indicating that people migrated preferentially toward the economically more developed islands. The value of the random component of inbreeding obtained for the whole population (F(ST) = 0.0039) indicates little genetic differentiation (Wright's F(ST) < 0.05). Moreover, isonymy similarity revealed using the UPGMA method shows three subclusters corresponding to the geographic distribution of the islands.     

Do surname differences mirror dialect variation?

Our focus in this paper is the analysis of surnames, which have been proven to be reliable genetic markers because in patrilineal systems they are transmitted along generations virtually unchanged, similarly to a genetic locus on the Y chromosome. We compare the distribution of surnames to the distribution of dialect pronunciations, which are clearly culturally transmitted. Because surnames, at the time of their introduction, were words subject to the same linguistic processes that otherwise result in dialect differences, one might expect their geographic distribution to be correlated with dialect pronunciation differences. In this paper we concentrate on the Netherlands, an area of only 40,000 km2, where two official languages are spoken, Dutch and Frisian. We analyze 19,910 different surnames, sampled in 226 locations, and 125 different words, whose pronunciation was recorded in 252 sites. We find that, once the collinear effects of geography on both surname and cultural transmission are taken into account, there is no statistically significant association between the two, suggesting that surnames cannot be taken as a proxy for dialect variation, even though they can be safely used as a proxy for Y-chromosome genetic variation. We find the results historically and geographically insightful, hopefully leading to a deeper understanding of the role that local migrations and cultural diffusion play in surname and dialect diversity.     

Genetic structure of Flores island (Azores, Portugal) in the 19th century and in the present day: evidence from surname analysis

The island of Flores is the most westerly of the Azores archipelago (Portugal). Despite its marked geographic isolation and reduced population size, biodemographic and genetic studies conducted so far do not support the idea that its population constitutes a genetic isolate. In this study we conducted a surname analysis of the Flores population for two time periods: the second half of the 19th century and the present day. Our main purposes were (1) to biodemographically and genetically characterize the island, taking into account the strong reduction in population observed from the middle of the 19th century to the present day; and (2) to analyze the influence that the effective population size and geographic distance have on the genetic structure of populations. For both periods analyzed, all indicators of diversity revealed a high level of surname diversity. Our results are in accordance with the diversity estimates obtained from both monoparental genetic markers located in the Y chromosome and frequencies of mtDNA haplogroups. Contrary to what could be expected, considering the strong reduction of population in the last 150 years, we observed that diversity was maintained and that microdifferentiation decreased. Both observations support a higher openness of parishes as a consequence of the increase in communication routes. From the first to the second period analyzed, a change in surname composition is evident, although the more frequent surnames in Flores are almost the same for both periods and some of them are reported to be surnames present in the first settlers of Flores. This result testifies to the impact of founders on the present-day gene pool of Flores island and allows us to infer that the genetic characterization of the present-day population of Flores could provide reliable information about the history of the peopling of the Azores.     

深圳无偿献血人群中李姓、王姓和张姓无关男性个体Y-STR单倍型遗传多态性

为研究姓氏群体Y染色体特异STR单倍型的遗传多态性, 采用PCR复合扩增和ABI PrismTM 3100基因测序仪荧光检测方法对DYS426等9个Y-STR基因座进行基因分型, 检测深圳地区李姓无关男性个体血样139份、王姓无关男性个体118份、张姓无关男性个体119份。结果在139份李姓群体中, 共检出126种单倍型, 其中118种单倍型仅出现1次, 检出频率最高的1种单倍型出现6次, 单倍型多样性为0.9974; 118份王姓无关男性样本中, 共检出105种单倍型, 其中94种单倍型仅出现1次, 检出频率最高的1种单倍型出现4次, 单倍型多样性为0.9953; 张姓无关男性样本中, 共检出101种单倍型, 其中88种单倍型仅出现1次, 检出频率最高的1种单倍型出现4次, 单倍型多样性为0.9964。结果表明: 深圳地区李、王、张姓氏无关男性个体Y-STR单倍型的遗传多态性丰富, 与以往的汉族无关男性群体遗传资料相比较, 差异不显著。