Y-chromosomes and the extent of patrilineal ancestry in Irish surnames

Ireland has one of the oldest systems of patrilineal hereditary surnames in the world. Using the paternal co-inheritance of Y-chromosome DNA and Irish surnames, we examined the extent to which modern surname groups share a common male-line ancestor and the general applicability of Y-chromosomes in uncovering surname origins and histories. DNA samples were collected from 1,125 men, bearing 43 different surnames, and each was genotyped for 17 Y-chromosome short tandem repeat (STR) loci. A highly significant proportion of the observed Y-chromosome diversity was found between surnames demonstrating their demarcation of real and recent patrilineal kinship. On average, a man has a 30-fold increased chance of sharing a 17 STR Y-chromosome haplotype with another man of the same surname but the extent of congruence between the surname and haplotype varies widely between surnames and we attributed this to differences in the number of early founders. Some surnames such as O’Sullivan and Ryan have a single major ancestor, whereas others like Murphy and Kelly have numerous founders probably explaining their high frequency today. Notwithstanding differences in their early origins, all surnames have been extensively affected by later male introgession. None examined showed more than about half of current bearers still descended from one original founder indicating dynamic and continuously evolving kinship groupings. Precisely because of this otherwise cryptic complexity there is a substantial role for the Y-chromosome and a molecular genealogical approach to complement and expand existing sources.     

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.     

A Y-chromosome signature of hegemony in Gaelic Ireland

Seventeen-marker simple tandem repeat genetic analysis of Irish Y chromosomes reveals a previously unnoted modal haplotype that peaks in frequency in the northwestern part of the island. It shows a significant association with surnames purported to have descended from the most important and enduring dynasty of early medieval Ireland, the Ui Neill. This suggests that such phylogenetic predominance is a biological record of past hegemony and supports the veracity of semimythological early genealogies. The fact that about one in five males sampled in northwestern Ireland is likely a patrilineal descendent of a single early medieval ancestor is a powerful illustration of the potential link between prolificacy and power and of how Y-chromosome phylogeography can be influenced by social selection.     

Estimation of inbreeding,kinship and genetic distances from surnames--coastal population of middle Dalmatia,Croatia

This work was dedicated to the investigation of the population structure of the middle Dalmatia settlements: Jesenice, Mimice, Zivogos?e and Zaostrog by surname distribution study and applying the isonymous method. The surnames of males and females in marital pairs were analyzed as well as of their first and second-generation ancestors on the sample of a total of 3,024 examinees. The analyses of surnames pointed to the rates of inbreeding, kinship and genetic distances of the populations. Although the values of the inbreeding coefficient are high in all the four settlements, the inbreeding coefficient is exceptionally high in Mimice. A total kinship coefficient for the four settlements speaks also in favor of the high rate of kinship in the examined settlements, i.e. of the high rate of the reproductive isolation of the whole region during the analyzed period. The reasons for such high coefficients are natural features of the examined region (the mountains of Mosor, Biokovo and Rili?), poor traffic connection of this region in the past, the patrilineal mode of inheritance and the demographic specifics of the population. The matrix of genetic distances between examined settlement pairs reveals that Mimice, a settlement with the highest share of isonymous marriages, shows the greatest distances in comparison to the other settlements. On the other hand, Jesenice, Zivogos?e and Zaostrog are characterized by small genetic distances, which is the fact that speaks in favor of their genetic homogenization and "openness" toward interpopulational migrations, i.e. the gene flow.     

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.     

Culture modifies expectations of kinship and sex‐biased dispersal patterns: A case study of patrilineality and patrilocality in tribal yemen

Studies of the impact of post‐marital residence patterns on the distribution of genetic variation within populations have returned conflicting results. These studies have generally examined genetic diversity within and between groups with different post‐marriage residence patterns. Here, we directly examine Y chromosome microsatellite variation in individuals carrying a chromosome in the same Y haplogroup. We analyze Y chromosome data from two samples of Yemeni males: a sample representing the entire country and a sample from a large highland village. Our results support a normative patrilocality in highland Yemeni tribal populations, but also suggest that patrilocality is violated often enough to break down the expected correlation of genetic and geographic distance. We propose that a great deal of variation in male dispersal distance distributions is subsumed under the “patrilocal” label and that few human societies are likely to realize the idealized male dispersal distribution expected under strict patrilocality. In addition, we found almost no specific correspondence between social kinship and genetic patriline at the level of the clan (large, extended patrilineal kinship group) within a large, highland Yemeni village. We discuss ethnographic accounts that offer several cultural practices that explain exceptions to patrilocality and means by which social kinship and genetic patriline may become disentangled. © 2013 Wiley Periodicals, Inc.     

Isonymic relationships in ethno-social categories (Argentinian colonial period) including illegitimate reproduction

Surnames provide a useful method to study the structure of human populations for which biological data are not available. The isonymic method has had multiple applications, but difficulties emerge when dealing with groups where extramarital reproduction is common and the sample size is small, and even more so when only paternal surnames are taken into account.Therefore, it could be of interest to retain female surnames, including those of unmarried mothers. This study was carried out using all birth records froman Argentinian population in the colonial period, which was characterized by the presence of different ethno-social groups (Spanish, Indian and 'Mestizo'or mixed Spanish-Indian) and various reproductive patterns regarding legitimacy. Coefficient of relationship by isonymy (Ri) kinship matrices between geographical populations were obtained, and the results derived from sets of surnames (paternal, maternal of legitimate and illegitimate children,and all surnames in the registers) compared. The results show similar surname distribution regardless of the set of surnames and group considered.Kinship Ri matrices using paternal surnames, maternal surnames of legitimate children, maternal surnames of illegitimate children, and the set of whole surnames showed the same relationships among populations, indicating a similar pattern for Spanish, Indian and Mixed ethno-social groups. Mantel test correlation between all pairs of matrices was significant in all different ethno-social groups. The results suggest that in populations with high illegitimacy, such as that studied here, it is possible to include maternal surnames, even corresponding to single mothers, in order to consider total reproduction and therefore maximize sample size.     

Class endogamy, inbreeding and migration during the Argentinean colonial period: analysis based on individuals of European ancestry

During the Spanish colonial period, Córdoba was an important town due to its location suitable for controlling communication throughout a wide region of Argentina. As a typical colonial society, where individuals belonged to a well established social class, marriages among Whites were the result of strict norms and prejudices founded on nets of kinship, friendship and neighbouring. The objective of this paper is to determine, whether the elevated class endogamy among Whites during the colonial period resulted in high consanguinity and whether a process of selection of surnames was present in 1813. In both cases the interaction with the migratory flow was taken into account. It is concluded that (a) Although an endogamy of "class" existed among Whites, there is no evidence of the consequences on the biological structure of the population through preferential mating between relatives, as deduced from the low level of inbreeding from isonymy. (b) There was no differential reproduction reflecting the selection of families carrying certain surnames; therefore surnames followed a "neutral" model. (c) The diversity of surnames and the gene flow deduced from them were of a magnitude similar to present populations; this fact could have balanced the effect of the "class" endogamy. (d) Finally, the congruence between information derived from the population age distribution and historic data and the quantification of migration from surnames allowed the detection of mistakes in the census data file regarding the number of foreigners, thus validating the use of surnames as biological markers of the population structure.     

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.     

In the name of the father: surnames and genetics

Hereditary surnames contain information about relatedness within populations. They have been used as crude indicators of population structure and migration events, and to subdivide samples for epidemiological purposes. In societies that use patrilineal surnames, a surname should correlate with a type of Y chromosome, provided certain assumptions are met. Recent studies involving Y-chromosomal haplotyping and surname analysis are promising and indicate that genealogists of the future could be turning to records written in DNA, as well as in paper archives, to solve their problems.     

Testing isonymy with paternal and maternal lineages in the early Québec population: the impact of polyphyletism and demographic differentials

Isonymy is an ingenious and useful approach to studying kinship in human populations. However, it relies on assumptions that are difficult to verify. In this study, we provided a way to assess, in the early Québec population, the impact of factors such as polyphyletism, unbalanced sex-ratio among founders, and age differentials between spouses. All data were taken from the Population Register of Early Québec, which contains births, marriages, and deaths (>712,000) recorded in parish registers from the beginning of colonization (in 1608) to 1800. More specifically, using the 70,869 marriages recorded during that period, we compared kinship estimates given by genealogies, surnames, and paternal and maternal lineages. We also calculated a fifth coefficient of kinship by combining paternal and maternal lineage, thus providing a new way to test the isonymy method. The results show a good agreement between genealogical and isonymous estimates. However, this good correspondence is due to counterbalancing biases. Some of the implications of our results are discussed in the context of colonial America.     

Examination of the relationship between inbreeding and population size

This chapter presents a method for examining the relationship between effective population size and accumulated random inbreeding in human populations. Using a linear regression model on 9 Irish isolates, results show that this method is very useful in assessing differential influences on population structure. Inbreeding refers to the level expected at random due to finite population size, offset by migration into the population. The data used consist of effective population size estimates and kinship estimates derived from surnames for 9 isolates on, or near, the west coast of Ireland. Based on the non-parametric correlation results, there is no monotonic relationship between effective population size and the inverse of kinship. The demographic data available show that, with the exception of Garumna, Lettermullen, and the Aran Islands, the other populations changed little in population size during the latter part of the 19th century. The fact that observed kinship is higher than predicted kinship suggests an increse in population size. These analyses suggest that there is little, if any, relationship between population size and inbreeding among these populations, using 1891 effective population size estimates. Given the range of demogrphic, ecological, and cultural environments of human populations, perhaps it is unexpected to see a set of populations adhering strongly to a given theoretical model. The more important aspect of such model fitting is not whether or not a given model shows a significant fit, but rather the analysis of deviations from an expected relationship.     

Refusing to Sing: Gender,Kinship and Patriliny in Macedonia

The issue of whether formal kinship structures and sentiments reflect the reality of social relations was of particular concern to specialists at the height of the kinship debates in the 1960s and 1970s, as it continues to be in some contemporary studies. So too, the classifications ‘patrilineal’ or ‘matrilineal’ have clearly been shown to be problematic given that there are multiple levels of discourse and relational and ideational realities in any given society. For many contemporary kinship specialists in fact no simple correlation can be made between type of descent system and actual social relations, especially relations between men and women. However, some anthropologists continue to argue that patrilineal kinship systems are somehow indicative of control or domination by men or, put inversely, of women's lack of power and authority. It is argued in this paper that even where the formal kinship structures and ideological discourses are dominated by agnation as appears to be the case in south Slav societies generally, and Macedonian in particular, this is not automatically mirrored in gender relations between men and women. In short, there is a long leap from patriliny to patriarchy.     

Cultural factor in the geographic distribution of personal names: pseudogenetic analysis of first names used to estimate the cultural component of coefficients of relationship by isonymy

By applying to given names formulations for analyzing the genetics of surname distributions, under certain assumptions one can separate the genetic components from the cultural components of surname distributions. Geographic distributions of surnames regularly yield larger coefficients of relationship or kinship within local populations than between them: for instance, Ri = 75 x 10(-5) within a local area in England but the Ri of those villages with all of England and Wales is 42 x 10(-5). On the contrary, the first names in an English and Welsh sample give essentially the same pseudocoefficient (based on first names) within registration districts (Ri = 354 x 10(-5) as between districts (Ri = 370 x 10(-5). Thus the decrease with distance of the coefficients based on surnames can be ascribed to the genetic component according to the Malécot principle, assuming that the first names are chosen in the same way as the surnames originated and consequently that the cultural component of surname distributions is no more localized than the distribution of given names (in this sample not at all).     

Comparison of two Venezuelan populations using the coefficient of relationship by isonymy

The coefficient of relationship by isonymy Ri is a good indicator of similarities between and within populations by means of identity of surnames. In this study we present the results of an analysis of Ri obtained using two surnames for each person in two small Venezuelan populations of African origin: Birongo and La Sabana. The analyses of six Ri values within each population in two periods and of sixteen Ri values within each population between two periods and within each period between populations show that the higher values of Ri are those that include combinations of maternal surnames compared with any other combination and that in one period the relationship between Birongo and La Sabana was equal to 0, as measured with combinations of paternal surnames. These facts are indicators of a tendency toward matrifocal behavior and show that the use of four surnames for estimating Ri permits detailed comparisons of the relationship between and within groups.     

Descent Group Composition and Population Pressure in a Fringe Enga Clan, Papua New Guinea

Genealogical data, land clearance patterns, and garden inheritance histories from a patrilineal clan in the Highlands of Papua New Guinea are used to reconstruct population size and agrarian resources for the descent group over a period of 170 years. The resulting analysis reveals a strong relationship between fluctuations in population pressure on agrarian resources and changes in the composition of social groups that in turn accelerates change, then regulates it. Two quantitative relationships show that numbers of outsiders incorporated into the group and their kinship distance both covary closely with pressure on land as measured by an occupational density index.     

Ethnicity and biodemographic structure in the Arbëreshe of the province of Cosenza, southern Italy, in the XIX century

Cultural and environmental factors interact in determining the genetic structure of human populations. Bio-demographic investigations of ethnic minorities are able to disentangle the influences that these two components have on the evolution of the genetic structure of a population. The ethnic minority of the Arb?reshe of the province of Cosenza (Calabria, southern Italy) is analyzed in this paper and its bio-demographic structure in the early 1800s is compared with that of neighboring Italian populations. The data derive from surnames recorded in the birth registers of the 19 Arbdreshe municipalities of the province of Cosenza and in 5 non-Arb?reshe municipalities of the same province. Isonymy and repeated pairs of surnames are used to analyze the bio-demographic structure of these populations, while analysis of isonymic relationships is used to investigate the variability between populations. Higher values of marital isonymy and subdivision into subpopulations characterize the Arb?reshe populations with respect to their non-Arb?reshe neighbors. However, the high range of variability of these parameters suggests a strong influence of geographic location on the marriage pattern of each community. At the same time, cultural differences linked to group identity had a strong impact in limiting marriage exchanges between the different ethnic groups living in the province of Cosenza in the early 1800s. In fact, the analysis of isonymic relationships demonstrates that geographic location shaped kinship patterns among the Arbereshe communities, but it also shows that the non-Arb?reshe neighbors formed a clearly separate reproductive cluster.     

Genetic signatures of coancestry within surnames

Surnames are cultural markers of shared ancestry within human populations. The Y chromosome, like many surnames, is paternally inherited, so men sharing surnames might be expected to share similar Y chromosomes as a signature of coancestry. Such a relationship could be used to connect branches of family trees, to validate population genetic studies based on isonymy, and to predict surname from crime-scene samples in forensics. However, the link may be weak or absent due to multiple independent founders for many names, adoptions, name changes and nonpaternities, and mutation of Y haplotypes. Here, rather than focusing on a single name, we take a general approach by seeking evidence for a link in a sample of 150 randomly ascertained pairs of males who each share a British surname. We show that sharing a surname significantly elevates the probability of sharing a Y-chromosomal haplotype and that this probability increases as surname frequency decreases. Within our sample, we estimate that up to 24% of pairs share recent ancestry and that a large surname-based forensic database might contribute to the intelligence-led investigation of up to approximately 70 rapes and murders per year in the UK. This approach would be applicable to any society that uses patrilineal surnames of reasonable time-depth.     

Genetic structure of the Utah Mormons: isonymy analysis

Isonymy analysis is reported for a sample of 188,895 marriages extracted from the Utah Genealogical Database. Inbreeding rates estimated by isonymy are low, ranging from 0.005 for the earliest marriage cohort (1800-1809) to 0.0008 in the most recent cohort (1950-1959). The inbreeding values decrease considerably through time, but they are consistently higher than inbreeding values estimated from pedigrees. Several explanations are offered for this, including polyphyletism of surnames and the presence of Scandinavian patronyms in this population. Random isonymy between subdivisions is also compared with random kinship estimated from migration matrices. In terms of within-subdivision kinship, the two approaches yield similar results. However, the results are quite dissimilar for between-subdivision kinship. This reflects the recent and nonrandom settlement of Utah by different ethnic groups with different surname distributions. In later time periods, the correlations between the two types of kinship estimates increase, showing that migration patterns (which are strongly determined by geographic distance) exert an increasing influence on the distribution of surnames. Logistic regression is performed on a subset of marriages (n = 88,202), using isonymous vs. nonisonymous marriage as the dependent variable. The independent variables are year of marriage, geographic distance between husband's and wife's birthplaces, endogamous vs. exogamous marriage, and population sizes of husband's and wife's birthplaces. Year of marriage and geographic distance are shown to be significant independent predictors of isonymous marriage.     

Isonymous structure in the white population of Córdoba, Argentina, in 1813

Surnames analysis is useful for populations in which only written documents remain, as is the case for historical populations. In Córdoba province, Argentina, census records contain nominal data of inhabitants, including information on sex, age, ethnosocial category, civil status, occupation, place of birth, and residence, that can be analyzed using surnames. Relationship indicators within and among ecclesiastic units in Córdoba were estimated by isonymy for the adult white population registered in the 1813 census. The Rii, Rij, and R(ST) coefficients and the surname abundance indicator (a) were calculated. Lasker's distances among categories of population units were used to cluster the 16 provincial population categories. Gradients for kinship within population and for surname diversity were in agreement with the principal areas and waves of original settlement in the province. The main population clusters reflect those areas, whereas minor clusters coincide with the network of roads existing in the territory by 1813. The structure of the white population in Córdoba province was determined by the geographic location of the original waves of settlement, and it followed a pattern of relationships conditioned by the routes connecting population units in the Colonial period.