Origins of Aleuts and the genetic structure of populations of the archipelago: molecular and archaeological perspectives

We summarize the results of a field and laboratory research program (1999-2006) in the Aleutian Islands on the origins of the inhabitants of the archipelago and the genetic structure of these populations. The Aleuts show closest genetic affinity to the contemporary Siberian Eskimos and Chukchi of Chukotka and differ significantly from the populations of Kamchatka (the terminus of the archipelago) and Alaskan Eskimos. Our findings support the hypothesis that the ancestors of the Aleuts crossed Beringia and expanded westerly into the islands approximately 9,000 years ago. The Monmonier algorithm indicates genetic discontinuity between contemporary Kamchatkan populations and western Aleut populations, suggesting that island hopping from Kamchatka into the western Aleutian Islands was highly unlikely. The primary determinant of the distribution of genes throughout the archipelago is geography. The most intimate relationship exists between the genetics (based on mtDNA sequences and intermatch/mismatch distances) and geographic distances (measured in kilometers). However, the Y-chromosome haplogroup frequencies are not significantly correlated with the geography of the Aleutian Islands. The underlying patterns of precontact genetic structure based on Y-chromosome markers of the Aleut populations is obscured because of the gene flow from Russian male colonizers and Scandinavian and English fishermen. We consider alternative theories about the peopling of the Americas from Siberia. In addition, we attempt a synthesis between archaeological and genetic data for the Aleutian Islands.     

South from Alaska: a pilot aDNA study of genetic history on the Alaska Peninsula and the eastern Aleutians

The Aleutian Islands were colonized, perhaps several times, from the Alaskan mainland. Earlier work documented transitions in the relative frequencies of mtDNA haplogroups over time, but little is known about potential source populations for prehistoric Aleut migrants. As part of a pilot investigation, we sequenced the mtDNA first hypervariable region (HVRI) in samples from two archaeological sites on the Alaska Peninsula (the Hot Springs site near Port Moller, Alaska; and samples from a cluster of sites in the Brooks River area near Katmai National Park and Preserve) and one site from Prince William Sound (Mink Island). The sequences revealed not only the mtDNA haplogroups typically found in both ancient and modern Aleut populations (A2 and D2) but also haplogroups B2 and D1 in the Brooks River samples and haplogroup D3 in one Mink Islander. These preliminary results suggest greater mtDNA diversity in prehistoric populations than previously observed and facilitate reconstruction of migration scenarios from the peninsula into the Aleutian archipelago in the past.     

Genetic architecture of a small, recently aggregated Aleut population: Bering Island, Russia

The fishing community of Bering Island, located in the Russian Commander Islands off the Kamchatka Peninsula, was originally founded by a small number of Russian soldiers and merchants, along with Aleuts forcibly relocated from the western region of the Aleutian archipelago. The purpose of this study is to characterize the genetic variation of Bering Island inhabitants for autosomal, mitochondrial, and Y-chromosome DNA and classic genetic markers and to investigate the genetic impact of the 19th-century founding and subsequent demographic events on this heterogeneous community. Our results show a loss of diversity among maternal lineages in the Bering Aleut population, with fixation of mtDNA haplogroup D, as revealed by median-joining network analysis and mismatch differences. Conversely, paternal haplotypes exhibit an increase in diversity and the presence of a substantial number of non-Native lineages. Admixture results, based on autosomal STR data, indicate that parental contributions to the mixed Aleut population of Bering are approximately 60% Aleut and 40% Russian. Classic genetic markers show affinities between the Bering Island Aleuts and the other historically founded Aleut communities of St. Paul and St. George in the Pribilof Islands, Alaska. This study demonstrates that the opposing evolutionary forces of genetic drift and gene flow acted on the maternal and paternal lineages, respectively, to shape the genetic structure of the present-day inhabitants of Bering Island.     

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.     

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.     

Namesakes or relatives? Approaches to investigating the relationship between Y chromosomal haplogroups and surnames

Population genetics successfully applies surnames as quasi-genetic markers when estimating similarity between populations and calculating a measure of random inbreeding. These calculations are based on an isonomy coefficient which assumes that every surname is monophyletic: that it originated from single common ancestor and all namesakes are therefore relatives. On the other hand, there is a general opinion that a typical Russian surname is polyphyletic: it originated multiple times and most namesakes are therefore not related to each other. Combined studies of Y chromosomes and surnames now allow us to address this issue. In this study, we discuss approaches for statistical evaluation of Y chromosomal haplogroup frequencies in groups of people bearing the same surname (namesakes). We propose an 'Index of Accumulated Haplogroup Frequency', which allows for errors due to random (artifactual) effects increasing a haplogroup frequency in a group of namesakes by subtracting the population frequency of this haplogroup. This population frequency is calculated as the weighted average of the frequencies of this haplogroup in the populations that the carriers of this surname come from. Fom the total sample (comprising 1244 persons from 13 populations of the historical Russian area) we chose 123 persons carrying 14 surnames which were the most frequent in the total sample. Haplogroup frequencies in these 14 "surname" groups were compared with the respective 14 "population" control groups compiled from the total sample as described above. We found that even these widespread surnames exhibit non-random accumulation of specific Y chromosomal haplogroups. More detailed analyses of the relationships between namesakes could be carried out using Y-STR haplotypes rather than Y-SNP haplogroups, and will be the subject of a future study.     

Namesakes or relatives? Approaches to investigating the relationship between Y chromosome haplogroups and surnames

Population genetics successfully applies surnames as quasi-genetic markers when estimating similarity between populations and calculating the level of random inbreeding. These calculations are based on the isonymy coefficient, which assumes that every surname is monophyletic, i.e., it originated from a single common ancestor and all namesakes are therefore relatives. On the other hand, there is a general opinion that a typical Russian surname is polyphyletic: it originated multiple times and most namesakes are, therefore, not related to each other. Combined studies of Y chromosomes and surnames now allow us to address this issue. This study discusses approaches to statistical evaluation of Y chromosome haplogroup frequencies in groups of people bearing the same surname (namesakes). The proposed index of accumulated haplogroup frequency eliminates the artifactual effect of a randomly increased haplogroup frequency in namesakes by subtracting its population (expected) frequency from the observed value, while the expected frequency is calculated as the weighted average of the frequencies of this haplogroup in the populations where the surname carriers come from. From the total sample (comprising 1244 persons from 13 populations of the historical Russian area), 123 individuals carrying 14 most frequent surnames were chosen. A comparison of the haplogroup frequencies in these 14 namesake groups and in 14 respective population control groups compiled from the total sample showed that accumulation of certain Y chromosome haplogroups was nonrandom even in carriers of widespread surnames. An analysis of Y-STR haplotypes rather than Y-SNP haplogroups could provide a better insight into relationships between namesakes and will be the subject of further research.     

Surnames and the Y chromosome

A randomly ascertained sample of males with the surname "Sykes" was typed with four Y-chromosome microsatellites. Almost half the sample shared the same Y-chromosome haplotype, which has not been observed in control samples either from the same geographic region or from the United Kingdom as a whole. This points to a single surname founder for extant Sykes males, even though written sources had predicted multiple origins. The distribution of other Sykes Y-chromosome haplotypes were not significantly different from those in controls and may be accounted for by the historical accumulation of nonpaternity during the past 700 years, in which case the average rate estimate is 1.3%/generation. If this pattern is reproduced with other surnames, it may have important forensic and genealogical applications.     

Gene pool structure of Russian populations from the European part of Russia inferred from the data on Y chromosome haplogroups distribution

Population structure of Russian population from the European part of Russia was investigated by analyzing the distribution of 23 SNP makers of Y chromosome in Russian populations from Kaluga oblast, Yaroslavl' oblast, Vladimir oblast, Nizhny Novgorod oblast, Pskov oblast, Tula oblast, Belgorod oblast, and Novgorod oblast. In the populations studied a total of 14 Y-chromosome haplogroups (E, F*, I, J, K*, N3a, N2, P*, R1*, R1a1, C3, H, and A) were discovered, of which haplogroups R1a1, I, and N3a were the prevailing. Analysis of Phi statistics in the populations grouped in accordance to the dialect subdivision of the Russian language, showed the absence of statistically significant differences between Russian population groups. Analysis of the Y-chromosome markers distribution patterns among Russian population (10 population groups) in comparison with the population of Germany (11 population groups) revealed statistically significant differences between the gene pools of Slavs (Russians and Poles) and Teutons (Germans).     

Gene pool structure of Russian populations from the European part of Russia inferred from the data on Y chromosome haplogroups distribution

Population structure of Russian population from the European part of Russia was investigated by analyzing the distribution of 23 SNP makers of Y chromosome in Russian populations from Kaluga, Yaroslavl’, Vladimir, Nizhni Novgorod, Pskov, Tula, Belgorod, and Novgorod oblasts. In the populations studied a total of 14 Y-chromosome haplogroups (E, F*, I, J, K*, N3a, N2, P*, R1*, R1a1, C3, G, H, and A) were discovered, of which haplogroups R1a1, I, and N3a were the prevailing. Analysis of Φ statistics in the populations grouped in accordance to the dialect subdivision of the Russian language, showed the absence of statistically significant differences between Russian population groups. Analysis of the Y-chromosome markers distribution patterns among Russian population (10 population groups) in comparison with the population of Germany (11 population groups) and Poland (8 population groups) revealed statistically significant differences between the gene pools of Slavs (Russians and Poles) and Teutons (Germans).     

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.     

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]     

Genetics in genealogical research--reconstruction of a family tree by means of Y-haplotyping

In societies, in which surnames are inherited patrilinearly, surnames and certain Y-chromosome STR allelic patterns, so-called Y-haplotypes, correlate. In order to reconstruct the relationship between three different family lines with the surname Zierdt, a total of 34 German and US-American males with this surname was selected. Among those test candidates several family branches could be identified on the basis of written records. However, the relationship between those family lines was as yet unknown as the necessary documents had not been available. By haplotyping in two family lines the same Y-haplotype could be recognised, thus belonging to the same paternal lineage. As the third family line revealed a deviant Y-haplotype, its relationship could be excluded. Four cases of non-paternity could be revealed and put into historical context.     

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.     

Portuguese migration to the Canary Islands: an analysis based on surnames

As a part of a wider analysis of population and genetic exchange between Spain and Portugal, the long-term pattern of Portuguese immigration to the Canary Islands was studied by means of the frequency of Portuguese surnames. A database of 1,995,833 individuals was obtained from the Spanish National Statistics Institute (2006). Among the 826 most frequent surnames to appear, 79 surnames of Portuguese origin were selected. The distribution of these surnames by municipalities and islands, the Fisher index of diversity, and the Lasker inter-population relationship coefficients R(ij) were considered. These coefficients were inter-correlated and correlated with other variables that could have influenced the distribution of surnames. From the observed distribution of the frequency of surnames, a non-random migration pattern conditioned by economic factors was found. The greatest diversity of surnames existed in cane cultivating areas after the first arrival of Portuguese immigrants. A later dispersion of surnames among islands was correlated with the inter-island geographic distances. In some islands the arrival of new immigrants continued due to their strategic location within the Canary archipelago. The Canary Islands reveal a high frequency and diversity of Portuguese surnames. The results also prove a heterogeneous distribution of these surnames throughout the archipelago. In contrast to the Portuguese archipelagos, some Canary localities have received immigrants continuously because of their economic importance in sugar cane cultivation and strategic geographic location on the maritime routes to Africa and America.     

Y-chromosome variation among Sudanese: restricted gene flow, concordance with language, geography, and history

We study the major levels of Y-chromosome haplogroup variation in 15 Sudanese populations by typing major Y-haplogroups in 445 unrelated males representing the three linguistic families in Sudan. Our analysis shows Sudanese populations fall into haplogroups A, B, E, F, I, J, K, and R in frequencies of 16.9, 7.9, 34.4, 3.1, 1.3, 22.5, 0.9, and 13% respectively. Haplogroups A, B, and E occur mainly in Nilo-Saharan speaking groups including Nilotics, Fur, Borgu, and Masalit; whereas haplogroups F, I, J, K, and R are more frequent among Afro-Asiatic speaking groups including Arabs, Beja, Copts, and Hausa, and Niger-Congo speakers from the Fulani ethnic group. Mantel tests reveal a strong correlation between genetic and linguistic structures (r = 0.31, P = 0.007), and a similar correlation between genetic and geographic distances (r = 0.29, P = 0.025) that appears after removing nomadic pastoralists of no known geographic locality from the analysis. The bulk of genetic diversity appears to be a consequence of recent migrations and demographic events mainly from Asia and Europe, evident in a higher migration rate for speakers of Afro-Asiatic as compared with the Nilo-Saharan family of languages, and a generally higher effective population size for the former. The data provide insights not only into the history of the Nile Valley, but also in part to the history of Africa and the area of the Sahel.     

Structure of the gene pool of eastern Ukrainians from Y-chromosome haplogroups

Y chromosomes from representative sample of Eastern Ukrainians (94 individuals) were analyzed for composition and frequencies of haplogroups, defined by 11 biallelic loci located in non-recombining part of the chromosome (SRY1532, YAP, 92R7, DYF155S2, 12f2, Tat, M9, M17, M25, M89, and M56). In the Ukrainian gene, pool six haplogroups were revealed: E, F (including G and I), J, N3, P, and R1a1. These haplogroups were earlier detected in a study of Y-chromosome diversity on the territory of Europe as a whole. The major haplogroup in the Ukrainian gene pool, haplogroup R1a1 (earlier designated HG3), accounted for about 44% of all Y chromosomes in the sample examined. This haplogroup is thought to mark the migration patterns of the early Indo-Europeans and is associated with the distribution of the Kurgan archaeological culture. The second major haplogroup is haplogroup F (21.3%), which is a combination of the lineages differing by the time of appearance. Haplogroup P found with the frequency of 9.6%, represents the genetic contribution of the population originating from the ancient autochthonous population of Europe. Haplogroups J and E (11.7 and 4.2%, respectively) mark the migration patterns of the Middle-Eastern agriculturists during the Neolithic. The presence of the N3 lineage (9.6%) is likely explained by a contribution of the assimilated Finno-Ugric tribes. The data on the composition and frequencies of Y-chromosome haplogroups in the sample studied substantially supplement the existing picture of the male lineage distribution in the Eastern Slav population.     

Gene pool of ethnic groups of the caucasus: results of integrated study of the Y chromosome and mitochondrial DNA and genome-wide data

Genetic diversity has been analyzed in 22 ethnic groups of the Caucasus on the basis of data on Y-chromosome and mitochondrial DNA (mtDNA) markers, as well as genome-wide data on autosomal single-nucleotide polymorphisms (SNPs). It has been found that the West Asian component is prevailing in all ethnic groups studied except for Nogays. This Near Eastern ancestral component has proved to be characteristic of Caucasian populations and almost entirely absent in their northern neighbors inhabiting the Eastern European Plain. Turkic-speaking populations, except Nogays, did not exhibit an increased proportion of Eastern Eurasian mtDNA or Y-chromosome haplogroups compared to some Abkhaz-Adyghe populations (Adygs and Kabardians). Genome-wide SNP analysis has also shown substantial differences of Nogays from all other Caucasian populations studied. However, the characteristic difference of Nogays from other populations of the Caucasus seems somewhat ambiguous in terms of the R1a1a-M17(M198) and R1b1b1-M73 haplogroups of the Y chromosome. The state of these haplogroups in Turkic-speaking populations of the Caucasus requires further study.