Comparisons of Lasker's coefficient of relationship in a Venezuelan town in two different periods

Isonymy structure of USA population

The isonymy structure of the 48 states of the continental United States of America was studied using the surname distributions of 18 million telephone users, distributed in 247 towns. The shortest linear distance between nearest neighbor towns included in the sample was 12.0 km. The largest distance was 4,577 km. The number of different surnames found in the whole analysis was 899,585. Lasker's distance was found to be significantly but weakly correlated with the geographic distance, with r = 0.21 +/- 0.01. A dendrogram of the 48 states was built from the matrix of isonymy distances: it divides the US into several clusters, in general correlated with geography. A notable exception is California and New Jersey, which cluster together. Wisconsin is separated from all other states. An important cluster is formed by Texas, Colorado, New Mexico, Nevada, and Arizona, together with Illinois and Florida. It was observed that Hispanic surnames are among the most frequent in Illinois, as they are in New Jersey and California. No main distinction among the states clearly attributable to surnames of French origin was detected; however, New Hampshire, Vermont, and Maine which have a considerable number of these surnames belong to the same northeastern cluster. From the present analysis, the great mobility of the US population emerges clearly, and it seems relevant that the practical absence of isolation by distance is seen also considering only small towns. It appears that groups of different origin are well-mixed over the whole area of the United States. The values of isonymy indicate that the south-central area of the USA has the highest level of inbreeding. In fact, the heterogeneity in surname composition is greater in the coastal areas, particularly on the East Coast, than anywhere else in the USA.

Elements of the surname structure of Austria

The isonymy structure of Austria was studied using the surname distributions in 1081002 private telephone users selected from about 4000000 registered in a 1996 commercial CD-ROM, which contains all Austrian users. The sample was distributed in 120 towns representing an approximately uniform distribution over the country. The number of different surnames found in the whole analysis was 140766. Lasker's distance, the negative value of the logarithm of isonymy between localities, was found to be linearly and significantly correlated with the log of geographic distance, with r = 0.565 +/- 0.011. A dendrogram was built with the matrix of isonymy distance, using the Unweighted Pair-Group Method using Arithmetic averages, UPGMA. It separates the Austrian towns in five main clusters, one along the central portion of the country, another one which occupies the northern region of central Austria; then comes a third cluster at the north-eastern part, a fourth cluster in the western region, and finally a small cluster towards the border with Slovenia. Within each, small subclusters with specific geographic distributions could be delimited. The main clusters correspond fairly well to the classic regions of Austria. The results were compared with those obtained in similar analyses of Switzerland, Germany, Italy and Venezuela. From the present analysis, isolation by distance emerges clearly, and it is stronger than in Germany but smaller than that observed in Italy, Switzerland and Venezuela. The random component of inbreeding estimated from isonymy, at the level of resolution used here, indicates that the inbreeding level in Austria is rather uniform.

Isonymy and the genetic structure of Switzerland. I. The distributions of surnames

The surname distribution of the population of Switzerland was studied using a sample of 1,702,000 private users registered for the year 1994 in the Helvetic Telephone Directory. These users were distributed in four linguistic areas, in 26 Cantons and 271 Communes of the Confederation. Estimates of unbiased random isonymy, of Fisher's alpha, an indicator of abundance of surnames converging to the allele effective number in standard genetic polymorphisms, and of Karlin-McGregor's v, an indicator of immigration rates, were calculated for each Commune, each Canton, each linguistic area and for the whole Confederation. The Commune with the highest value of alpha was Geneva (alpha = 5312) followed by Versoix (3713) and by the Communes of Vaud on the north shore of Lake Leman, Chavannes (3381), Montreux (3200), Nyon (3114) and Lausanne (3109). The Italian-speaking Communes of the Ticino were next. The lowest value (alpha = 29) was observed in Poschiavo, south of the Berninapass; alpha = 39 was observed in Einsiedeln (Schwyz); then Mels and Widnau (62 and 67, Canton of St Gallen), Frutingen in Bern (72), and Appenzell (80). Accordingly, the highest consanguinity values were observed in the Grisons and in the nucleus of the founding Cantons, while the lowest were observed in the Cantons of Geneva and Vaud, preferential areas of immigration to Switzerland from abroad. The effect of subdivision on isonymy is large at the Commune level, and decreases in Cantons and linguistic groups. French and Italian languages indicate minor, German and Romanisch major inbreeding.

Microevolution in Perugia: isonymy 1890-1990

The distribution of surnames in the population of the Comune of Perugia, as it existed in the memory banks of the Municipality Computer in autumn 1991, was studied by age and place of birth. Fisher's alpha and Karlin-McGregor's v were estimated in the total population, in persons born before 1901, and in persons born in the nine decades thereafter, ending with the period 1981-1991, for immigrants and for natives of Perugia, respectively. The wealth of surnames was significantly higher in immigrants than in natives of Perugia, as detected by alpha, v and by the log-log regression of the corresponding distributions. Among residents born in Perugia, Fisher's alpha shows a minimum value during 1921-1930, explained as a consequence of the First World War. The relationship between all possible combinations of cohorts born in the 10 different decades was studied through the Euclidean distance and through Lasker's coefficient of relationship, and a significant correlation between the former and time was revealed, both in immigrants and in natives of Perugia. When compared with the Province of Ferrara, Perugia was far richer in surnames, as measured by Fisher's alpha, for the total population and for each of the 10 decades analysed. Recent immigration, measured by Karlin-McGregor's v, was significantly higher in Perugia until the 1960s, equal in both Provinces during the 1970s, and higher in Ferrara during the 1980s.

Isonymy structure of four Venezuelan states

The isonymy structure of four Venezuelan States-Falcón, Mérida, Nueva Esparta and Yaracuy-was studied using the surnames of the Venezuelan register of electors updated in 1984. The surname distributions of 155 counties were obtained and, for each county, estimates of consanguinity due to random isonymy and Fisher's alpha were calculated. It was shown that for large sample sizes the inverse of Fisher's alpha is identical to the unbiased estimate of within-population random isonymy. A three-dimensional isometric surface plot was obtained for each State, based on the counties' random isonymy estimates. The highest estimates of random consanguinity were found in the States of Nueva Esparta and Mérida, while the lowest were found in Yaracuy. Other microdifferentiation indicators from the same data gave similar results, and an interpretation was attempted, based on the particular economic and geographic characteristics of each State. Four different genetic distances between all possible pairs of counties were calculated within States; geographic distance shows the highest correlations with random isonymy and Euclidean distance, with the exception of the State of Nueva Esparta, where there is no correlation between geographic distance and random isonymy. It was possible to group counties in clusters, from dendrograms based on Euclidean distance. Isonymy clustering was also consistent with socioeconomic and geographic characteristics of the counties.

Genetic distance estimated through surname frequencies of 37 counties from the state of Lara, Venezuela

Genetic distances between all possible pairs of counties (n = 37) in the state of Lara, Venezuela were calculated using surname frequencies and the Euclidean distance as estimator. In general, Euclidean distances were smaller between counties closer together, and the product moment correlation between geographic and Euclidean distances was 0.49 (p < 0.02). The results suggest that, in Lara, geographic distance has been an important determinant of genetic structure, although topography and roadways also have had an important influence upon this structure.

Microevolution in Ferrara: isonymy 1890-1990

The distribution of surnames in the population of the town of Ferrara, as it existed in the memory banks of the Municipality Computer in June 1990, was studied by sex, age and place of birth of residents. Random isonymy was studied separately in persons born before 1901, and in persons born in the nine decades thereafter, ending with the period 1981-90. Isonymy was higher in the older age groups studied. Also other indicators of the abundance of surnames in the distribution, the common ecological indexes derived from entropy, were calculated and compared between age groups. It was found that redundancy, as isonymy, is larger in older age classes than in younger classes. Surname effective number was defined as the inverse of isonymy corrected for sample size, and it was observed that it is practically identical with Fisher's alpha. It was then possible to separate random isonymy into two components, so that for sample size N its formulation becomes Ir = 1/alpha + 1/N It was found that in Ferrara alpha increased significantly in time, indicating enrichment of surnames in the population in the century 1890-1990.

Isonymy in records of births and deaths in Ferrara

Surname distributions were studied in records of male and female births in Ferrara in the period 1982-89, and in records of male and female deaths in the same period. Average year of birth and standard deviation was 1985 +/- 2.3 for the birth series, and 1912 +/- 14.4 for the death series. Then the surname distributions, in two independent samples at an average distance of 73 years, were compared. It was observed that random isonymy within series, which depends on the shape of the distribution, stays fairly constant at three generations of distance, indicating near-equilibrium of surname turnover. The migrational contribution is indicated by the significant decrease of random isonymy between series, measured with the method of Lasker. It was also observed that immigrants to Ferrara have a life-span significantly longer than people born in the town.