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.