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

Abstract

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.

General Method to Unravel Ancient Population Structures through Surnames, Final Validation on Italian Data

“…More recently and in the frame of molecular studies focused on the variability of the Y-chromosome, the study of surnames gained new prominence and has been advocated to design more careful sampling strategies (Boattini et al 2010;Manni et al 2005). Nowadays the technological constraints related to DNA typing are becoming negligible, thus allowing more energy for a meticulous collection of the samples.…”

“…To overcome this limitation, Manni et al (2005) introduced a general surname method (General Method) providing a fast and efficient identification of those geographical areas that remained genetically closer to their past genetic makeup: in other words where immigration has been less intense. When studies about past DNA variability are undertaken, this method enables the design of a more efficient Y-chromosome sampling, because donors can be selected according to the geographic origin of their patrilineal ancestor (being such inference limited to the interval spanning from the present to the time of surname introduction).…”

“…When studies about past DNA variability are undertaken, this method enables the design of a more efficient Y-chromosome sampling, because donors can be selected according to the geographic origin of their patrilineal ancestor (being such inference limited to the interval spanning from the present to the time of surname introduction). By using Self-Organizing Maps (SOMs), a clustering technique based on neural networks (Kaski 1997;Kohonen 1982Kohonen , 1984, Manni et al (2005) examined the whole surname body of The Netherlands all at once and without the need of any historical or genealogical insight. This study enabled the identification of groups of surnames sharing the same geographic origin and an identical migration history, allowing the targeting of individuals still living in the area where their surname originated (in other words "autochthonous"-for an application see Manni and Toupance 2010).…”

“…This study enabled the identification of groups of surnames sharing the same geographic origin and an identical migration history, allowing the targeting of individuals still living in the area where their surname originated (in other words "autochthonous"-for an application see Manni and Toupance 2010). Manni et al (2005) suggested that the degree of autochthony can considerably vary from zone to zone, being influenced by geographical and historical factors that result in differential patterns of migration.…”

Hidden African Ancestors: Hidden secrets of your ancestors

“…4 It has even been shown that in the ideal case population substructure can be inferred only on the basis of detailed surname analyses. 5 Although this might be true in general, in isolated cases false paternity or in vitro fertilization by means of anonymous sperm donors disrupts the link between a particular surname and its corresponding Y-chromosomal genotype. Of course, also a perfectly legal marriage can introduce 'exotic' Y-chromosomes into a pedigree.…”