Temporal differentiation across a West-European Y-chromosomal cline: genealogy as a tool in human population genetics

Abstract

The pattern of population genetic variation and allele frequencies within a species are unstable and are changing over time according to different evolutionary factors. For humans, it is possible to combine detailed patrilineal genealogical records with deep Y-chromosome (Y-chr) genotyping to disentangle signals of historical population genetic structures because of the exponential increase in genetic genealogical data. To test this approach, we studied the temporal pattern of the 'autochthonous' micro-geographical genetic structure in the region of Brabant in Belgium and the Netherlands (Northwest Europe). Genealogical data of 881 individuals from Northwest Europe were collected, from which 634 family trees showed a residence within Brabant for at least one generation. The Y-chr genetic variation of the 634 participants was investigated using 110 Y-SNPs and 38 Y-STRs and linked to particular locations within Brabant on specific time periods based on genealogical records. Significant temporal variation in the Y-chr distribution was detected through a north-south gradient in the frequencies distribution of sub-haplogroup R1b1b2a1 (R-U106), next to an opposite trend for R1b1b2a2g (R-U152). The gradient on R-U106 faded in time and even became totally invisible during the Industrial Revolution in the first half of the nineteenth century. Therefore, genealogical data for at least 200 years are required to study small-scale 'autochthonous' population structure in Western Europe.

High Y-chromosomal diversity and low relatedness between paternal lineages on a communal scale in the Western European Low Countries during the surname establishment

“…The lack of a genetic signature of the specific historical development may suggests that contacts between the Roman and Germanic areas were already intensive before the political end of the Western Roman Empire and that during the decline of the Roman Empire, German groups continued gradually to move south and assimilated homogeneously into whole of Flanders (Lamarcq and Rogge, 1996). Otherwise, if there was after all a genetic signature of the historical development, this must have been faded away at the time of surname establishment on a communal scale owing to the entropy or more recent population-wide migration events (Larmuseau et al, 2012a). Therefore, no indication for a historical admixture event during the Roman Period was observed in this Flemish study to clarify the observed high Y-chromosomal diversity within the communities.…”

“…The 42 (Larmuseau et al, 2012a(Larmuseau et al, , 2014b; this data is accessible on the YHRD (www.yhrd.org) with accession numbers YA003651, YA003652, YA003653, YA003738, YA003739, YA003740, YA003741 and YA003742.…”

“…An optimal Western European region to study the value of this approach on a community level is Flanders (Belgium) owing to its central location, its lack of noteworthy cultural and geographical isolates in the 'open' geography, and the decades-long tradition of performing archaeology, historical population registration and surname studies on a communal and regional scale (Cloet and Vandenbroeke, 1989;Debrabandere, 2003;Barrai et al, 2004). Moreover, the Y-chromosomal diversity at a high phylogenetic resolution is already well known on a regional scale in Flanders which revealed a well-studied historical genetic pattern (Larmuseau et al, 2012a(Larmuseau et al, , 2014b. Also a stable low EPP rate of 1-2% per generation in the last 400 years is observed within Flanders, making the genetic genealogical approach feasible in this region (Larmuseau et al, 2013a).…”

Low historical rates of cuckoldry in a Western European human population traced by Y-chromosome and genealogical data

“…These surnames are known to be introduced only during the past gene flow at the end of the sixteenth century, as reported by Larmuseau et al [44]. To avoid too complex a model, we did not consider the possibility of EPP events from foreign populations into the AFS as this would have had a marginal effect on the population diversity [44,54]. The genetic relationship between the four groups, namely rpAFS, cAFS, rpFRS and cFRS, were assessed by means of Weir & Cockerham's [55] estimate of F ST without taking evolutionary distance between individual subhaplogroups into account.…”

In the name of the migrant father—Analysis of surname origins identifies genetic admixture events undetectable from genealogical records

“…Using concrete genealogical information, one will directly analyze pre-industrial population structure and will quantify the effect of gene flow during the last centuries on population genetic structure (King and Jobling 2009b;Larmuseau et al, 2011). A recent study on the West-European region Brabant found significant temporal differentiation along a north-south gradient based on in-depth genetic-genealogical data (Larmuseau et al, 2012). Generally speaking, a substantial series of genealogical documents are present in Western-European history ever since the beginning of the seventeenth century.…”