Historical and social–cultural processes as drivers for genetic structure in Nordic domestic reindeer

Knut H Røed,Bård‐J Bårdsen,Kjell‐Å Aronsson,Sauli Laaksonen,Birgitta Åhman,Hannes Lohi,Kjersti S Kvie,Jørn Våge,Jouko Kumpula,Øystein Holand

doi:10.1002/ece3.7728

Abstract

AbstractWe have analyzed DNA microsatellites and the mitochondrial control region in reindeer from 31 different husbandry areas in Norway, Sweden, and Finland in order to better understand the processes that underlie the genetic variability of the Nordic domestic herds. The distinct differentiation found in the nuclear markers but less so in the mitochondrial marker gives evidence of an origin from a common ancestral population which later evolved into the two main gene pools characterizing the nuclear genomes of domestic reindeer in Finland and most of Sweden and Norway. Analyses of temporal trends in effective population size give evidence of a rapid increase in number of reindeer before the population growth associated with the pastoral transition. This implies that the ancestry of contemporary domestic reindeer lay among a rapidly growing wild population possibly located in the boreal areas of eastern Fennoscandia or European Russia. The evolution of reindeer husbandry in Finland, perhaps with input from European Russia, which later spread to northern Norway could explain the shared genomic pattern observed in these areas today. The structured selection of productive female‐centered herds may explain the genetic structure in other parts of Norway and in Sweden. The further substructuring of the Swedish/ Norwegian gene pool appears to follow the traditional language borders with the South Sámi language dominating the southern and the Central Sámi language in the more northern genetic subclusters. This suggests that traditional knowledge, cultural identities, and herd migrations have contributed to shape the genetic structure seen today. Ecological gradients are more pronounced within as compared to between the genetic clusters, giving further evidence that historical and social–cultural processes are important drivers for the genetic differentiations found in domestic reindeer across the Nordic countries.

Highlights

Domestication of reindeer, Rangifer tarandus, and the emergence of large-scaled reindeer herding laid the foundation for one of the most fundamental social transformations that has occurred in Circumpolar North (Hansen & Olsen, 2014; Krupnik, 1993)
Selection, and improvement of reindeer husbandry are dependent on the genetic variability that exists in the animal resources (FAO, 2007, 2015; Groeneveld et al, 2010)
Arlequin v3.5 was used to estimate pairwise genetic differentiation using the FST values (Weir & Cockerham, 1984) and to perform a Mantel as described above for the mitochondrial DNA (mtDNA) data, Genetic structuring of microsatellite variation at an individual level was analyzed in the software STRUCTURE (Pritchard et al, 2000) based on the admixture model, correlated allele frequencies, no a priori group membership, 30,000 burn-in cycles, and 300,000 MCMC iterations

Summary

| INTRODUCTION

Domestication of reindeer, Rangifer tarandus, and the emergence of large-scaled reindeer herding laid the foundation for one of the most fundamental social transformations that has occurred in Circumpolar North (Hansen & Olsen, 2014; Krupnik, 1993). The Nordic reindeer husbandry is a highly diverse social– ecological system, which in the case of Sámis evolved as an adaption to natural conditions, history, competing land use, and legal rights (Holand et al, 2021; Käyhkö & Hortskotter, 2017; Manker, 1953) Their traditional nomadic herding systems range from alpine tundra forms characterized by long seasonal migrations frequently found in northern Norway and Sweden, to coastal forms, with local seasonal migrations found in mid-part of Norway, and taiga forms typically seen in Sweden and Finland with year- around grazing in the forest zone confined to relatively small areas (Manker, 1953, 1968; Riseth et al, 2018). Herds with seasonal migration using the Alpine region most of the year but straying partly within the Boreal region during winter (area 18 and 20) were classified to the Alpine region

| Laboratory methods

| MATERIAL AND METHODS

Findings

| DISCUSSION