Reindeer from Sámi offering sites document the replacement of wild reindeer genetic lineages by domestic ones in Northern Finland starting from 1400 to 1600 AD

•Ancient reindeer from Sámi offering and dwelling sites are genetically similar.•Replacement of wild reindeer haplotypes starting from 1400–1600 AD.•Finland not the birthplace of large-scale reindeer pastoralism in Fennoscandia.•The transition to reindeer herding affected ritual practices of the Sámi.