Holarctic genetic structure and range dynamics in the woolly mammoth

Eleftheria Palkopoulou,Love Dalén,Jessica A Thomas,Mikhail Sablin,Ian Barnes,Andrei Sher,Mikael D Brandström,Sergey Vartanyan,Adrian M Lister,Veronica Nyström Edmark,Mietje Germonpré

doi:10.1098/rspb.2013.1910

Abstract

Ancient DNA analyses have provided enhanced resolution of population histories in many Pleistocene taxa. However, most studies are spatially restricted, making inference of species-level biogeographic histories difficult. Here, we analyse mitochondrial DNA (mtDNA) variation in the woolly mammoth from across its Holarctic range to reconstruct its history over the last 200 thousand years (kyr). We identify a previously undocumented major mtDNA lineage in Europe, which was replaced by another major mtDNA lineage 32–34 kyr before present (BP). Coalescent simulations provide support for demographic expansions at approximately 121 kyr BP, suggesting that the previous interglacial was an important driver for demography and intraspecific genetic divergence. Furthermore, our results suggest an expansion into Eurasia from America around 66 kyr BP, coinciding with the first exposure of the Bering Land Bridge during the Late Pleistocene. Bayesian inference indicates Late Pleistocene demographic stability until 20–15 kyr BP, when a severe population size decline occurred.

Highlights

One of the greatest strengths of an ancient DNA approach is that it enables the study of genetic change through time
Our results suggest an expansion into Eurasia from America around 66 kyr before present (BP), coinciding with the first exposure of the Bering Land Bridge during the Late Pleistocene
The last interglacial, known in Europe as the Eemian and equated with MIS 5e (130– 116 kyr BP), was a period characterized by climate at least as warm as today [42]

Summary

Introduction

One of the greatest strengths of an ancient DNA (aDNA) approach is that it enables the study of genetic change through time. Analyses of samples across particular geographical regions through time have revealed unexpected patterns of local population extinction and recolonization [1,2,3,4,5,6] While such studies are invaluable for investigating the interaction between population dynamics and local changes in the environment, it is not always clear how different lineages evolved and where recolonizing populations originated. We extract and analyse mtDNA from woolly mammoth specimens from across the Holarctic, expanding the genetic sampling both spatially and temporally. Combined with previously published mtDNA sequences, the dataset comprises more than 300 mammoth specimens, enabling a thorough reconstruction of the species’ population history from the Late Middle Pleistocene (LMP) up until its extinction. BEAST analyses were run under three different population models, for 200 million generations and sampled every 20 000. Uniform priors were used for Nef, split time and migration rate (for details, see the electronic supplementary material, figure S2)

Results

Discussion

Campos PF et al 2010 Ancient DNA analyses

Edwards Ceiridwen J et al 2011 Ancient

Findings

11. Debruyne R et al 2008 Out of America: ancient DNA