Long-distance dispersal, ice sheet dynamics and mountaintop isolation underlie the genetic structure of glacier ice worms

Scott Hotaling, Daniel H. Shain, Shirley A. Lang, Robin K. Bagley, Lusha M. Tronstad, David W. Weisrock, Joanna L. Kelley

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Disentangling the contemporary and historical factors underlying the spatial distributions of species is a central goal of biogeography. For species with broad distributions but little capacity to actively disperse, disconnected geographical distributions highlight the potential influence of passive, long-distance dispersal (LDD) on their evolutionary histories. However, dispersal alone cannot completely account for the biogeography of any species, and other factors-e.g. habitat suitability, life history-must also be considered. North American ice worms (Mesenchytraeus solifugus) are ice-obligate annelids that inhabit coastal glaciers from Oregon to Alaska. Previous studies identified a complex biogeographic history for ice worms, with evidence for genetic isolation, unexpectedly close relationships among geographically disjunct lineages, and contemporary migration across large (e.g. greater than 1500 km) areas of unsuitable habitat. In this study, we analysed genome-scale sequence data for individuals from most of the known ice worm range. We found clear support for divergence between populations along the Pacific Coast and the inland flanks of the Coast Mountains (mean FST ¼ 0.60), likely precipitated by episodic ice sheet expansion and contraction during the Pleistocene. We also found support for LDD of ice worms from Alaska to Vancouver Island, perhaps mediated by migrating birds. Our results highlight the power of genomic data for disentangling complex biogeographic patterns, including the presence of LDD.

Original languageEnglish
Article number20190983
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1905
StatePublished - Jun 26 2019

Bibliographical note

Publisher Copyright:
© 2019 The Author(s) Published by the Royal Society. All rights reserved.


  • Annelid
  • Global change biology
  • Mesenchytraeus solifugus
  • Pacific Northwest
  • Phylogeography
  • Restriction-site-associated DNA sequencing

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology
  • General Environmental Science
  • General Agricultural and Biological Sciences


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