The K = 2 conundrum

Jasmine K. Janes, Joshua M. Miller, Julian R. Dupuis, René M. Malenfant, Jamieson C. Gorrell, Catherine I. Cullingham, Rose L. Andrew

Research output: Contribution to journalArticlepeer-review

374 Scopus citations

Abstract

Assessments of population genetic structure have become an increasing focus as they can provide valuable insight into patterns of migration and gene flow.STRUCTURE, the most highly cited of several clustering-based methods, was developed to provide robust estimates without the need for populations to be determined a priori.STRUCTURE introduces the problem of selecting the optimal number of clusters, and as a result, the ΔK method was proposed to assist in the identification of the “true” number of clusters. In our review of 1,264 studies usingSTRUCTURE to explore population subdivision, studies that used ΔK were more likely to identify K = 2 (54%, 443/822) than studies that did not use ΔK (21%, 82/386). A troubling finding was that very few studies performed the hierarchical analysis recommended by the authors of both ΔK andSTRUCTURE to fully explore population subdivision. Furthermore, extensions of earlier simulations indicate that, with a representative number of markers, ΔK frequently identifies K = 2 as the top level of hierarchical structure, even when more subpopulations are present. This review suggests that many studies may have been over-or underestimating population genetic structure; both scenarios have serious consequences, particularly with respect to conservation and management. We recommend publication standards for population structure results so that readers can assess the implications of the results given their own understanding of the species biology.

Original languageEnglish
Pages (from-to)3594-3602
Number of pages9
JournalMolecular Ecology
Volume26
Issue number14
DOIs
StatePublished - Jul 2017

Bibliographical note

Funding Information:
We would like to thank all of the authors of the papers that we reviewed, and Armando Geraldes for prompt communication before and during the submission process. We would also like to thank Bob Verity, Kimberly Gilbert and one anonymous reviewer for their insightful feedback and helpful suggestions during the review process. The lead author’s contribution was funded by ARC Discovery Project DP150103591. Less formal thanks are owed to comfortable couches, doting pets, fine breweries and wineries everywhere, and laser eye surgery procedures (we may need them after reading so many papers).

Publisher Copyright:
© 2017 John Wiley & Sons Ltd.

Keywords

  • Clustering methods
  • Conservation
  • Delta K
  • Management
  • Optimal K
  • Population genetic structure

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics

Fingerprint

Dive into the research topics of 'The K = 2 conundrum'. Together they form a unique fingerprint.

Cite this