Population fragmentation drives up genetic diversity in signals of individual identity

Calvin Dytham, Michael D.F. Thom*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Many species advertise their unique identity to conspecifics using dedicated individuality signals: one familiar example is human faces. But how unique in the global population do these signals need to be? While human faces are highly variable, each person interacts with many fewer individuals than are found in the total population. This raises the question of how evolutionary mechanisms drive up population-wide diversity when selection occurs at such a local level. We use an individual-based model in which individuals broadcast their identity and quality in separate, genetically-coded signals. Mimicking, for example, scent marking mammal species, females in the model assess males using the quality signal, then attempt to relocate the highest quality male using his identity signal. We ask how population fragmentation affects genetic diversity in the individual identity-signalling region under sexual selection, predicting one of two opposing outcomes: 1) divided populations evolve fewer signal variants globally, since repetition of signals is not costly when individuals interact only with local conspecifics, or 2) stochasticity in mutation and selection cause divergence among subpopulations, increasing the global number of signal variants. We show that local selection drives up global genetic diversity substantially in fragmented populations, even with extremely low rates of dispersal. Because new signal variants arise by mutation and then sweep through their subpopulation, a fragmented population has more global signal variation. This result furthers our understanding of how high levels of diversity in individuality signals are maintained.

Original languageEnglish
Pages (from-to)526-532
JournalOikos
Volume129
Issue number4
Early online date13 Dec 2019
DOIs
Publication statusPublished - Apr 2020

Bibliographical note

© 2019 Nordic Society Oikos. Published by John Wiley & Sons Ltd. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

Keywords

  • agent-based model
  • dispersal
  • genetic diversity
  • individual recognition
  • individual-based model
  • mate choice
  • population fragmentation
  • sexual selection

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