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The fate of balanced, phenotypic polymorphisms in fragmented metapopulations

journal contribution
posted on 2023-06-07, 21:00 authored by Paul G Craze
In large populations, genetically distinct phenotypic morphs can be maintained in equilibrium (at a 1 : 1 ratio in the simplest case) by frequency-dependent selection, as shown by Sewall Wright. The consequences of population fragmentation on this equilibrium are not widely appreciated. Here, I use a simple computational model to emphasize that severe fragmentation biases the morph ratio towards the homozygous recessive genotype through drift in very small populations favouring the more common recessive allele. This model generalizes those developed elsewhere for heterostylous plants and major histocompatibility complex alleles, emphasizes one particular outcome and avoids the restricting assumptions of more analytical models. There are important implications for both fundamental evolutionary biology and conservation genetics. I illustrate this with a range of examples but refer particularly to shell polymorphism in snails. These examples show how habitat fragmentation could have a direct and often unappreciated effect on species at the level of their population genetics.

History

Publication status

  • Published

Journal

Journal of Evolutionary Biology

ISSN

1420-9101

Publisher

Wiley-Blackwell

Issue

7

Volume

22

Page range

1556 - 1561

Department affiliated with

  • Biology and Environmental Science Publications

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2012-02-06

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