Population on the verge of a mutational meltdown? Fitness costs of genetic load for an amphibian in the wild

Rowe, Graham and Beebee, Trevor J C (2003) Population on the verge of a mutational meltdown? Fitness costs of genetic load for an amphibian in the wild. Evolution, 57 (1). pp. 177-181. ISSN 0014-3820

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Abstract

The fitness costs of high genetic load in wild populations have rarely been assessed under natural conditions. Such costs are expected to be greatest in small, bottlenecked populations, including those occurring near range edges. Britain is at the northwesterly range limit of the natterjack toad Bufo calamita. We compared fitness attributes in two populations of this amphibian with very different recent histories. Key larval fitness attributes in B. calamita, notably growth rate and metamorph production, were substantially higher in the large outbreeding population (Ainsdale) than in the small and isolated one (Saltfleetby). These differences were manifest under seminatural conditions, when larvae were reared in mesh cages within breeding ponds at the site of the small population, and were exacerbated by high stress treatments. The results indicate that genetic load effects can be sufficiently severe enough to predispose extinction over relatively short time frames, as predicted by extinction vortex models.

Item Type: Article
Additional Information: The effects of genetic load (inbreeding etc) on isolated wild populations are of increasing concern. Here we demonstrated severe adverse effects on fitness of a small natterjack toad population, essentially the first time this has been done.
Schools and Departments: School of Life Sciences > Evolution, Behaviour and Environment
Depositing User: Trevor Beebee
Date Deposited: 06 Feb 2012 21:14
Last Modified: 22 Mar 2012 15:01
URI: http://sro.sussex.ac.uk/id/eprint/30407
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