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Proc Biol Sci. 2009 Jun 22;276(1665):2271-8. doi: 10.1098/rspb.2009.0183. Epub 2009 Mar 18.

What can genetic variation tell us about the evolution of senescence?

Author information

1
Department of Genetics, University of Georgia, Athens, GA 30602, USA. jmoorad@uga.edu

Abstract

Quantitative genetic approaches have been developed that allow researchers to determine which of two mechanisms, mutation accumulation (MA) or antagonistic pleiotropy (AP), best explain observed variation in patterns of senescence using classical quantitative genetic techniques. These include the creation of mutation accumulation lines, artificial selection experiments and the partitioning of genetic variances across age classes. This last strategy has received the lion's share of empirical attention. Models predict that inbreeding depression (ID), dominance variance and the variance among inbred line means will all increase with age under MA but not under those forms of AP that generate marginal overdominance. Here, we show that these measures are not, in fact, diagnostic of MA versus AP. In particular, the assumptions about the value of genetic parameters in existing AP models may be rather narrow, and often violated in reality. We argue that whenever ageing-related AP loci contribute to segregating genetic variation, polymorphism at these loci will be enhanced by genetic effects that will also cause ID and dominance variance to increase with age, effects also expected under the MA model of senescence. We suggest that the tests that seek to identify the relative contributions of AP and MA to the evolution of ageing by partitioning genetic variance components are likely to be too conservative to be of general value.

PMID:
19324735
PMCID:
PMC2677612
DOI:
10.1098/rspb.2009.0183
[Indexed for MEDLINE]
Free PMC Article

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