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FITNESS AND ADAPTATION IN A NOVEL ENVIRONMENT: EFFECT OF INBREEDING, PRIOR ENVIRONMENT, AND LINEAGE
Author(s) -
Reed David H.,
Lowe Edwin H.,
Briscoe David A.,
Frankham Richard
Publication year - 2003
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.0014-3820.2003.tb00589.x
Subject(s) - biology , inbreeding , adaptation (eye) , population , inbred strain , selection (genetic algorithm) , evolutionary biology , adaptability , replicate , genetic fitness , lineage (genetic) , genetic variation , genetics , effective population size , inbreeding depression , genetic load , ecology , demography , statistics , biological evolution , gene , mathematics , neuroscience , artificial intelligence , sociology , computer science
. The ability of populations to undergo adaptive evolution depends on the presence of genetic variation for ecologically important traits. The maintenance of genetic variation may be influenced by many variables, particularly long‐term effective population size and the strength and form of selection. The roles of these factors are controversial and there is very little information on their impacts for quantitative characters. The aims of this study were to determine the impacts of population size and variable versus constant prior environmental conditions on fitness and the magnitude of response to selection. Outbred and inbred populations of Drosophila melanogaster were maintained under benign, constant stressful, and variably stressful conditions for seven generations, and then forced to adapt to a novel stress for seven generations. Fitness and adaptability were assayed in each replicate population. Our findings are that: (1) populations inbred in a variable environment were more adaptable than those inbred in a constant environment; (2) populations adapted to a prior stressful environment had greater fitness when reared in a novel stress than those less adapted to stress; (3) inbred populations had lower fitness and were less adaptable than the outbred population they were derived from; and (4) strong lineage effects were detectable across environments in the inbred populations.