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FLUCTUATING ASYMMETRY: AN EPIGENETIC MEASURE OF STRESS
Author(s) -
PARSONS P. A.
Publication year - 1990
Publication title -
biological reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.993
H-Index - 165
eISSN - 1469-185X
pISSN - 1464-7931
DOI - 10.1111/j.1469-185x.1990.tb01186.x
Subject(s) - biology , fluctuating asymmetry , epigenetics , evolutionary biology , natural selection , vertebrate , genetics , environmental stress , adaptation (eye) , zoology , ecology , domestication , range (aeronautics) , gene , selection (genetic algorithm) , neuroscience , artificial intelligence , computer science , materials science , composite material
Summary (1) Fluctuating asymmetry (FA) is a useful trait for monitoring stress in the laboratory and in natural environments. (2) Both genomic and environmental changes can increase FA which represents a deterioration in developmental homeostasis apparent in adult morphology. Genetic perturbations include intense directional selection and certain specific genes. Environmental perturbations include temperature extremes in particular, protein deprivation, audiogenic stress, and exposure to pollutants. (3) There is a negative association between FA and heterozygosity in a range of taxa especially fish, a result consistent with FA being a measure of fitness. (4) Scattered reports on non‐experimental populations are consistent with experiments under controlled laboratory conditions. FA tends to increase as habitats become ecologically marginal; this includes exposure to environmental toxicants. (5) In our own species, FA of an increasing range of traits has been related to both environmental and genomic stress. (6) Domestication increases FA of the strength of homologous long bones of vertebrate species due to a relaxation of natural selection. (7) FA levels are paralleled by the incidence of skeletal abnormalities in stressful environments. (8) Increased FA is a reflection of poorer developmental homeostasis at the molecular, chromosomal and epigenetic levels.