A Study of Fluctuating Asymmetry

Valen, Leigh Van

doi:10.2307/2406192

Cited by 1,044 publications

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“…In principle, there can be genetic variation in both components, but it may not be possible to separate them. An indicator of robustness and of fitness, widely used in evolutionary studies, is FA (Van Valen, 1962), which is a measure of individual asymmetry in bilateral traits that are symmetric at the population level, for example, features of a fly's wing or a human face and is measured as the variance in E s . In this review, we shall concentrate primarily on the variation among individuals ; reviews on FA have been published elsewhere (e.g.…”

Section: Introductionmentioning

confidence: 99%

Genetic analysis of environmental variation

2010

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SummaryEnvironmental variation (V E ) in a quantitative trait -variation in phenotype that cannot be explained by genetic variation or identifiable genetic differences -can be regarded as being under some degree of genetic control. Such variation may be either between repeated expressions of the same trait within individuals (e.g. for bilateral traits), in the phenotype of different individuals, where variation within families may differ, or in both components. We consider alternative models for defining the distribution of phenotypes to include a component due to heterogeneity of V E . We review evidence for the presence of genetic variation in V E and estimates of its magnitude. Typically the heritability of V E is under 10 %, but its genetic coefficient of variation is typically 20 % or more. We consider experimental designs appropriate for estimating genetic variance in V E and review alternative methods of estimation. We consider the effects of stabilizing and directional selection on V E and review both the forces that might be maintaining levels of V E and heritability found in populations. We also evaluate the opportunities for reducing V E in breeding programmes. Although empirical and theoretical studies have increased our understanding of genetic control of environmental variance, many issues remain unresolved.

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Section: Introductionmentioning

confidence: 99%

Genetic analysis of environmental variation

2010

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“…Loin de proposer l'abandon de l'asymétrie fluctuante comme sujet d'étude, l'auteur présente certaines pistes de recherche parmi les plus prometteuses. < DÉBAT FORUM donc en premier lieu été étudiée dans l'objectif de comprendre les processus développemen-taux assurant la stabilité du phénotype et la précision de la morphogenèse [3,10].…”

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“…C'est le cas des pinces chez certaines espèces de crabes violonistes (Figure 2). Cette typologie des asymétries est clairement établie depuis longtemps [3], et les méthodes d'étude statistiques et expérimentales ont été détail-lées notamment par Palmer et Strobeck [5,6].…”

Section: Prologueunclassified

“…Si l'asymétrie directionnelle et l'antisymétrie sont supposées être adaptatives, l'asymétrie fluctuante est généralement considérée comme une nuisance : elle résulterait du bruit développemental et de l'incapacité du développement à absorber ce bruit [3,7]. Cette idée repose sur un raisonnement simple : les deux côtés d'un organe globalement symétrique étant contrôlés par les mêmes gènes et soumis aux mêmes influences environnementales, la variation résiduelle (l'asymétrie fluctuante) est nécessairement de nature stochastique.…”

Section: Des Raisons D'étudier L'asymétrie Fluctuante ?unclassified

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Symmetry is beauty – or is it?

Debat

2016

Med Sci (Paris)

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“…We all have had similar experiences in individuals with small and contralateral absent thumb or, small/triphalangeal thumb, small auricle/microtia-anotia, small/absent upper lateral incisors/broad/bifid upper lateral incisors, brother with broad/sister with cleft xiphisternum, etc. Thus, it seems appropriate to propose a hypothesis: Bilaterally symmetrical structures of the human body (which are conjoint MZ twins) are subject to fluctuating asymmetry [FA, Ludwig, 1932van Valen, 1962;Livshits et al, 1998;Opitz and Utkus, 2001]: random differences between the two sides of quantitative traits. These increase in parallel to the decreased buffering ability of an organism, thus, are a measure of developmental (in)stability: The greater the FA the less the developmental stability.…”

Section: Minor Anomalies and Mild Malformationsmentioning

confidence: 99%

Historical perspective on developmental concepts and terminology

Opitz

Neri

2013

American J of Med Genetics Pt A

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In their ontogeny and phylogeny all living beings are historical entities. The revolution in biology of the 18th and 19th centuries that did away with the scala naturae according to which we humans, the acme of creation, “made a little lower than the angels,” also led to the gradual realization that a humble one‐celled protist (“protoctist”), such as Entamoeba histolytica of ill repute [Margulis and Chapman, ] has the same 4‐billion‐year phylogeny as that of Homo sapiens, vivid testimony to common ancestry and the relatedness of all living beings on earth. The group of medical geneticists who assembled at the NIH, Bethesda, MD this January to address terms pertaining to human ontogeny, did so in the long tradition of Sydenham, Linnaeus, Meckel, Geoffroy St‐Hilaire père et fils, Wilhelm His and so many others before who had over the previous two centuries wrestled as earnestly as they could with concepts of “classification” and nomenclature of developmental anomalies. The prior massive need for classification per se in medical morphology has diminished over the years in favor of ever more sophisticated understanding of pathogenesis and cause through experimental biology and genetics; however, in the winter of 2013 it was still found prudent to respect terminological precedent on general terms while recognizing recent advances in developmental pathology requiring clarification and definition of special terms. Efforts along similar lines instigated by the German Society of Anatomists at their first meeting in Leipzig in 1887 culminated, after intense years of work by hundreds of experts and consultants under the goad of Wilhelm His, in the Basel Nomina Anatomica [BNA, His (1895)]. His, himself, stated prefatorily that the BNA had no legislative weight, only an evanescent consensus of many to be amended in the future as needed and indicated. Without hubris, no one before or after will do the same. The more substantial the consensus the more permanent the structure. After some 120 years the BNA is alive and flourishing. Now retitled Terminologia Anatomica, it has been amended and added to many times, is still in Latin but now with synonyms in English, the new lingua franca of science, for every anatomical, histological and embryological term. May our successors be equally effective. © 2013 Wiley Periodicals, Inc.

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A Study of Fluctuating Asymmetry

Cited by 1,044 publications

References 0 publications

Genetic analysis of environmental variation

Genetic analysis of environmental variation

Symmetry is beauty – or is it?

Historical perspective on developmental concepts and terminology

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