Shape analysis of symmetric structures: quantifying variation among individuals and asymmetry.
Details
Serval ID
serval:BIB_E83A5289725C
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Shape analysis of symmetric structures: quantifying variation among individuals and asymmetry.
Journal
Evolution; international journal of organic evolution
ISSN
0014-3820 (Print)
ISSN-L
0014-3820
Publication state
Published
Issued date
10/2002
Peer-reviewed
Oui
Volume
56
Number
10
Pages
1909-1920
Language
english
Notes
Publication types: Journal Article
Publication Status: ppublish
Publication Status: ppublish
Abstract
Morphometric studies often consider parts with internal left-right symmetry, for instance, the vertebrate skull. This type of symmetry is called object symmetry and is distinguished from matching symmetry, in which two separate structures exist as mirror images of each other, one on each body side. We explain a method for partitioning the total shape variation of landmark configurations with object symmetry into components of symmetric variation among individuals and asymmetry. This method is based on the Procrustes superimposition of the original and a reflected copy of each landmark configuration and is compatible with the two-factor ANOVA model customary in studies of fluctuating asymmetry. We show a fully multivariate framework for testing the effects in the two-factor model with MANOVA statistics, which also applies to shapes with matching symmetry. We apply the new methods in a small case study of pharyngeal jaws of the Neotropical cichlid fish Amphilophus citrinellus. The analysis revealed that the symmetric component of variation in the pharyngeal jaws is dominated by the contrast between two alternative trophic morphs in this species and that there is subtle but statistically significant directional asymmetry. Finally, we provide some general recommendations for morphometric studies of symmetric shapes.
Keywords
Analysis of Variance, Animals, Biometry/methods, Body Patterning, Cichlids/anatomy & histology, Cichlids/physiology, Humans, Mathematics, Models, Anatomic, Software
Pubmed
Web of science
Open Access
Yes
Create date
19/11/2007 10:52
Last modification date
12/05/2023 10:29