Open AccessDirectional asymmetry and the measurement of developmental instability
Author(s) -
Graham John H.,
Emlen John M.,
Freeman D. Carl,
Leamy Larry J.,
Kieser Jules A.
Publication year - 1998
Publication title -
biological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.906
H-Index - 112
eISSN - 1095-8312
pISSN - 0024-4066
DOI - 10.1111/j.1095-8312.1998.tb01530.x
Subject(s) - fluctuating asymmetry , instability , asymmetry , residual , trait , antisymmetric relation , mathematics , statistics , biology , physics , ecology , computer science , quantum mechanics , mechanics , mathematical physics , programming language , algorithm
Three widely used methods of estimating fluctuating asymmetry may yield serious overestimates if directional asymmetry is present. When two sides of a bilateral trait grow at different rates, then the asymmetry variance (Var[l‐r]) increases with size, even when developmental noise is nil. But the residual variance around a population's mean developmental trajectory is invariant with respect to size. Thus, it can be used as a measure of developmental instability. We introduce a measure of developmental instability, the residual variance (s 2 δ), obtainable from either a major axis regression, which is equivalent to a principal component analysis on l and r, or a general structural model. This residual variance can be estimated from directionally asymmetric or even antisymmetric traits. We present examples of developmental instability estimated from directionally asymmetric mandibles (house mouse) and leaves (soybean), and antisymmetric claws (fiddler crab).