FLUCTUATING ASYMMETRY IN MACACA-FASCICULARIS - A STUDY OF THE ETIOLOGY OF DEVELOPMENTAL NOISE

Fluctuating asymmetry was determined for six cranial measurements in a n age-diverse sample of 138 individuals of Macaca fascicularis. These data were used to choose among four hypotheses concerning the etiology of developmental noise. The hypotheses considered are (1) that develo pmental noise represents asymmetry in the causal history of a developi ng organism's interaction with the environment, (2) that it represents stochasticity in the mechanics of growth and induction, (3) that it r eflects variation in the initial conditions of a developmental process , and (4) that it represents the random accumulation of noise at a lev el below that of morphogenetic mechanism. These hypotheses were tested against predictions concerning the intraspecific patterning of fluctu ating asymmetry against age and size and the covariation of asymmetry values. Only the predictions of the fourth hypothesis were confirmed b y results of this study. These results provide evidence for the view t hat developmental noise, as reflected by fluctuating asymmetry, is an intrinsic property of developmental systems, and not merely produced b y the complexity of the organism's interaction with the environment.