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STABILIZING SELECTION DETECTED FOR BRISTLE NUMBER IN DROSOPHILA MELANOGASTER
Author(s) -
GarcíaDorado Aurora,
González Jorge A.
Publication year - 1996
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.1996.tb03929.x
Subject(s) - bristle , biology , trait , selection (genetic algorithm) , pleiotropy , drosophila melanogaster , stabilizing selection , evolutionary biology , directional selection , disruptive selection , population , genetics , natural selection , phenotype , genetic variation , gene , demography , brush , artificial intelligence , sociology , computer science , electrical engineering , programming language , engineering
Stabilizing selection, which favors intermediate phenotypes, is frequently invoked as the selective force maintaining a population's status quo. Two main alternative reasons for stabilizing selection on a quantitative trait are possible: (1) intermediate trait values can be favored through the causal effect of the trait on fitness (direct stabilizing selection); or (2) through a pleiotropic, deleterious side effect on fitness of mutants affecting the trait (apparent stabilizing selection). Up to now, these alternatives have never been experimentally disentangled. Here we measure fitness as a function of the number of abdominal bristles within four Drosophila melanogaster lines, one with high, one with low, and two with intermediate average bristle number. The four were inbred nonsegregating lines, so that apparent selection due to pleiotropy is not possible. Individual fitness significantly increased (decreased) with bristles number in the low (high) line. No significant fitness‐trait association was detected within each intermediate line. These results reveal substantial direct stabilizing selection on the trait.