Genetics. Published Articles Ahead of Print: August 20, 2008, Copyright © 2008
doi:10.1534/genetics.108.088906


A more recent version of this article appeared on September 1, 2008.

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Quantitative trait loci affecting phenotypic plasticity and the allometric relationship of ovariole number and thorax length in Drosophila melanogaster

Alan O. Bergland 1*, Anne Genissel 2, Sergey V. Nuzhdin 3 and Marc Tatar 1

1 Brown University
2 University of California, Davis
3 University of Southern California

* To whom correspondence should be addressed. E-mail: alan_bergland{at}brown.edu.

Submitted on March 5, 2008
Revised on May 9, 2008
Accepted on 21 June 2008


Abstract

Environmental factors during juvenile growth such as temperature and nutrition have major effects on adult morphology and life-history traits. In Drosophila melanogaster, ovary size, measured as ovariole number, and body size, measured as thorax length, are developmentally plastic traits with respect to larval nutrition. Herein we investigated the genetic basis for plasticity of ovariole number and body size, as well the genetic basis for their allometric relationship using recombinant inbred lines (RILs) derived from a natural population in Winters, CA. We reared 196 RILs under four yeast concentrations and measured ovariole number and body size. The genetic correlation between ovariole number and thorax length was positive, but the strength of this correlation decreased with increasing yeast concentration. Genetic variation and genotype-by-environment interactions (GxE) were observed for both traits. We identified QTL, epistatic, QTL- and epistatic-by-environment interactions for both traits and their scaling relationships. The results are discussed in the context of multivariate trait evolution.

Key Words: Allometry, Ovariole number, Phenotypic plasticity, Quantitative Trait Loci (QTL), Thorax length