Related Experiment Video
Updated: Jun 1, 2026

Why Quantification Matters: Characterization of Phenotypes at the Drosophila Larval Neuromuscular Junction
Published on: May 12, 2016
Multiple quantitative trait loci influence intra-specific variation in genital morphology between phylogenetically
M A Schäfer1, J Routtu, J Vieira
1Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland. m_schaefer_de@yahoo.de
Abstract:
The evolution of animal genitalia has gained renewed interest because of their potential roles during sexual selection and early stages of species formation. Although central to understanding the evolutionary process, knowledge of the genetic basis of natural variation in genital morphology is limited to a very few species. Using an outbred cross between phylogenetically distinct lines of Drosophila montana, we characterized quantitative trait loci (QTLs) affecting the size and shape of the distiphallus, a prominent part of the male intromittent organ. Our microsatellite-based linkage analysis shows that intra-specific variation in the distiphallus involves several QTLs of largely additive effect and that a highly significant QTL co-localizes with the same inversion where we have earlier localized a large QTL for a sexually selected courtship song trait. The latter indicates that inversions can play an important role in shaping the evolution of rapidly evolving traits with a potential influence on speciation.
Related Concept Videos
Background and Environment Affect Phenotype
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
The Ratio of X Chromosome to Autosomes
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
Dihybrid Crosses
Polygenic Traits
Position-effect Variegation
Evolutionary Relationships through Genome Comparisons

