Drosophila wing modularity revisited through a quantitative genetic approach.
To predict the response of complex morphological structures to selection it is necessary to know how the covariation among its different parts is organized. Two key features of covariation are modularity and integration. The Drosophila wing is currently considered a fully integrated structure. Here, we study the patterns of integration of the Drosophila wing and test the hypothesis of the wing being divided into two modules along the proximo-distal axis, as suggested by developmental, biomechanical, and evolutionary evidence. To achieve these goals we perform a multilevel analysis of covariation combining the techniques of geometric morphometrics and quantitative genetics. Our results indicate that the Drosophila wing is indeed organized into two main modules, the wing base and the wing blade. The patterns of integration and modularity were highly concordant at the phenotypic, genetic, environmental, and developmental levels. Besides, we found that modularity at the developmental level was considerably higher than modularity at other levels, suggesting that in the Drosophila wing direct developmental interactions are major contributors to total phenotypic shape variation. We propose that the precise time at which covariance-generating developmental processes occur and/or the magnitude of variation that they produce favor proximo-distal, rather than anterior-posterior, modularity in the Drosophila wing.
Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Avinguda de l'Eix Central, Edifici C, E-08193 Bellaterra (Cerdanyola del Vallès), Spain. francesc.munozm@uab.cat.
Francesc
F
Muñoz-Muñoz
Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA - CONICET) DEGE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Int. Guiraldes 2160, Buenos Aires, Argentina.
Valeria Paula
VP
Carreira
CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003, Barcelona, Spain.|Universitat Pompeu Fabra (UPF), Barcelona, Spain.
Neus
N
Martínez-Abadías
Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA - CONICET) DEGE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Int. Guiraldes 2160, Buenos Aires, Argentina.
Victoria
V
Ortiz
Instituto Patagónico de Ciencias Sociales y Humanas, Centro Nacional Patagónico, Consejo Nacional de Investigaciones Científicas y Técnicas, Puerto Madryn, Argentina.
Rolando
R
González-José
Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA - CONICET) DEGE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Int. Guiraldes 2160, Buenos Aires, Argentina.
Ignacio M
IM
Soto
D000818:Animals; D005075:Biological Evolution; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development*; D005260:Female; D008297:Male; D009024:Morphogenesis; D014921:Wings, Animal / Q000254:growth & development
Drosophila wing; modularity; multilevel approach; proximo-distal axis