Our goal is to understand how and why specific phenotypes arise during evolution. We use all the available approaches (genomics, developmental biology, biochemistry, behavioral assays, genetics, etc.) to tackle the problem.
Evolution of a new stable phenotype
How robust phenotypes evolve despite developmental noise remains unclear. Does evolution of a new phenotype goes through an intermediate unstable state that is then stabilized due to fixation of additional mutations? Or does it evolve directly as a new phenotype that is stable across various external conditions? We are examining the evolution of a new genital sensory organ pattern in Drosophila santomea and aim to better characterize the molecular mechanisms that stabilize this recently evolved phenotype. Our goal is three-fold: (1) characterize and compare the development of these structures in D. santomea and its closely-related species, (2) identify the underlying genes and mutations that act collectively to produce a robust phenotype in pure species, and (3) unveil the selective forces at play on this evolved phenotype.
Living on senita cactus
Drosophila pachea is one of the rare insect species that is unable to metabolise cholesterol. It lives exclusively on one host plant, the senita cactus, and it requires 7-dehydrogenated sterols produced by this cactus to survive. We identified several coding mutations in an enzyme gene that have made D. pachea dependent on its host cactus. Our work suggests that these mutations are beneficial for D. pachea and have been subject to positive selection.
Drosophila pachea has also evolved a resistance towards the toxic compounds of its host cactus. We would like to investigate the genetic basis of this resistance. We also plan to study how a moth species adapted to the senita cactus.
Evolution of left-right size asymmetry
How left-right asymmetries in organ size develop remains a mystery. Drosophila pachea has evolved a unique left-right asymmetry in genitalia lobes. No left-right size asymmetry has been described in D. melanogaster. We are trying to uncover the mechanisms that triger asymmetric lobe development and the role of these asymmetric lobes during copulation. We use a stock of Drosophila pachea containing spontaneous symmetric mutant males and we perform micro-scale laser removal of lobe bristles and micro-scale surgery of lobes. We are also examining left-right asymmetries in behavior and morphology in species closely related to D. pachea, in order to understand how left-right asymmetry in lobe size evolved in D. pachea.
Evolution of genital organ shape
We wish to understand how diverse biological forms develop and evolve. To try to understand how genes and cellular mechanisms modulate organ shape in a subtle and precise way, we are examining the precise changes in genital organ shape that have appeared during evolution in Drosophila melanogaster and its closely related species. In particular, we would like to identify genes and mutations responsible for specific changes in lobe shape and in ventral branches shape.
contains a list of all the genes and mutations that have been found to be responsible for phenotypic differences (morphological, physiological and behavioral traits) between populations or strains for pluricellular organisms. A preliminary list is deposited in Dryad and the new website under construction is available here.
provides a compilation of the phenotypes that have been reported to differ between at least two species of the D. melanogaster subgroup. More than 150 morphological, physiological and behavioral differences have been described between 1919 and 2006.
associated paper: Orgogozo V, Stern DL, How different are recently diverged species? More than 150 phenotypic differences have been reported for the D. melanogaster species subgroup. Fly 2009 Mar-Apr;3(2):117.
description of the embryonic and larval peripheral nervous system of D. melanogaster.
made with Wesley Grueber.
associated paper: Orgogozo V, Grueber WB, FlyPNS, a database of the Drosophila embryonic and larval peripheral nervous system. BMC Dev Biol. 2005 Feb 17; 5(1):4.
Link to our list of protocols