Maternal control of phenotypic evolution – CAVEMOM
CAVEMOM is a 535.620€ basic research collaborative project involving 2 French partners and a Swiss partner over 4 years.
Evolutionary developmental biology seeks to unravel the ontogenetic variations that lead to morphological variations between species. But how early in development can these embryonic variations arise?
Animal development is initially directed by maternal gene products deposited in the egg during oogenesis. These maternal products entirely control the first steps of development before the maternal-to-zygotic transition, including the formation of the embryonic axes and dorsal organizer. Here, we will investigate the contribution of these maternal factors to the phenotypic evolution of a blind cavefish.
We will take advantage of the two morphs of the species Astyanax mexicanus, which have diverged recently and are inter-fertile, to break new ground in the field by looking at “evolution in action”. We will explore the maternal control of the complete loss of eyes and sensory compensations that accompanied evolution and adaptation of cavefish in the dark. We propose a multiscale approach that utilizes systems developmental biology tools to characterize the evolution of maternal contribution in cavefish (aim1), to understand its morphogenetic consequences (aim2) and to decipher its origins (aim3).
1. We will characterize the maternal genes involved in variations of very precocious embryogenesis, including the formation of the organizer, in cavefish and their river-dwelling conspecifics, and we will identify the causative changes in the cavefish regulatory genome.
2. We will decipher how such variations in maternal control of embryogenesis translate into variations in gastrulation and neurulation morphogenetic processes. We will focus on specific tissues (organizer, prechordal plate, anterior neural plate) and determine disparities in their cellular transcriptomic signatures and cellular behaviors that directly affect cavefish traits.
3. We will establish a comparative molecular portrait of oogenesis in cavefish and their river-dwelling conspecifics to understand the origins of maternal genes expression and regulation in the mother’s gonads.
In other words, we will ask whether phenotypic evolution can originate from variations in very precocious developmental events, starting even before fertilization, during the assembly of the egg in the mother's gonad. CAVEMOM is the first study on the role of extremely early, maternally controlled events in morphological evolution.
Our consortium is composed of world-leading groups in the fields of evolutionary developmental biology, developmental neurobiology and fish reproductive biology. We master the methodologies used in the project, and we closely collaborate with and are supported by top-level platforms for sequencing, bioinformatics, genome edition, and imaging that will be necessary during the course of CAVEMOM. The proposed tasks and hypotheses rely on original and strong preliminary and published results. Project outcomes will be translated into original outreach and teaching actions.
Madame Sylvie RETAUX (Institut des Neurosciences Paris Saclay)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
Neuro-PSI Institut des Neurosciences Paris Saclay
LPGP Laboratoire de Physiologie et Génomique des Poissons
Help of the ANR 478,619 euros
Beginning and duration of the scientific project: December 2021 - 48 Months