MORPHONECK

The neck, specific to tetrapods, emerged congruent with limbs during the vertebrate water-to-land transition. This morphological innovation resulted from the adaptation of the musculoskeletal system and required profound developmental rearrangements. In vertebrates, the musculoskeletal systems of the head and trunk have different evolutionary and embryonic origins and their development depends on distinct molecular mechanisms. The neck region constitutes a transition zone of mixed embryonic origin at the head-trunk interface and the morphogenetic actors regulating its formation remain elusive. The present project aims to determinate the developmental processes at the origin of the neck musculoskeletal system in tetrapods. By genetic conditional inactivation strategies in the mouse, we will investigate cellular and molecular actors of mammalian neck musculoskeletal assembly. Through high-throughput transcriptome profiling in the mouse embryo and advanced bioinformatics analyses, we will explore the transcriptomic signature and identify molecular determinants of mammalian neck morphogenesis. We will then compare the spatiotemporal expression of molecular actors of neck development in key conventional and unconventional organisms representative of major jawed vertebrate taxa. The study will determine conservation and divergence in genetic programs taking place at the head-trunk interface in fish, amphibian, mammalian, lizard and bird organisms. The complementary research axes will permit to elucidate the developmental determinants and evolutionary origins of the tetrapod neck. Our data will also bring new insights for the understanding of some human congenital disorders in which the neck musculoskeletal system is specifically affected.