Abstract
Towards the origins of mineralization in vertebrates /nSkeleton mineralization (bones and teeth) was a crucial event in vertebrate diversification. However, although fossil records reveal that early mineralized vertebrates possessed enamel, dentin and bone, current genomic data do not allow finding the genes encoding proteins controlling mineralization of bone and teeth in all vertebrate lineages. /n /nEvolutionary story of mineralizing proteins in vertebrates /nGoing back in geological periods towards the origins of mineralization of bone and tooth tissues of early vertebrates and understanding how mineralization tools evolved in the various lineages (sharks, rays, bony ray fish, tetrapods) are the main objective of this study. In order to reach this objective the only transcriptome sequencing could bring us data that are lacking on mineralizing protein genes of the current non mammalian vertebrate lineages.Indeed, in contrast to more than 60 mammalian genomes sequenced or in course of, the total of sequenced genomes in all non mammalian lineages is less than 30. /n /nSearching for mineralizing protein genes using transcriptome sequencing /nWe have selected representative species for the main vertebrate lineages (one crocodile, lizard, salamander, lungfish, bichir, gar pike, several teleosts, shark and ray) and extracted RNA from jaws in order to sequence the transcriptome (i.e. all transcripts of genes that were expressed in the jaw at a given time) in which tooth and bone genes were present. These genes are looked for in the transcriptomes using in silico approaches and their structure and composition are analyzed through an evolutionary context in order to identify events that have occurred during long lasting geological periods.
France