Recently published in the prestigious magazine Molecular Biology and Evolutionthe study is the result of the work of the Dr Sylvain MarcelliniFBC academic in collaboration with researchers from the University of Montpellier in France.
“Our laboratory investigates the genomic and genetic bases that underlie the evolutionary origin of the skeleton, which consists of an assembly of cartilage, bones and teeth. This particular work investigates the evolution of the hypermineralized enamel that covers our teeth.how it appeared in the group of vertebrates and how it has been changing in different lineages”, explained Sylvain Marcellini, academic from the FCB Department of Cell Biology and researcher of the Group for the study of Processes in Developmental Biology (GDeP).
The work was published in the journal Molecular Biology and Evolution, whose impact factor is greater than 16, placing it in the first quintile of the best journals in this discipline.
This finding is the fruit of a dynamic and productive collaboration with Dr. Mélanie Debiais-Thibaud, from the University of Montpellier in France..
The most striking point of the research is that Parallel evolution of genes was demonstrated. This means that a case was found where the same gene appeared twice in evolution, in completely independent ways.
“These are very rare events because the probability of exactly the same mutational steps happening twice or more is low, but not impossible,” argued the researcher.
“To date, the prevailing dogma was that biomineralization genes called SCPP exist only in bony vertebrates, a large group that includes humans. We identified a SCPP gene in the genome of sharks (a group of cartilaginous vertebrates. In addition, we show that the same mutational processes occurred in parallel in bony and cartilaginous vertebratessince in both cases SCPP was produced by duplication of the same precursor gene called SPARC-L”, explained the researcher
“This case of parallelism encompasses genomic, gene, expression, and protein structure aspects, the similarities are so many that it is legitimate to call the new shark gene SCPP,” said Dr. Marcellini.
Finally, the work resolves an old controversy about the evolutionary relationship of the hypermineralized layer that covers the teeth of cartilaginous and bony vertebrates.
Traditionally, this layer has been called “enamel” in sharks and “true enamel” in mammals and it was thought that they have no evolutionary relationship. In the post-genomic era, this old idea was reinforced by the putative absence of SCPP genes in cartilaginous vertebrates.
According to Dr. Marcellini, the work “confirms the homology in the enamel layer that covers the teeth of all vertebrates, which implies that this layer appeared only once in evolution and was inherited in all lineages. The main argument we make is that enamel and enamel share a common genetic and cellular basis, as shown by the expression of SPARC-L in shark ameloblasts.”
“We are very proud of this achievement, because we are contributing to human culture and in itself that is a great reason for the existence of science. Understand the world that surrounds us, where we come from, what we are and where we are going”, concluded the professor.
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