Étudiant-chercheur étoile May 2017

Yacine Kherdlemil

PhD student in Molecular Biology
Institut de recherches cliniques de Montréal

Award-winning publication: Evolution of Hoxa11 regulation in vertebrates is linked to the pentadactyl state

Published in: Nature


Most living tetrapods (animal species with two pairs of limbs) are pentadactyl: they have five digits on each hand. In evolution, this characteristic is a recent specificity. The earliest species with digits had between six and eight on each hand. Yacine Kherdjemil and his team showed that it was the repression of the Hoxa11 gene by the Hoxa13 gene in limb development that led to the pentadactyl state. The researchers demonstrated that pentadactyl limbs are the result of the acquisition of a gene switch that regulates the expression of the Hoxa11 gene. The discovery illustrates the ways in which mutations in DNA sequences throughout evolution initiated morphological innovations and species diversification. From the clinical perspective, the findings support the notion that the malformations observed in foetuses may be caused by mutations in the DNA elements that increase or reduce gene expression and that these mutations may have a more significant impact than a mutation in the gene itself.