Developmental studies using the temporal bones of a primate model animal

Abstract

In recent years, expectations of gene therapy for congenital hearing loss or inner ear regeneration have increased with the accumulation of molecular biological findings; however, obtaining scientific knowledge on human inner ear development has become progressively difficult due to ethical issues. Therefore, rodent models have been frequently used in the studies of inner ear regeneration and development, and many results have been achieved. However, the evolution of the cochlea from rodents to primates and humans has not been studied extensively.

The acquisition of the cochlea as a hearing organ is relatively new in evolutionary history. As a cochlea is present only in mammals, the structure of the cochlea has been known to show morphological differences among them. Scientific interest in the auditory organs of vertebrates, which have dynamically changed their morphology during evolution, is one of the oldest scientific challenges; this knowledge of “evolution” sometimes provides us with important insights when studying “development.”

In this study, we focus on the common marmoset, which is used as a primate model animal in our department. In addition, we report our recent findings on the varying effects of evolution and species in terms of inner ear development by comparing inner ear development in humans and rodent models based on evolutionary knowledge.