Quentin Martinez: Investigating Olfaction in Mammalian Evolution with Amira-Avizo Software

Amira-Avizo Software sheds light on mammalian evolution

Anatomy can often tell the story of an animal’s evolution. High-resolution visualization of anatomical structures requires high-quality imaging as well as robust 3D reconstruction software. By combining X-ray microtomography (microCT) with Thermo Scientific Amira-Avizo Software, Quentin Martinez, PhD, was able to produce novel insights into the evolution of amphibious mammals via olfaction.

Convergent evolution

Convergent evolution describes the development of physically and/or functionally identical traits in otherwise genetically unrelated organisms. The most widely known examples are likely found in mammalian evolution (i.e., bats, dolphins, platypuses, etc.) but it occurs regularly across all areas of life, appearing in plants, fungi, animals, and even prokaryotic organisms like bacteria. Function is regularly derived from environmental stressors, leading not just to specialization, but also to a decrease in the prominence of less-essential features.

Olfaction in mammalian evolution

Olfaction is a key component of mammalian evolution and is involved in food detection, mating, and predator avoidance. The vomeronasal organ and the olfactory turbinals are two major olfactory organs that are involved in the detection of pheromones and general odors. The olfactory bulb centralizes sensory information from these two olfactory organs.

While smell is seen as essential for many mammals, amphibious mammals are hypothesized to have reduced olfactory capacities compared to their terrestrial relatives. This is thought to be true across most amphibious mammals despite the fact that mammals independently colonized aquatic environments at least thirty times. There have been very few studies properly investigating the convergent evolution of reduced olfactory capacity in amphibious mammals.

Dr. Quentin Martinez on using Amira-Avizo Software in the investigation of mammalian evolution

Quentin Martinez, PhD, is a post-doctoral researcher at the State Museum of Natural History in Stuttgart (SMNS), Germany and completed his doctoral research at the Institut des Sciences de l´Évolution de Montpellier (ISEM). He specializes in the evolution of olfaction and thermoregulation in vertebrates, with a particular focus on the morpho-anatomical aspects of olfactory structures. Using Amira-Avizo Software and microCT, he is able to shed light on the evolution of olfactory organs in amphibious mammals.

“To understand the evolution of olfaction in amphibious mammals, I scan skulls or heads of museum specimens, sometimes collected more than a hundred years ago. This method allows me to access internal structures such as olfactory organs without damaging the museum specimens. I use Amira-Avizo Software to visualize, segment and quantify the olfactory organs.”

“We demonstrated that amphibious mammals have reduced olfactory turbinals in comparison to their close terrestrial relatives. Therefore, these amphibious species have potentially reduced olfactory capacities. We also demonstrated that this pattern is highly convergent.”

“Amira-Avizo Software has a very intuitive display control that allows me to change brightness and contrast to visualize hard and soft tissues. The brush tool with masking options allows me to accurately segment thin and complex structures such as turbinal bones. Finally, the generating surface has several smoothing and transparency options that give me the possibility to do great anatomical plates.”

“Personally what I like about this software is the friendly design that helps you quickly understand how the main tools work, similar to photo or digital editing software. For example, when I teach Amira-Avizo Software to my students they very quickly become fully autonomous on the software.”

Learn more about Amira-Avizo Software >>

Acknowledgements

The author acknowledges l‘Agence Nationale de la Recherche (Défi des autres savoirs, Grants DS10, ANR-17-CE02-0005 RHINOGRAD 2017, Pierre-Henri Fabre), Synthesis of Systematic Resources (SYNTHESYS, financed by European Community Research Infrastructure Action, Grants GB-TAF-5737, GB-TAF-6945, and GB-TAF-1316 to the National History Museum London – NHM UK), and the Alexander von Humboldt foundation that funded this research.

References

Martinez, Q., J. Clavel, J. A. Esselstyn, A. S. Achmadi, C. Grohé, N. Pirot, and P.-H. Fabre. (2020). Convergent evolution of olfactory and thermoregulatory capacities in small amphibious mammals. Proceedings of the National Academy of Sciences, 117(16), 8958-8965.

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This blog was written in collaboration between Séverine Baillet, PhD, a project manager at Thermo Fisher Scientific and Alex Ilitchev, PhD, a lead scientific editor at Thermo Fisher Scientific.