I am a biologist, and my long-term research vision is to incorporate a broad scope of disciplines to understand how biodiversity evolves and interacts with its environment. I have a particular interest in chemosensation, chemical evolution, and extreme adaptations.
Bat nasal goblet cells as immuno-hotspots for infection of SARs-cov-2
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Have you been wondering why bats are able to be infected by coronaviruses but seem to not manifest any symptoms? Well, I'm happy to report that, after thinking being expert in bat noses would never really mean anything to this planet, it turns out we are on the case! After months of isolating and feeling helpless in this pandemic, I am excited to announce that today marks the kick-off to our recently funded NSF-RAPID project "Bat nasal goblet cells as immuno-hotspots for infection of coronavirus". We are working on imaging specialized cells in bat noses that may be entry points for the virus, and trying to characterize how they differ from those in human noses. We will be looking specifically at immune-response proteins of these cells once we figure out potential candidates that may be responsible for differences. In short, the virus enters into the nose cells in both bats and humans, and for some reason doesn't elicit the nasty effects in bats as seen in humans. We are going to find out why. It is exciting to finally be working towards understanding this frustrating but fascinating virus. Here is a µCT-scan of a bat head, and you can notice the intricate structures in the nose we will be looking at in more detail.
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The role of diet in microbiome diversity
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Phyllostomid bats have diverged from an ancestral insectivorous diet and evolved the most diverse sets to feeding-strategies observed in vertebrates. While much is known on the morphological adaptations for the consumption of fruits and nectar, the role that the intestinal microbiome plays in digesting a plant-based diet is not well understood. We are using mobile DNA sequencing technology to obtain real-time data to sequence the microbiomes of bats with divergent diets.
My approach is to bring the labwork to the field. This "backpack" laboratory minimizes invasive sampling, decreases costs to make projects tractable for all, and builds capacity through simultaneously training colleagues in the field and lab. Using portable, low-cost technologies such as MinION, we are able to collect and data in real time, while exposing these methods to scientists all around the world. Our pilot project in the cloud forests of Colombia brought lots of promising preliminary results! |
Chemosensory receptor diversity in Sauropsids
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Squamates are well known for their tongue-flicking behavior responsible for detecting environmental chemical cues relevant to feeding and reproduction. However, little is known about the molecular basis of this chemical behavior or the diversity of receptors responsible for processing these chemical signals. Furthermore, chemosensation is a poorly studied sense in birds as well. I am characterizing the chemosensory diversity of birds and reptiles, and modeling the evolutionary history of gene family expansions
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developmental basis of chemosensory diversity
BigBoi. HH35 chick embryo immunostained for Pax3 (aqua) and cell nuclei (DAPI-orange). Pax3 marks a protein critical to neural crest development and spinal cord formation. Taken in collaboration with Andrea Attardi at the 2018 MBL Embryology course.
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As an NSF Postdoctoral Fellow at Yale University, I now incorporate developmental mechanisms into my research using new microscopy techniques and µCT-scans. I am exploring the origins of sensory brain regions across tetrapods, with implications of understanding sensory brain evolution from both a diversity of extant organisms to fossil taxa. I am extending pioneering methods often only applied to model organisms to embryo specimens to represent a broad diversity of species with different niches. Specifically, I am inferring the evolutionary origins of sensory cortex layers. I am combining this morphological data with the molecular evolution of sensory gene sequences. With this data, I am asking questions such as, do more visually-oriented animals devote more developmental resources to visual cortex layers versus olfactory regions? Or, can we infer ancestral conditions of sensory brain regions and extrapolate our understanding of extinct taxa, such as dinosaurs?
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Environmental influence on odor plumes and its effects on organismal detection
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Chemical signals and cues must stand out against the chemical background, and the recipient must detect the cue in time before the signal is diffused. The chemical environment is a dynamic and complex system influenced by various abiotic and biotic factors, but these factors have rarely been quantified. The qualification and quantification of light and sound are highly standardized through measurements of well-known physical properties (i.e., waves, wavelengths, and amplitudes), there is presently no unbiased way of capturing the entire breadth of chemicals from the environment, presenting a significant challenge for biogeochemistry. As part of my research program, I aim to establish both short- and long-term sampling strategies of the biogenic volatile organic compounds in different habitats (e.g. rainforest v. desert) and determine where these compounds are sourced from. For example, were these chemicals emitted directly from the plant or animal? or were they oxidized by the environment post-emission?
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Multiple scales of chemosensory interactions in an environment (Yohe & Brand, 2018). Characterizing the abiotic factors of the chemical background is of keen interest to me, which have implications to the signal detection and perception in animals and plants.
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Molecular evolution of olfactory receptors in Leaf-Nosed Bats
New World Leaf-nosed bats (Phyllostomidae) occupy an enormous range of dietary niches and natural selection has shaped an array of morphological and sensory adaptations to exploit these dietary niches. However, the molecular mechanisms that allowed populations to depart from their ancestral insectivorous diet and detect novel resources, such as nectar or fruit, are unknown. Phyllostomids need to find these resources while flying in the dark, and behavioral evidence has shown the sense of smell is a critical supplement to echolocation for detecting food in a cluttered environment. Combining transcriptomes and targeted sequence capture, I have sequenced the olfactory receptor profiles in dozens of phyllostomids with divergent diets. While I predicted a large duplication event in plant-visiting bats, I have identified many duplication events unique to particular bat subfamilies with unique diets.
MACROEVOLUTION AND ADAPTIVE RADIATION OF BABBLERS
Babblers (Timaliidae), are a species-rich group of passerines distributed throughout the Old World characterized by distinct phenotypic differences and highly diverse morphological features, including highly variable body size, bill structure, and plumage patterns. The evolutionary relationships among babblers have puzzled biologists for decades and the family is under constant revision. Although widely distributed, closely related species often coexist, suggesting niche partitioning among close relatives. The high morphological diversity may indicate a variety of niches being exploited by this family and may be a result of ecological opportunity.
Because similar species can exist together in the same geographic location, intraspecific competition may have forced these birds to occupy other niches and eventual diversification to prevent competitive exclusion.High variation in morphological traits that provide higher fitness in a niche and rapid divergence from a common ancestor are features often used to diagnose an adaptive radiation, but frequently are poorly quantified.
Because similar species can exist together in the same geographic location, intraspecific competition may have forced these birds to occupy other niches and eventual diversification to prevent competitive exclusion.High variation in morphological traits that provide higher fitness in a niche and rapid divergence from a common ancestor are features often used to diagnose an adaptive radiation, but frequently are poorly quantified.