The Dávalos Lab conducts research on extinction and survival in deep time, genetics and genomics of non-model vertebrates, and deforestation.
Anna McPherran won the Williams award at the 2021 Ecology & Evolution retreat. The award will help Anna sequence the genomes of hutias!
Liliana M. Dávalos is Professor of Conservation Biology at Stony Brook University’s Department of Ecology and Evolution. Her research interests include molecular evolution, phylogenetics, and tropical conservation.
PhD in Ecology, Evolution,and Environmental Biology, 2004
Columbia University (New York, New York)
Certificate in Environmental Policy Studies, 2001
Columbia University (New York, New York)
BSc in Biology (emphasis on Genetics), 1997
Universidad del Valle (Cali, Colombia)
Taught evolution and researched molecular ecology
To investigate evolution and mechanisms of seasonal reversible size changes in a mammal.See notice
For outstanding teaching and true caring for students.
Symposia bring together outstanding young scientists to discuss exciting advances and opportunities in a broad range of disciplines.See profile
Data available to new students. Why are bats so likely to carry coronaviruses, yet seem little affected by them? Many studies have focused on their immune system, but there is much to learn about the cells viruses attack upon entry.
Data available to new students. All aspects of society have been upended by COVID-19. While most research has understandably focused on clinical applications, how the ancestors of SARS-CoV2 survive and circulate in nature is vital to both prevent future epidemics and help health professionals develop therapeutic treatments.
In support of RA Kristjan Mets. While scientific reaction to the COVID-19 pandemic has been swift, the risk of SARS-CoV-2 spilling back into native North American wildlife and feral domestic animals remains underexplored. Experimental infections of a variety of hosts, serological analyses of the cats in Wuhan, and cases of COVID-19 among tigers and lions in the Bronx Zoo, all have shown transmission back to wildlife and feral cats is highly probable. Tools are urgently needed to determine which of these animal populations are at greatest risk of establishing a native reservoir, and where the overlap with human populations is greatest. We propose to model the risk of spillover to animal populations and conversely the risk of future secondary spillover by combining models of molecular interaction between the virus and potential hosts, with multi- species Susceptible-Infectious-Recovered (SIR) models. Complementing decades of experience in vertebrate genomics (Dávalos) with expertise in epidemiology (Meliker), and spatial dynamics of wildlife disease (Mets), ours is the ideal team to quickly generate and test the necessary models to avert this risk.
To answer the question of how the shrew shrinks and then regrows its brain, we will establish this unusual species as a new model, by studying the biological, molecular, biochemical and genetic processes behind this reversible size change.
Data available for new students. We assembled a group of socio-environmental scientists to analyze and model the natural and human factors that determine the extinction and resilience of insular vertebrate fauna and leverage this understanding into metrics for use in conservation assessments.
We propose to develop a cross-scale research program that focuses on the relationships between phylogenetic diversity, genetic diversity and functional diversity of a biologically and economically important taxonomic group; bats.
Data available to new students. This project focuses on pairs of closely related bat species that sharply differ in their longevity. Detailed genome comparisons between closely related species with different life spans will test different theories of aging.
This training program responds to the challenges of new careers at the interface between science and decision making with an interdisciplinary set of new courses and a suite of activities united by the theme of “Scientific Training and Research to Inform DEcisions” (STRIDE).
Data available to new students. The project focuses on a relatively unexplored yet crucial aspect of plant-animal mutualisms; volatile chemical communication between plants and vertebrate frugivores.
Data available to new students. This project focuses on a diverse group of tropical bats in which various species evolved acute, specialized hearing, supersensitive eyes, the ability to smell subtle plant chemicals, or highly developed vomeronasal systems (thought to contribute to mating and social hierarchy).
The goal of this project was to discover the mechanisms underlying the survival of remnant populations in the WNS-affected area.
Noctilionoid bats comprise more than 200 species that span the entire ecological diversity of land mammals. They range from tiny insectivores and nectarivores to large carnivores, and even vampire bats. This is an unparalleled system for understanding how, when, and where bats evolved new diets, changed roosting habits and developed different kinds of echolocation. Together with the N. B. Simmons Lab, we are generating species-level phylogenies using molecular and morphological data, and including fossils of >20 extinct species. These phylogenies provide frameworks for investigating patterns and processes of ecological adaptation, speciation, and extinction across a hyperdiverse group of mammals.
The project will generate hypotheses about the evolutionary relationships of 5 different groups of bats, each containing at least one exclusively Antillean species. These evolutionary relationships will then be used to establish the timing and pattern of separation among bat species in the Antilles and their South and Central American relatives, and will also be compared with similar hypotheses about other terrestrial organisms. Drs. Nancy Simmons, Rob DeSalle, and Liliana Davalos will use standard methods for obtaining and analyzing morphological and molecular data from the study groups. Patterns of evolutionary relationships resulting from these data will be compared applying at least 5 different approaches.
Dietary adaptation is a major feature of phenotypic and ecological diversification, yet the genetic basis of dietary shifts is poorly understood. Among mammals, Neotropical leaf-nosed bats (family Phyllostomidae) show unmatched diversity in diet; from a putative insectivorous ancestor, phyllostomids have radiated to specialize on diverse food sources, including blood, nectar, and fruit. To assess whether dietary diversification in this group was accompanied by molecular adaptations for changing metabolic demands, we sequenced 89 transcriptomes across 58 species, and combined these with published data to compare ∼13,000 protein coding genes across 66 species. We tested for positive selection on focal lineages, including those inferred to have undergone dietary shifts. Unexpectedly, we found a broad signature of positive selection in the ancestral phyllostomid branch, spanning genes implicated in the metabolism of all major macronutrients, yet few positively selected genes at the inferred switch to plantivory. Branches corresponding to blood- and nectar-based diets showed selection in loci underpinning nitrogenous waste excretion and glycolysis, respectively. Intriguingly, patterns of selection in metabolism genes were mirrored by those in loci implicated in craniofacial remodelling, a trait previously linked to phyllostomid dietary specialisation. Finally, using simulations, we show that the widely-used branch-site model is likely to be misspecified, with the implication that it is too conservative and probably under-reports true cases of positive selection. Our findings point to a complex picture of adaptive radiation, in which the evolution of new dietary specialisations has been facilitated by early adaptations combined with the generation of new genetic variation.
Comprising more than 1400 species, bats possess adaptations unique among mammals including powered flight, unexpected longevity given small body size, and extraordinary immunity. Some of the molecular mechanisms underlying these unique adaptations includes DNA repair, metabolism and immunity. However, analyses have been limited to a few divergent lineages, reducing the scope of inferences on gene family evolution across the Order Chiroptera. We conducted an exhaustive comparative genomic study of 37 bat species encompassing a large number of lineages, with a particular emphasis on multi-gene family evolution across immune system and metabolic genes. In agreement with previous analyses, we found lineage-specific expansions of the APOBEC3 and MHC-I gene families, and loss of the proinflammatory PYHIN gene family. We inferred more than 1,000 gene losses unique to bats, including genes involved in the regulation of inflammasome pathways such as epithelial defense receptors, the natural killer gene complex and the interferon-gamma induced pathway. Gene set enrichment analyses revealed genes lost in bats are involved in defense response against pathogen-associated molecular patterns and damage-associated molecular patterns. Gene family evolution and selection analyses indicate bats have evolved fundamental functional differences compared to other mammals in both innate and adaptive immune system, with the potential to enhance anti-viral immune response while dampening inflammatory signaling. In addition, metabolic genes have experienced repeated expansions related to convergent shifts to plant-based diets. Our analyses support the hypothesis that, in tandem with flight, ancestral bats had evolved a unique set of immune adaptations whose functional implications remain to be explored.
Mammalian olfactory receptors (ORs) are a diverse family of genes encoding proteins that directly interact with environmental chemical cues. ORs evolve via gene duplication in a birth-death fashion, neofunctionalizing and pseudogenizing over time. Olfaction is a primary sense used for food detection in plant-visiting bats, but the relationship between dietary specialization and OR repertoires is unclear. Within neotropical Leaf-nosed bats (Phyllostomidae), many lineages are plant specialists, and some have a distinct OR repertoire compared to insectivorous species. Yet, whether specialization on particular plant genera is associated with the evolution of more specialized OR repertoires has never been tested. Using targeted sequence capture, we sequenced the OR repertoires of three sympatric species of short-tailed leaf-nosed bats (Carollia), which vary in their degree of specialization on the fruits of Piper plants. We characterized orthologous versus duplicated receptors among Carollia species, and identified orthologous receptors and associated paralogs to explore the diversity and redundancy of the receptor gene repertoire. The most dedicated Piper specialist, Carollia castanea, had lower OR diversity compared to the two more generalist species (sowelli, perspicillata), but we discovered a few unique sets of ORs within C. castanea with exceptional redundancy of similar gene duplicates. These unique receptors potentially enable C. castanea to detect Piper fruit odorants to an extent that the other species cannot. C. perspicillata, the species with the most generalist diet, had a larger diversity of functional receptors, suggesting the ability to detect a wider range of odorant molecules. The variation among ORs may be a factor in the coexistence of these sympatric species, facilitating the exploitation of different plant resources. Our study sheds light on how gene duplication plays a role in dietary adaptations and underlies patterns of ecological interactions between bats and plants.