Symposium proposal | |
Organizer: | Huabin Zhao (Wuhan University) |
Bats account for around 20% of extant mammal species and represent one of the world's most fascinating yet least-understood animals. They are mammals but possess many unique features distinctive from other mammals, such as powered flight, laryngeal echolocation, exceptional longevity, and sophisticated immune system conferring greater capacity to co-exist with many deadly viruses. Meanwhile, bats exhibit enormous diversity in diet, behaviour, and morphological and physiological traits. In this symposium, we attempt to share new discoveries to understand mechanisms underpinning the evolutionary innovations that have generated enormous diversity using bats as a model study group. |
S14-1
Bats as mammalian models for understanding dietary innovations
Stephen Rossiter1
1Department of Biology, Queen Mary University of London, London, UK
As a central selective force in evolution, the need to obtain food for energy production has driven morphological, sensory and metabolic innovations across the tree of life. Among vertebrates, the Neotropical leaf-nosed bats (Phyllostomidae) exhibit one of the most extreme cases of family-level diversification linked to diet. Lineages of this clade have evolved from a putative insectivorous ancestor to specialize on fruit, nectar, vertebrates, arthropods and blood. To determine whether these evolutionary transitions to contrasting diets have been accompanied by molecular adaptations underpinning different sets of genes and gene pathways, we performed genome-scale screens across 66 bat species. We find that phyllostomid lineages have indeed undergone pervasive positive selection in loci controlling the catabolism of different macromolecules. In particular, nectar-feeding bats show molecular adaptations in proteins underpinning the transport, breakdown, and shunting of carbohydrates, which together likely play roles in avoiding the toxic consequences of high blood sugar. By expanding our analyses to include nectar-feeding birds and Old World fruit bats, we also find strong evidence of parallel selection and molecular convergence for sugar metabolism. Our results suggest that metabolic adaptations have enabled multiple distantly related taxa to exploit a unique energy-rich dietary niche among vertebrates.
S14-2
The genomic basis of bats' extended longevity and tolerant immunity: Why should society care?
Emma Teeling1
1School of Biology and Environmental Science, University College Dublin, Ireland
Of all mammals, bat possess the most unique and peculiar adaptations that render them as excellent models to investigate the mechanisms of extended longevity and potentially halted senescence. Indeed, they are the longest-lived mammals relative to their body size, with the oldest bat caught being >41 years old, living approx. 8 times longer than expected. Bats defy the ‘rate-of-living’ theories that propose a positive correlation between body size and longevity as they use twice the energy as other species of considerable size, but live far longer. The mechanisms that bats use to avoid the negative physiological effects of their heightened metabolism and deal with an increased production of deleterious Reactive Oxygen Species (ROS) is not known, however it is suggested that they either prevent or repair ROS damage. Bats also appear to have resistance to many viral diseases such as rabies, SARS and Ebola and are the suspected reservoir species for a huge diversity of newly discovered viruses, including Sars-CoV-2 This suggests that their innate immunity is different to other mammals, perhaps playing a role in their unexpected longevity. Here the potential genomic basis for their rare immunity and exceptional longevity is explored across multiple bat genomes and divergent ageing and immune related markers (e.g. microbiome, telomeres, mitochondria, cellular dynamics, cytokine response) studied in wild bat populations. These findings provide a deeper understanding of the causal mechanisms of ageing and tolerant immunity, potentially uncovering the key molecular pathways that could be utilised to benefit society.
S14-3
Diversity in the Skies: The Molecular Ecology of #BatSenses
Liliana M. Dávalos1, Laurel R. Yohe1,2, Stephen J. Rossiter3, Kalina T. Davies3, Karen E. Sears4, Alexa Sadier4, Elizabeth R. Dumont5
1Stony Brook University
2Yale University
3Queen Mary University of London
4University of California, Los Angeles
5University of California, Merced
2Yale University
3Queen Mary University of London
4University of California, Los Angeles
5University of California, Merced
Despite their nocturnal habits, bats occupy virtually all terrestrial niches on Earth. Yet the molecular adaptations underlying this ecological diversity remain underexplored. Working with an international team for the better part of a decade, we have used amplicons, transcriptomes, hybrid probes, and more recently genomes to relate foraging and feeding ecology to sensory genes and pathways. We have found numerous, parallel instances of pseudogenization in vision and chemosensory genes, matching diversity of diet and olfactory receptors, the conservation of functional vomeronasal receptors since the K-t boundary in some lineages, and rampant preadaptation to divergent diets in sensory pathways. Our findings have upended the model of adaptation in response to ecological opportunities in the form of new diets, suggesting instead that shifts in foraging underlie much of the diversity we see today.
S14-4
Evolutionary genomics of bats: from phylogenetics to hosts of SARS-CoV-2
Xuming Zhou1
1Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
Bats (Chiroptera) are a group of mammals that possess many phenotype, such as flight, echolocation, exceptional longevity, that attracted biologists for decades. And, they are recognized as the hosts for many zoonotic diseases including the recent outbreak of COVID-19 pandemic. Recently, great progress has been made in resolving the status of Chiroptera and the relationships of within bats. In this talk, we first reports our phylogenetic analysis of 97 orthologs for 15 taxa, representing all laurasiatherian orders. Our reconstructions resolve the interordinal relationships within Laurasiatheria and corroborate the nesting of bats within Fereuungulata. Thus, Pegasoferae (Perissodactyla + Carnivora + Pholidota + Chiroptera) does not appear to be a natural group. Then, we compared the genomes of bats with other mammals and found a lack of CCAAT box in promoter of MTHFD1 could explain the low expression levels of this gene in bats leading to tolerate the infections. Finally, we constructed a rVSV-△G-G*-SARS2S pseudotyped virus, and performed viral infection analysis using cell lines and primary cells derived from 49 mammals (including 19 bats). The results showed that SASR-CoV-2 can infect a broad range of cells derived from different animals. Importantly, we found that Rhinolophus spp. is highly suspected to SARS-CoV-2 pseudotyped virus. These information provided a fundamental information about evolutionary history and characters as a host of bats.
S14-5
Evolution of sweet taste receptors and feeding ecology in bats
Hengwu Jiao1
1College of Life Sciences, Wuhan University, Wuhan, China
Bats represent the largest dietary radiation among all mammalian orders, with independent origins of frugivory, nectarivory, carnivory, omnivory, and even sanguivory, thus offering a unique model for investigating mechanisms underpinning dietary adaptations. Here we tested the association between feeding ecology and taste receptor evolution by examining the complete coding sequences of both sweet taste receptor genes (Tas1r2 and Tas1r3) in 34 representative bat species with contrasting diets. While these two genes are highly conserved between frugivorous and insectivorous bats at the sequence level, our behavioral experiments revealed that an insectivorous bat (Myotis ricketti) showed no preference for natural sugars, whereas the frugivorous species (Rousettus leschenaultii) showed strong preferences for sucrose and fructose. Furthermore, our cell-based assays revealed striking functional divergence: the sweet taste receptors of frugivorous bats are able to respond to natural sugars whereas those of insectivorous bats are not, which is consistent with the behavioral preference tests, suggesting that functional evolution of sweet taste receptors is closely related to diet. In the future, we plan to infer the ancestral states of sweet taste receptors at some key nodes of the species tree of vertebrates, such as the ancestral nodes of bats, placental mammals, amniotes, tetrapods, and vertebrates, and examine their functional changes in vitro using cell-based functional assays. Our future works will provide new insights into the origin and evolution of the sweet taste in vertebrates.