Genetically based low oxygen affinities of felid hemoglobins: Lack of biochemical adaptation to high-altitude hypoxia in the snow leopard

Genetically based modifications of hemoglobin (Hb) function that increase blood–O2 affinity are hallmarks of hypoxia adaptation in vertebrates. Among mammals, felid Hbs are unusual in that they have low intrinsic O2 affinities and reduced sensitivities to the allosteric cofactor 2,3-diphosphoglycerate (DPG). This combination of features compromises the acclimatization capacity of blood–O2 affinity and has led to the hypothesis that felids have a restricted physiological niche breadth relative to other mammals. In seeming defiance of this conjecture, the snow leopard (Panthera uncia) has an extraordinarily broad elevational distribution and occurs at elevations above 6000 m in the Himalayas. Here, we characterized structural and functional variation of big cat Hbs and investigated molecular mechanisms of Hb adaptation and allosteric regulation thatmay contribute to the extreme hypoxia tolerance of the snow leopard. Experiments revealed that purified Hbs from snow leopard and African lion exhibited equally low O2 affinities and DPG sensitivities. Both properties are primarily attributable to a single amino acid substitution, β2His→Phe, which occurred in the common ancestor of Felidae. Given the low O2 affinity and reduced regulatory capacity of feline Hbs, the extreme hypoxia tolerance of snow leopards must be attributable to compensatory modifications of other steps in the O2-transport pathway

Noninvasive genetic population survey of snow leopards (Panthera uncia) in Kangchenjunga conservation area, Shey Phoksundo National Park and surrounding buffer zones of Nepal

<p>Abstract</p> <p>Background</p> <p>The endangered snow leopard is found throughout major mountain ranges of Central Asia, including the remote Himalayas. However, because of their elusive behavior, sparse distribution, and poor access to their habitat, there is a lack of reliable information on their population status and demography, particularly in Nepal. Therefore, we utilized noninvasive genetic techniques to conduct a preliminary snow leopard survey in two protected areas of Nepal.</p> <p>Results</p> <p>A total of 71 putative snow leopard scats were collected and analyzed from two different areas; Shey Phoksundo National Park (SPNP) in the west and Kangchanjunga Conservation Area (KCA) in the east. Nineteen (27%) scats were genetically identified as snow leopards, and 10 (53%) of these were successfully genotyped at 6 microsatellite loci. Two samples showed identical genotype profiles indicating a total of 9 individual snow leopards. Four individual snow leopards were identified in SPNP (1 male and 3 females) and five (2 males and 3 females) in KCA.</p> <p>Conclusions</p> <p>We were able to confirm the occurrence of snow leopards in both study areas and determine the minimum number present. This information can be used to design more in-depth population surveys that will enable estimation of snow leopard population abundance at these sites.</p

Genetically based low oxygen affinities of felid hemoglobins: Lack of biochemical adaptation to high-altitude hypoxia in the snow leopard

Genetically based modifications of hemoglobin (Hb) function that increase blood–O2 affinity are hallmarks of hypoxia adaptation in vertebrates. Among mammals, felid Hbs are unusual in that they have low intrinsic O2 affinities and reduced sensitivities to the allosteric cofactor 2,3-diphosphoglycerate (DPG). This combination of features compromises the acclimatization capacity of blood–O2 affinity and has led to the hypothesis that felids have a restricted physiological niche breadth relative to other mammals. In seeming defiance of this conjecture, the snow leopard (Panthera uncia) has an extraordinarily broad elevational distribution and occurs at elevations above 6000 m in the Himalayas. Here, we characterized structural and functional variation of big cat Hbs and investigated molecular mechanisms of Hb adaptation and allosteric regulation thatmay contribute to the extreme hypoxia tolerance of the snow leopard. Experiments revealed that purified Hbs from snow leopard and African lion exhibited equally low O2 affinities and DPG sensitivities. Both properties are primarily attributable to a single amino acid substitution, β2His→Phe, which occurred in the common ancestor of Felidae. Given the low O2 affinity and reduced regulatory capacity of feline Hbs, the extreme hypoxia tolerance of snow leopards must be attributable to compensatory modifications of other steps in the O2-transport pathway

Methane, arsenic, selenium and the origins of the DMSO reductase family

Mononuclear molybdoenzymes of the dimethyl sulfoxide reductase (DMSOR) family catalyze a number of reactions essential to the carbon, nitrogen, sulfur, arsenic, and selenium biogeochemical cycles. These enzymes are also ancient, with many lineages likely predating the divergence of the last universal common ancestor into the Bacteria and Archaea domains. We have constructed rooted phylogenies for over 1,550 representatives of the DMSOR family using maximum likelihood methods to investigate the evolution of the arsenic biogeochemical cycle. The phylogenetic analysis provides compelling evidence that formylmethanofuran dehydrogenase B subunits, which catalyze the reduction of CO2 to formate during hydrogenotrophic methanogenesis, constitutes the most ancient lineage. Our analysis also provides robust support for selenocysteine as the ancestral ligand for the Mo/W atom. Finally, we demonstrate that anaerobic arsenite oxidase and respiratory arsenate reductase catalytic subunits represent a more ancient lineage of DMSORs compared to aerobic arsenite oxidase catalytic subunits, which evolved from the assimilatory nitrate reductase lineage. This provides substantial support for an active arsenic biogeochemical cycle on the anoxic Archean Earth. Our work emphasizes that the use of chalcophilic elements as substrates as well as the Mo/W ligand in DMSORs has indelibly shaped the diversification of these enzymes through deep time

Expert range maps of global mammal distributions harmonised to three taxonomic authorities

AimComprehensive, global information on species' occurrences is an essential biodiversity variable and central to a range of applications in ecology, evolution, biogeography and conservation. Expert range maps often represent a species' only available distributional information and play an increasing role in conservation assessments and macroecology. We provide global range maps for the native ranges of all extant mammal species harmonised to the taxonomy of the Mammal Diversity Database (MDD) mobilised from two sources, the Handbook of the Mammals of the World (HMW) and the Illustrated Checklist of the Mammals of the World (CMW).LocationGlobal.TaxonAll extant mammal species.MethodsRange maps were digitally interpreted, georeferenced, error-checked and subsequently taxonomically aligned between the HMW (6253 species), the CMW (6431 species) and the MDD taxonomies (6362 species).ResultsRange maps can be evaluated and visualised in an online map browser at Map of Life (mol.org) and accessed for individual or batch download for non-commercial use.Main conclusionExpert maps of species' global distributions are limited in their spatial detail and temporal specificity, but form a useful basis for broad-scale characterizations and model-based integration with other data. We provide georeferenced range maps for the native ranges of all extant mammal species as shapefiles, with species-level metadata and source information packaged together in geodatabase format. Across the three taxonomic sources our maps entail, there are 1784 taxonomic name differences compared to the maps currently available on the IUCN Red List website. The expert maps provided here are harmonised to the MDD taxonomic authority and linked to a community of online tools that will enable transparent future updates and version control

Molecular data suggests a Pliocene – Early Pleistocene divergence date for the common and pygmy hippopotamus

Hippopotamid phylogeny has proven difficult to resolve with proposed relationships between extant and fossil species receiving mixed levels of support. Of particular interest is the divergence between the two extant hippopotamid species, the well-known common hippopotamus (Hippopotamus amphibius) and the enigmatic pygmy hippopotamus (Choeropsis liberiensis). Previous studies have relied on morphological and fossil evidence to identify the ancestral species at the core of this divergence and its timing. In this study, we assembled a molecular matrix of 26 nuclear gene sequences from 11 ungulate species with two primates as an outgroup. We used a Bayesian relaxed molecular clock approach to reconstruct a calibrated time tree for Cetartiodactyla and estimate the divergence date between the common and pygmy hippopotamus. While previous morphological studies have estimated this event to have occurred sometime during the Late Miocene (between 11.6 and 5.3 million years ago), our nuclear gene-based estimates suggest a more recent split of about 4.04 Ma (95% confidence interval: 8.31–1.97 Ma) via RelTime-ML or 2.4 Ma (95% confidence interval: 3.1–1.6 Ma) via MCMCTree. These more recent estimates correspond with the Early Pliocene – Early Pleistocene sub-epochs and align most closely with the results of previous genomic studies. We discuss how our results compare with previous estimates based on both morphological and molecular studies, some of which extend the predicted range of this divergence date even further back in time. Our results suggest a different path of evolution for the understudied pygmy hippopotamus and reveal that morphological evidence alone may not resolve the correct hippopotamid phylogenetic and time trees. We suggest that the common and pygmy hippopotamus may be phylogenetically closer than once believed. Our results also call for further studies to develop a combined approach incorporating both molecular and morphological evidence to reach a consensus on the evolutionary patterns and timing that led to modern hippopotamid evolution

The Historical Biogeography of Mammalia

Palaeobiogeographic reconstructions are underpinned by phylogenies, divergence times and ancestral area reconstructions, which together yield ancestral area chronograms that provide a basis for proposing and testing hypotheses of dispersal and vicariance. Methods for area coding include multi-state coding with a single character, binary coding with multiple characters and string coding. Ancestral reconstruction methods are divided into parsimony versus Bayesian/likelihood approaches. We compared nine methods for reconstructing ancestral areas for placental mammals. Ambiguous reconstructions were a problem for all methods. Important differences resulted from coding areas based on the geographical ranges of extant species versus the geographical provenance of the oldest fossil for each lineage. Africa and South America were reconstructed as the ancestral areas for Afrotheria and Xenarthra, respectively. Most methods reconstructed Eurasia as the ancestral area for Boreoeutheria, Euarchontoglires and Laurasiatheria. The coincidence of molecular dates for the separation of Afrotheria and Xenarthra at approximately 100 Ma with the plate tectonic sundering of Africa and South America hints at the importance of vicariance in the early history of Placentalia. Dispersal has also been important including the origins of Madagascar\u27s endemic mammal fauna. Further studies will benefit from increased taxon sampling and the application of new ancestral area reconstruction methods

Pastoralism partnerships: Recognizing the value of local involvement in China\u27s snow leopard conservation efforts

Pastoralists are key stakeholders in environmental management decisions in China. Thus, their involvement in wildlife conservation and research is imperative for the success of long-term initiatives. Despite the many opportunities for herders to be included in these efforts, biases have hindered knowledge exchange and collaborative outcomes. This is detrimental for species living in quickly changing landscapes reliant on effective conservation, such as that of the snow leopard (Panthera uncia). Pastoralists living in snow leopard habitats on the Qinghai-Tibetan Plateau of China possess a deep and intricate understanding of the environments in which they live, and can serve as strong conservation allies by playing direct roles in scientific endeavors via expert elicitation and engagement. Here, we draw on our own experiences as academically trained scientists to present a framework for broadening opportunities for local community member participation in research efforts on the species. Framework outcomes include better targeting of conservation concerns, increased integration of Western science and local ecological knowledge, additional income to the community, clearer communication and trust between conservation stakeholders, greater flexibility in research, and additional platforms for community-based conservation. We outline avenues of involvement and considerations when working with local community members in snow leopard habitat, and submit this as an example with wide-ranging applicability to other parts of the world where livelihoods are intrinsically tied to the environment