Biology subjects

Davies, J.

Publications and source records attributed to Davies, J..

5 recordsLinked to original sources

bioRxiv2018

Disease mortality in domesticated animals is predicted by host evolutionary relationships

Infectious diseases of domesticated animals impact human well-being via food insecurity, loss of livelihoods, and human infections. While much research has focused on parasites that infect single host species, most parasites of domesticated mammals infect multiple species. The impact of multi-host parasites varies across hosts; some rarely result in death, whereas others are nearly always fatal. Despite their high ecological and societal costs, we currently lack theory for predicting the lethality of multi-host parasites. Here, using a global dataset of over 4000 case-fatality rates for 65 infectious diseases (caused by micro and macro-parasites) and 12 domesticated host species, we show that the average evolutionary distance from an infected host to other mammal host species is a strong predictor of disease-induced mortality. We find that as parasites infect species outside of their documented phy-1 logenetic host range, they are more likely to result in lethal infections, with the odds of death doubling for each additional 10 million years of evolutionary distance. Our results for domesticated animal diseases reveal patterns in the evolution of highly lethal parasites that are difficult to observe in the wild, and further suggest that the severity of infectious diseases may be predicted from evolutionary relationships among hosts.

evolutionary biology↗

bioRxiv2018

The interaction of phylogeny and community structure: linking clades’ ecological structures and trait evolution

1AimCommunity phylogenetic studies use information about species evolutionary relationships to understand the processes of community ecological assembly. A central premise of the field is that species evolution maps onto ecological patterns, and phylogeny reveals something more than species traits alone. We argue, therefore, that there is a need to better understand and model the interaction of phylogeny with species traits and community composition.\n\nInnovationWe outline a new method that identifies clades with unusual ecological structures, based around partitioning the variation of species site occupancies ({beta}-diversity). Eco-phylogenetic theory would predict that these clades should also demonstrate distinct evolutionary trajectories. We suggest that modelling the evolution of independent trait data in these clades represents a strong test of whether there is an association between species ecological structure and evolutionary history.\n\nMain conclusionsUsing an empirical dataset of mammals from around the world, we identify two clades of rodents that tend not to co-occur (are phylogenetically overdispersed), and then find independent evidence of slower rates of body mass evolution in these clades. We suggest that our approach, which assumes nothing about the mode of species trait evolution but rather seeks to explain it using ecological information, presents a new way to examine eco-phylogenetic structure.

evolutionary biology↗

bioRxiv2017

Mammal extinctions and the increasing isolation of humans on the tree of life

A sixth great mass extinction is ongoing due to the direct and indirect effects of human pressures. However, not all lineages are impacted equally. As humans, we frequently believe that we hold a unique place on Earth. Here, we show that our current impacts on the natural world risk to heighten that expectation. Evolutionary proximity to Homo sapiens emerges as a powerful predictor of extinction risk among mammals. Our analysis shows that the species most closely related to H. sapiens are exposed to a large variety of threat types and that they may also have greater intrinsic sensitivity to threats. Pruning back the tree of life around us will lead to our species being among those with the fewest close relatives. We will erase our evolutionary history, forcing its uniqueness. If no action is taken, we will lose crucial biodiversity for the preservation of Earth ecosystems, and a key reference to what makes us human.

ecology↗

bioRxiv2017

A Liquid Chromatography-Mass Spectrometry Method For Screening Disulfide Tethering Fragments

We report the refinement of a high-throughput, liquid-chromatography/mass spectrometry (LC/MS)-based screening method for the identification of covalent small-molecule binders to proteins. Using a custom library of 1600 disulfide-capped fragments targeting surface cysteine residues, we optimize sample preparation, chromatography, and ionization conditions to maximize the reliability and flexibility of the approach. Data collection at a rate of 90 seconds per sample balances speed and reliability for sustained screening over multiple, diverse projects run over a 24-month period. The method is applicable to protein targets of various classes and a range of molecular masses. Data are processed in a custom pipeline that calculates a % bound value for each compound and detects false-positives by calculating significance of detected masses ( signal significance). An example pipeline has been made available through Biovias ScienceCloud Protocol Exchange. Data collection and analysis methods for the screening of covalent adducts of intact proteins are now fast enough to screen the largest covalent compound libraries in 1-2 days.

biophysics↗

bioRxiv2016

First Indications for Long-Term Benzodiazepine and Z-drugs use in the United Kingdom

Benzodiazepines and Z-drugs (BZDs), hypnotic drugs used for insomnia and anxiety, are prescribed millions of times a year in the UK. Although guidance from the relevant regulatory authorities (NICE and BNF) indicates them only for short-term use, the evidence suggests that many patients have been taking these drugs for much longer, often for decades. At present, there are no up-to-date, evidence-based estimates of the scale of long-term BZD use in the UK, which has prevented making a strong case for the need for withdrawal services. However, data obtained recently on BZD use from a number of GP surgeries (covering nearly 100,000 registered patients) in the North of England, allow such projections to be calculated. Scaling the results to a national level suggests that there are over a quarter of a million patients in the UK using BZDs for periods far longer than recommended. The projections also suggest that nearly half this number may be willing to accept help to stop their dependency on BZDs. These results indicate a serious problem, which should be addressed by more research into the harms associated with long-term BZD use, the provision of withdrawal services, and a national helpline to support patients with BZD dependency.

pharmacology and toxicology↗