bioRxiv Science⌕ Search

bioRxiv · 10.1101/438226

Disease mortality in domesticated animals is predicted by host evolutionary relationships

Abstract

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.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Farrell, M. J., Davies, J.. 2018-10-08. Disease mortality in domesticated animals is predicted by host evolutionary relationships. https://doi.org/10.1101/438226

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Efficient growth factor production stabilizes cooperation in a cellular public goods game

Eukaryotic cells secrete growth factors that facilitate the proliferation and survival of neighboring cells in a coordinated manner essential for tissue development, repair, and homeostasis. However, mutant cells that fail to produce these factors may exploit the benefits provided by neighboring producers, thereby gaining a proliferative advantage that could lead to the extinction of the producer clone. Evolutionary theory predicts that preventing this "tragedy of the commons" requires a fixed spatial structure or other mechanisms that enable cells to interact preferentially with copies of themselves. Contrary to this expectation, we found that, in competition experiments, cells producing the diffusible growth factor interleukin-3 (IL3) resist invasion by non-producing mutant cells even in well-mixed populations, and that non-producers are driven to extinction instead. Using evolutionary game theory, we show that this outcome arises when the cost-to-benefit ratio of growth factor production falls below a critical threshold. We derive this tipping point analytically across the full parameter space of benefit function shape and group size and confirm that IL3 production in our experimental system satisfies this condition with a production cost less than 0.1% of the benefit conferred. These results demonstrate that efficient public good production alone can resolve the tragedy of the commons in populations of cells, and potentially in other biological systems.

evolutionary biology↗

Repeated Transitions in Migratory Behavior Across a Songbird Radiation Are Not Driven by Selection on Shared Variation in Candidate Genes

Understanding the mechanisms facilitating the repeated evolution of traits is a core question in evolutionary biology. While repeated evolution has been observed across many systems, behavioral phenotypes have been less well studied than morphological traits. Migration is a behavioral adaptation to seasonality that has evolved independently in many animals, and repeated gains and losses of migratory behavior have been especially prevalent throughout the diversification of birds. While migratory traits are heritable in many taxa and candidate genes underlying intraspecific variation in migratory behavior have been identified, whether similar genetic changes are responsible for the repeated evolution of migration remains poorly understood. We used a phylogenomic approach to investigate the relationship between variation in candidate genes and migratory propensity across nearly all species in the parulid warbler radiation (n = 101), a group of songbirds in which migratory behavior has been lost and gained multiple times. Comparisons of candidate gene tree topologies to the parulid warbler species tree revealed cases of discordance, though these were explained by differences in the number of phylogenetically informative sites among genes rather than by elevated genetic similarity among species sharing migratory strategies. Testing models of coding sequence evolution identified sites with elevated dN/dS in five candidate genes, suggestive of positive selection; however, variation at these sites showed no clear association with migratory strategy, nor did we detect recurrent selection across lineages where transitions in migratory behavior most likely occurred. Together, these results contradict the hypothesis that selection on shared variation (ancestral polymorphisms or introgressed alleles) facilitated the repeated evolution of migration in this clade.

evolutionary biology↗

Polygenic evolution towards a morning chronotype in modern humans

Chronotype is a behavioural phenotype, and its phenotypic trend is considered to change at higher latitudes. In the current study, we performed a polygenic assessment of chronotype trend using associated single nucleotide polymorphisms identified by a genome wide-association study. We found that the phenotypic trend towards morningness increased drastically during the migration of anatomically modern humans above 20 degrees north. Furthermore, two types of latitudinal selection of morningness alleles contributed to establishing the trend towards the morning chronotype at higher latitudes. We propose that the trend towards morningness is stronger in present-day modern humans living above 20 degrees north than in Neanderthals.

evolutionary biology↗