Search bioRxiv⌕ Search

bioRxiv · 10.1101/213124

Insights to the genetic etiology of a lifestyle-related disease with differential levels of severity using a hierarchy of common genetic variants

Abstract

Genome evolution in disparate species is synopsized to highlight the role of common genetic variants during their adaptation, and an evolutionary perspective is provided to infer lifestyle-related disease progression in humans. Cardiovascular disease (CVD) is a multi-factorial disease, where maladaptation due to a sedentary lifestyle and faulty diet can influence its prognosis, but the genetic basis for its differential severity remains unknown. As a healthy diet and lifestyle may restrict its prognosis, we hypothesize that a hierarchy of common genetic variants may differentially modulate that severity in a subpopulation. We suggest that the loss-of-function paradigm due to a genetic variant may give rise to a broad spectrum of CVD severity in conjunction with other variants. Here, we have inferred that CAD severity may be a consequence of the plasticity of common variants exclusive among patients with disparate disease severity. Most importantly, we have used a small and outbred subpopulation to demonstrate that common genetic variants can be exploited to trace this unique facet of CAD etiology. Moreover, we corroborate our hypothesis by reporting that a hierarchical plasticity of the LDLR gene, which has been implicated in a differential response to lipid metabolism, is associated with differential CVD severity.\n\nCan we gain insight to the genetic etiology of diseases using a limited number of genomes (few hundred)? Can small data sets lend insights that large data sets may subsequently confirm? Here, I show how common genetic variants, which were identified only from hundreds of individuals, may be used to gain unique insights regarding the disease etiology of a common lifestyle-related disease.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Fatakia, S. N.. 2017-11-02. Insights to the genetic etiology of a lifestyle-related disease with differential levels of severity using a hierarchy of common genetic variants. https://doi.org/10.1101/213124

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↗