| 11. |
- Mendoza-Revilla, Javier, et al.
(författare)
-
Disentangling Signatures of Selection Before and After European Colonization in Latin Americans
- 2022
-
Ingår i: Molecular biology and evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 39:4
-
Tidskriftsartikel (refereegranskat)abstract
- Throughout human evolutionary history, large-scale migrations have led to intermixing (i.e., admixture) between previously separated human groups. Although classical and recent work have shown that studying admixture can yield novel historical insights, the extent to which this process contributed to adaptation remains underexplored. Here, we introduce a novel statistical model, specific to admixed populations, that identifies loci under selection while determining whether the selection likely occurred post-admixture or prior to admixture in one of the ancestral source populations. Through extensive simulations, we show that this method is able to detect selection, even in recently formed admixed populations, and to accurately differentiate between selection occurring in the ancestral or admixed population. We apply this method to genome-wide SNP data of ∼4,000 individuals in five admixed Latin American cohorts from Brazil, Chile, Colombia, Mexico, and Peru. Our approach replicates previous reports of selection in the human leukocyte antigen region that are consistent with selection post-admixture. We also report novel signals of selection in genomic regions spanning 47 genes, reinforcing many of these signals with an alternative, commonly used local-ancestry-inference approach. These signals include several genes involved in immunity, which may reflect responses to endemic pathogens of the Americas and to the challenge of infectious disease brought by European contact. In addition, some of the strongest signals inferred to be under selection in the Native American ancestral groups of modern Latin Americans overlap with genes implicated in energy metabolism phenotypes, plausibly reflecting adaptations to novel dietary sources available in the Americas.
|
|
| 12. |
- Price, Alkes L., et al.
(författare)
-
Discerning the ancestry of European Americans in genetic association studies
- 2008
-
Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 4:1
-
Tidskriftsartikel (refereegranskat)abstract
- European Americans are often treated as a homogeneous group, but in fact form a structured population due to historical immigration of diverse source populations. Discerning the ancestry of European Americans genotyped in association studies is important in order to prevent false-positive or false-negative associations due to population stratification and to identify genetic variants whose contribution to disease risk differs across European ancestries. Here, we investigate empirical patterns of population structure in European Americans, analyzing 4,198 samples from four genome-wide association studies to show that components roughly corresponding to northwest European, southeast European, and Ashkenazi Jewish ancestry are the main sources of European American population structure. Building on this insight, we constructed a panel of 300 validated markers that are highly informative for distinguishing these ancestries. We demonstrate that this panel of markers can be used to correct for stratification in association studies that do not generate dense genotype data.
|
|
| 13. |
- Trendafilova, Teodora, et al.
(författare)
-
Sodium-calcium exchanger-3 regulates pain “wind-up” : From human psychophysics to spinal mechanisms
- 2022
-
Ingår i: Neuron. - : Elsevier BV. - 0896-6273 .- 1097-4199. ; 110:16, s. 2571-2587.e13
-
Tidskriftsartikel (refereegranskat)abstract
- Repeated application of noxious stimuli leads to a progressively increased pain perception; this temporal summation is enhanced in and predictive of clinical pain disorders. Its electrophysiological correlate is “wind-up,” in which dorsal horn spinal neurons increase their response to repeated nociceptor stimulation. To understand the genetic basis of temporal summation, we undertook a GWAS of wind-up in healthy human volunteers and found significant association with SLC8A3 encoding sodium-calcium exchanger type 3 (NCX3). NCX3 was expressed in mouse dorsal horn neurons, and mice lacking NCX3 showed normal, acute pain but hypersensitivity to the second phase of the formalin test and chronic constriction injury. Dorsal horn neurons lacking NCX3 showed increased intracellular calcium following repetitive stimulation, slowed calcium clearance, and increased wind-up. Moreover, virally mediated enhanced spinal expression of NCX3 reduced central sensitization. Our study highlights Ca2+ efflux as a pathway underlying temporal summation and persistent pain, which may be amenable to therapeutic targeting.
|
|
| 14. |
- Volpi, Riccardo, et al.
(författare)
-
Modelling charge transport of discotic liquid-crystalline triindoles: the role of peripheral substitution
- 2017
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : ROYAL SOC CHEMISTRY. - 1463-9076 .- 1463-9084. ; 19:35, s. 24202-24208
-
Tidskriftsartikel (refereegranskat)abstract
- We have performed a multiscale approach to study the influence of peripheral substitution in the semiconducting properties of discotic liquid-crystalline triindoles. Charge carrier mobility as high as 1.4 cm(2) V-1 s(-1) was experimentally reported for triindoles substituted with alkynyl chains on the periphery (Gomez-Lor et al. Angew. Chem., Int. Ed., 2011, 50, 7399-7402). In this work, our goal is to get a deeper understanding of both the molecular electronic structure and microscopic factors affecting the charge transport properties in triindoles as a function of the spacer group connecting the central cores with the external alkyl chains (i.e., alkyne or phenyl spacers groups). To this end, we first perform Quantum Mechanical (QM) calculations to assess how the peripheral substitution affects the electronic structure and the internal reorganization energy. Secondly, boxes of stacked molecules were built and relaxed through molecular dynamics to obtain realistic structures. Conformational analysis and calculations of transfer integrals for closed neighbours were performed. Our results show that the insertion of ethynyl spacers between the central aromatic core and the flexible peripheral chains results in lower reorganization energies and enhanced intermolecular order within the stacks with a preferred cofacial 60 degrees staggered conformation, which would result in high charge-carrier mobilities in good agreement with the experimental data. This work allows a deeper understanding of charge carrier mobility in columnar phases, linking the structural order at the molecular level to the property of interest, i.e. the charge carrier mobility. We hope that this understanding will improve the design of systems at the supramolecular level aiming at obtaining a more defined conducting channel, higher mobility and smaller fluctuations within the column.
|
|
| 15. |
|
|
