| 1. |
- Choin, Jeremy, et al.
(författare)
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Genomic insights into population history and biological adaptation in Oceania
- 2021
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Ingår i: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 592:7855, s. 583-589
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Tidskriftsartikel (refereegranskat)abstract
- The Pacific region is of major importance for addressing questions regarding human dispersals, interactions with archaic hominins and natural selection processes(1). However, the demographic and adaptive history of Oceanian populations remains largely uncharacterized. Here we report high-coverage genomes of 317 individuals from 20 populations from the Pacific region. We find that the ancestors of Papuan-related ('Near Oceanian') groups underwent a strong bottleneck before the settlement of the region, and separated around 20,000-40,000 years ago. We infer that the East Asian ancestors of Pacific populations may have diverged from Taiwanese Indigenous peoples before the Neolithic expansion, which is thought to have started from Taiwan around 5,000 years ago(2-4). Additionally, this dispersal was not followed by an immediate, single admixture event with Near Oceanian populations, but involved recurrent episodes of genetic interactions. Our analyses reveal marked differences in the proportion and nature of Denisovan heritage among Pacific groups, suggesting that independent interbreeding with highly structured archaic populations occurred. Furthermore, whereas introgression of Neanderthal genetic information facilitated the adaptation of modern humans related to multiple phenotypes (for example, metabolism, pigmentation and neuronal development), Denisovan introgression was primarily beneficial for immune-related functions. Finally, we report evidence of selective sweeps and polygenic adaptation associated with pathogen exposure and lipid metabolism in the Pacific region, increasing our understanding of the mechanisms of biological adaptation to island environments.
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| 2. |
- Clave, Emmanuel, et al.
(författare)
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Human thymopoiesis is influenced by a common genetic variant within the TCRA-TCRD locus
- 2018
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Ingår i: Science Translational Medicine. - : American Association for the Advancement of Science (AAAS). - 1946-6234 .- 1946-6242. ; 10:457
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Tidskriftsartikel (refereegranskat)abstract
- The thymus is the primary lymphoid organ where naïve T cells are generated; however, with the exception of age, the parameters that govern its function in healthy humans remain unknown. We characterized the variability of thymic function among 1000 age- and sex-stratified healthy adults of the Milieu Intérieur cohort, using quantification of T cell receptor excision circles (TRECs) in peripheral blood T cells as a surrogate marker of thymopoiesis. Age and sex were the only nonheritable factors identified that affect thymic function. TREC amounts decreased with age and were higher in women compared to men. In addition, a genome-wide association study revealed a common variant (rs2204985) within the T cell receptor TCRA-TCRD locus, between the DD2 and DD3 gene segments, which associated with TREC amounts. Strikingly, transplantation of human hematopoietic stem cells with the rs2204985 GG genotype into immunodeficient mice led to thymopoiesis with higher TRECs, increased thymocyte counts, and a higher TCR repertoire diversity. Our population immunology approach revealed a genetic locus that influences thymopoiesis in healthy adults, with potentially broad implications in precision medicine.
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| 3. |
- Manry, Jérémy, et al.
(författare)
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The risk of COVID-19 death is much greater and age dependent with type I IFN autoantibodies.
- 2022
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 119:21
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Tidskriftsartikel (refereegranskat)abstract
- Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection fatality rate (IFR) doubles with every 5 y of age from childhood onward. Circulating autoantibodies neutralizing IFN-α, IFN-ω, and/or IFN-β are found in ∼20% of deceased patients across age groups, and in ∼1% of individuals aged <70 y and in >4% of those >70 y old in the general population. With a sample of 1,261 unvaccinated deceased patients and 34,159 individuals of the general population sampled before the pandemic, we estimated both IFR and relative risk of death (RRD) across age groups for individuals carrying autoantibodies neutralizing type I IFNs, relative to noncarriers. The RRD associated with any combination of autoantibodies was higher in subjects under 70 y old. For autoantibodies neutralizing IFN-α2 or IFN-ω, the RRDs were 17.0 (95% CI: 11.7 to 24.7) and 5.8 (4.5 to 7.4) for individuals <70 y and ≥70 y old, respectively, whereas, for autoantibodies neutralizing both molecules, the RRDs were 188.3 (44.8 to 774.4) and 7.2 (5.0 to 10.3), respectively. In contrast, IFRs increased with age, ranging from 0.17% (0.12 to 0.31) for individuals <40 y old to 26.7% (20.3 to 35.2) for those ≥80 y old for autoantibodies neutralizing IFN-α2 or IFN-ω, and from 0.84% (0.31 to 8.28) to 40.5% (27.82 to 61.20) for autoantibodies neutralizing both. Autoantibodies against type I IFNs increase IFRs, and are associated with high RRDs, especially when neutralizing both IFN-α2 and IFN-ω. Remarkably, IFRs increase with age, whereas RRDs decrease with age. Autoimmunity to type I IFNs is a strong and common predictor of COVID-19 death.
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| 4. |
- Patin, Etienne, et al.
(författare)
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Natural variation in the parameters of innate immune cells is preferentially driven by genetic factors
- 2018
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Ingår i: Nature Immunology. - : Springer Science and Business Media LLC. - 1529-2908 .- 1529-2916. ; 19, s. 302-314
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Tidskriftsartikel (refereegranskat)abstract
- The quantification and characterization of circulating immune cells provide key indicators of human health and disease. To identify the relative effects of environmental and genetic factors on variation in the parameters of innate and adaptive immune cells in homeostatic conditions, we combined standardized flow cytometry of blood leukocytes and genome-wide DNA genotyping of 1,000 healthy, unrelated people of Western European ancestry. We found that smoking, together with age, sex and latent infection with cytomegalovirus, were the main non-genetic factors that affected variation in parameters of human immune cells. Genome-wide association studies of 166 immunophenotypes identified 15 loci that showed enrichment for disease-associated variants. Finally, we demonstrated that the parameters of innate cells were more strongly controlled by genetic variation than were those of adaptive cells, which were driven by mainly environmental exposure. Our data establish a resource that will generate new hypotheses in immunology and highlight the role of innate immunity in susceptibility to common autoimmune diseases.
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| 5. |
- Piasecka, Barbara, et al.
(författare)
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Distinctive roles of age, sex, and genetics in shaping transcriptional variation of human immune responses to microbial challenges
- 2017
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Ingår i: Proceedings of the National Academy of Sciences. - 1091-6490. ; 115:3, s. 488-497
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Tidskriftsartikel (refereegranskat)abstract
- The contribution of host genetic and nongenetic factors to immunological differences in humans remains largely undefined. Here, we generated bacterial-, fungal-, and viral-induced immune transcriptional profiles in an age- and sex-balanced cohort of 1,000 healthy individuals and searched for the determinants of immune response variation. We found that age and sex affected the transcriptional response of most immune-related genes, with age effects being more stimulus-specific relative to sex effects, which were largely shared across conditions. Although specific cell populations mediated the effects of age and sex on gene expression, including CD8+ T cells for age and CD4+ T cells and monocytes for sex, we detected a direct effect of these intrinsic factors for the majority of immune genes. The mapping of expression quantitative trait loci (eQTLs) revealed that genetic factors had a stronger effect on immune gene regulation than age and sex, yet they affected a smaller number of genes. Importantly, we identified numerous genetic variants that manifested their regulatory effects exclusively on immune stimulation, including a Candida albicans-specific master regulator at the CR1 locus. These response eQTLs were enriched in disease-associated variants, particularly for autoimmune and inflammatory disorders, indicating that differences in disease risk may result from regulatory variants exerting their effects only in the presence of immune stress. Together, this study quantifies the respective effects of age, sex, genetics, and cellular heterogeneity on the interindividual variability of immune responses and constitutes a valuable resource for further exploration in the context of different infection risks or disease outcomes.
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| 6. |
- Scepanovic, Petar, et al.
(författare)
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A comprehensive assessment of demographic, environmental, and host genetic associations with gut microbiome diversity in healthy individuals
- 2019
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Ingår i: Microbiome. - : Springer Science and Business Media LLC. - 2049-2618. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The gut microbiome is an important determinant of human health. Its composition has been shown to be influenced by multiple environmental factors and likely by host genetic variation. In the framework of the Milieu Intérieur Consortium, a total of 1000 healthy individuals of western European ancestry, with a 1:1 sex ratio and evenly stratified across five decades of life (age 20-69), were recruited. We generated 16S ribosomal RNA profiles from stool samples for 858 participants. We investigated genetic and non-genetic factors that contribute to individual differences in fecal microbiome composition. RESULTS: Among 110 demographic, clinical, and environmental factors, 11 were identified as significantly correlated with α-diversity, ß-diversity, or abundance of specific microbial communities in multivariable models. Age and blood alanine aminotransferase levels showed the strongest associations with microbiome diversity. In total, all non-genetic factors explained 16.4% of the variance. We then searched for associations between > 5 million single nucleotide polymorphisms and the same indicators of fecal microbiome diversity, including the significant non-genetic factors as covariates. No genome-wide significant associations were identified after correction for multiple testing. A small fraction of previously reported associations between human genetic variants and specific taxa could be replicated in our cohort, while no replication was observed for any of the diversity metrics. CONCLUSION: In a well-characterized cohort of healthy individuals, we identified several non-genetic variables associated with fecal microbiome diversity. In contrast, host genetics only had a negligible influence. Demographic and environmental factors are thus the main contributors to fecal microbiome composition in healthy individuals. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT01699893.
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| 7. |
- Scepanovic, Petar, et al.
(författare)
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Human genetic variants and age are the strongest predictors of humoral immune responses to common pathogens and vaccines
- 2018
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Ingår i: Genome Medicine. - : Springer Science and Business Media LLC. - 1756-994X. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Humoral immune responses to infectious agents or vaccination vary substantially among individuals, and many of the factors responsible for this variability remain to be defined. Current evidence suggests that human genetic variation influences (i) serum immunoglobulin levels, (ii) seroconversion rates, and (iii) intensity of antigen-specific immune responses. Here, we evaluated the impact of intrinsic (age and sex), environmental, and genetic factors on the variability of humoral response to common pathogens and vaccines. Methods: We characterized the serological response to 15 antigens from common human pathogens or vaccines, in an age- and sex-stratified cohort of 1000 healthy individuals (Milieu Intérieur cohort). Using clinical-grade serological assays, we measured total IgA, IgE, IgG, and IgM levels, as well as qualitative (serostatus) and quantitative IgG responses to cytomegalovirus, Epstein-Barr virus, herpes simplex virus 1 and 2, varicella zoster virus, Helicobacter pylori, Toxoplasma gondii, influenza A virus, measles, mumps, rubella, and hepatitis B virus. Following genome-wide genotyping of single nucleotide polymorphisms and imputation, we examined associations between ~5 million genetic variants and antibody responses using single marker and gene burden tests. Results: We identified age and sex as important determinants of humoral immunity, with older individuals and women having higher rates of seropositivity for most antigens. Genome-wide association studies revealed significant associations between variants in the human leukocyte antigen (HLA) class II region on chromosome 6 and anti-EBV and anti-rubella IgG levels. We used HLA imputation to fine map these associations to amino acid variants in the peptide-binding groove of HLA-DRβ1 and HLA-DPβ1, respectively. We also observed significant associations for total IgA levels with two loci on chromosome 2 and with specific KIR-HLA combinations. Conclusions: Using extensive serological testing and genome-wide association analyses in a well-characterized cohort of healthy individuals, we demonstrated that age, sex, and specific human genetic variants contribute to inter-individual variability in humoral immunity. By highlighting genes and pathways implicated in the normal antibody response to frequently encountered antigens, these findings provide a basis to better understand disease pathogenesis.
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| 8. |
- Urrutia, Alejandra, et al.
(författare)
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Standardized Whole-Blood Transcriptional Profiling Enables the Deconvolution of Complex Induced Immune Responses
- 2016
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 16:10, s. 2777-2791
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Tidskriftsartikel (refereegranskat)abstract
- Systems approaches for the study of immune signaling pathways have been traditionally based on purified cells or cultured lines. However, in vivo responses involve the coordinated action of multiple cell types, which interact to establish an inflammatory microenvironment. We employed standardized whole-blood stimulation systems to test the hypothesis that responses to Toll-like receptor ligands or whole microbes can be defined by the transcriptional signatures of key cytokines. We found 44 genes, identified using Support Vector Machine learning, that captured the diversity of complex innate immune responses with improved segregation between distinct stimuli. Furthermore, we used donor variability to identify shared inter-cellular pathways and trace cytokine loops involved in gene expression. This provides strategies for dimension reduction of large datasets and deconvolution of innate immune responses applicable for characterizing immunomodulatory molecules. Moreover, we provide an interactive R-Shiny application with healthy donor reference values for induced inflammatory genes.
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| 9. |
- Vicente, Mário
(författare)
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Demographic History and Adaptation in African Populations
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Africa is the continent where modern humans originated and yet, African demographic history remains largely unknown. Through analyzing the genetic composition of extant and extinct individuals, it is possible to reveal signals of past demographic history and adaptation. In this thesis, I applied population genetic methods to investigate both deep African history and demographic changes associated with the migrations of farmers in Africa. While Paper I and II assess the genomic landscape before the arrival farming groups, Paper III, IV and V focus on the demographic patterns associated with the emergence of various African agro-pastoral societies and how shifts in ways of subsistence resulted in different selective pressures on the genomic level. The genomes from Southern African San hunter-gatherers harbor the earliest diverging lineages and represent the first population divergence event within the modern human phylogeny. However, gene-flow from farming groups has complicated the investigation of genetic relationships between different San groups. In Paper I, I established that Southern African hunter-gatherer genetic diversity fitted an isolation-by-distance model when genomic segments that trace their ancestry to farming groups were excluded. Paper II confirmed that all extant Southern African hunter-gatherers received admixture from farming groups, through comparison with ancient DNA data from three 2,000-year-old southern African Stone Age individuals. New date estimates for the first population divergence event in the modern human phylogeny, based on the Stone Age individuals, coincided with a period in the fossil record associated with transition between archaic humans into anatomically modern humans. Paper III assesses the genetic variation of four ancient Iron Age women from current-day South Africa. I was able to further refine their genetic profiles, which were closest related to southeast Bantu-speaking farmers from current-day South Africa. In Paper IV, I propose that the emergence of pastoralism in Southern Africa arrived through a male-driven migration of East African Afro-Asiatic related groups, who introduced their pastoral subsistence practices and livestock into Southern Africa. In Paper V, I investigated the history of the Fulani population and demonstrated how a shift in subsistence practice triggered different selective pressures in the Fulani. The pastoral Fulani from the Western Sahel show relatively high frequencies of the European-associated Lactase Persistence (LP) variant. Here, I propose that the LP mutation were introduced into Fulani genomes through contact with a North African group(s) who themselves carried European admixture. Additionally, by performing the first genome wide association study (GWAS) on the lactose digestion phenotype, I confirmed the association with the MCM6/LCT locus and identified a possible association between glycemic levels after lactose intake and the SPRY2 gene. Furthermore, in addition to the LP trait, I also identified other potential signals of local adaption related to the pastoralism lifeway of the Fulani. This thesis provided further insights on how the African genomic landscape was shaped through time, influenced by the environment, interactions between different groups and adaptations to different lifeways.
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