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McPherson CB, O'Donnell L, Moes E, Edgar H. No relationship found between dental fluctuating asymmetry, birthweight, and birth term in two modern North American samples. Am J Hum Biol 2024:e24114. [PMID: 38842218 DOI: 10.1002/ajhb.24114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/24/2024] [Accepted: 05/28/2024] [Indexed: 06/07/2024] Open
Abstract
OBJECTIVE Deciduous dental crowns primarily develop during gestation and early infancy and embody early life stress exposures. Composite measures of dental fluctuating asymmetry (DFA) generated from the deciduous teeth may therefore indicate cumulative gestational stress in developmental origins of health and disease (DOHaD) studies. This study examines whether higher composite measures of deciduous DFA are associated with low birthweight and prematurity, two aspects of birth phenotype consistently associated with increased morbidity and mortality risks in adulthood. SUBJECTS AND METHODS We evaluated associations between composite deciduous DFA, birthweight, and birth term in two contemporary North American samples: an autopsy sample from New Mexico (n = 94), and sample from a growth cohort study in Burlington, Ontario (n = 304). Dental metric data for each sample was collected from postmortem CT scans and dental casts, respectively. Composite DFA was estimated using buccolingual (BL) and mesiodistal (MD) crown diameters from paired deciduous teeth. RESULTS Contrary to expectations, the results of linear regression indicated no significant relationship between birthweight and DFA, or birth term and DFA, in either sample. CONCLUSIONS Deciduous DFA does not predict aspects of birth phenotype associated with gestational stress. Birthweight and birth term are plastic relative to the more developmentally stable deciduous dentition, which may only subtly embody early life stress. We suggest that deciduous DFA should be utilized with caution in DOHaD studies until its relationship with gestational stress is clarified.
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Affiliation(s)
- Cait B McPherson
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA
| | - Lexi O'Donnell
- College of Population Health, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
- Department of Anthropology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Emily Moes
- Department of Anthropology, University of New Mexico, Albuquerque, New Mexico, USA
- Department of Physician Assistant Studies, University of St. Francis, Albuquerque, New Mexico, USA
| | - Heather Edgar
- Department of Anthropology, University of New Mexico, Albuquerque, New Mexico, USA
- Office of the Medical Investigator, University of New Mexico, Albuquerque, New Mexico, USA
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2
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Andrade F, Howell L, Percival CJ, Richtsmeier JT, Marcucio RS, Hallgrímsson B, Cheverud JM. Genetic architecture of trait variance in craniofacial morphology. Genetics 2024; 226:iyae028. [PMID: 38386896 PMCID: PMC11090463 DOI: 10.1093/genetics/iyae028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 12/19/2023] [Accepted: 01/26/2024] [Indexed: 02/24/2024] Open
Abstract
The genetic architecture of trait variance has long been of interest in genetics and evolution. One of the earliest attempts to understand this architecture was presented in Lerner's Genetic Homeostasis (1954). Lerner proposed that heterozygotes should be better able to tolerate environmental perturbations because of functional differences between the alleles at a given locus, with each allele optimal for slightly different environments. This greater robustness to environmental variance, he argued, would result in smaller trait variance for heterozygotes. The evidence for Lerner's hypothesis has been inconclusive. To address this question using modern genomic methods, we mapped loci associated with differences in trait variance (vQTL) on 1,101 individuals from the F34 of an advanced intercross between LG/J and SM/J mice. We also mapped epistatic interactions for these vQTL in order to understand the influence of epistasis for the architecture of trait variance. We did not find evidence supporting Lerner's hypothesis, that heterozygotes tend to have smaller trait variances than homozygotes. We further show that the effects of most mapped loci on trait variance are produced by epistasis affecting trait means and that those epistatic effects account for about a half of the differences in genotypic-specific trait variances. Finally, we propose a model where the different interactions between the additive and dominance effects of the vQTL and their epistatic partners can explain Lerner's original observations but can also be extended to include other conditions where heterozygotes are not the least variable genotype.
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Affiliation(s)
- Fernando Andrade
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, USA
| | - Lisa Howell
- Department of Anthropology, Penn State University, University Park, PA 16802, USA
| | | | - Joan T Richtsmeier
- Department of Anthropology, Penn State University, University Park, PA 16802, USA
| | - Ralph S Marcucio
- Department of Orthopedic Surgery, School of Medicine, University of California San Francisco, San Francisco, CA 94110, USA
| | - Benedikt Hallgrímsson
- Department of Cell Biology and Anatomy, Cumming School of Medicine, Alberta Children's Hospital Research Institute and McCaig Bone and Joint Institute, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - James M Cheverud
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, USA
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Loy A, Ciucci P, Guidarelli G, Roccotelli E, Colangelo P. Developmental instability and phenotypic evolution in a small and isolated bear population. Biol Lett 2021; 17:20200729. [PMID: 33878275 DOI: 10.1098/rsbl.2020.0729] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We explored fluctuating asymmetry (FA) and morphological integration (MI) in the skull of the small, highly inbred and divergent Apennine bear (Ursus arctos marsicanus), to explore its uniqueness and investigate any potential effects of inbreeding depression. We used 3D geometric morphometrics contrasting Apennine bears with other two large outbred bear populations from Scandinavia and Kamchatka as controls. Shape divergence and variability were explored by a principal component analysis on aligned coordinates of 39 landmarks. Procrustes ANOVA, morphological disparity and the global integration index were used to explore FA, shape variance and MI. By remarking Apennine bears as a highly divergent phenotype, we recorded the highest FA and deviation from self-similarity compared with the other two control populations. We conclude that Apennine bears are likely facing developmental instability as a consequence of inbreeding depression, whereas the divergent trait covariance pattern may represent a potential source of evolutionary novelties. We discuss the implications for the conservation and management of this imperiled taxon.
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Affiliation(s)
- A Loy
- Envix Lab, Department of Biosciences and Territory, University of Molise, 86090 Pesche (IS), Italy
| | - P Ciucci
- Department of Biology and Biotechnologies 'Charles Darwin', University of Rome La Sapienza, 00185 Rome, Italy
| | - G Guidarelli
- Envix Lab, Department of Biosciences and Territory, University of Molise, 86090 Pesche (IS), Italy
| | - E Roccotelli
- Envix Lab, Department of Biosciences and Territory, University of Molise, 86090 Pesche (IS), Italy
| | - P Colangelo
- Research Institute on Terrestrial Ecosystems, National Research Council, 00015 Montelibretti, Rome, Italy
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Rau CD, Gonzales NM, Bloom JS, Park D, Ayroles J, Palmer AA, Lusis AJ, Zaitlen N. Modeling epistasis in mice and yeast using the proportion of two or more distinct genetic backgrounds: Evidence for "polygenic epistasis". PLoS Genet 2020; 16:e1009165. [PMID: 33104702 PMCID: PMC7644088 DOI: 10.1371/journal.pgen.1009165] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 11/05/2020] [Accepted: 10/02/2020] [Indexed: 12/22/2022] Open
Abstract
Background The majority of quantitative genetic models used to map complex traits assume that alleles have similar effects across all individuals. Significant evidence suggests, however, that epistatic interactions modulate the impact of many alleles. Nevertheless, identifying epistatic interactions remains computationally and statistically challenging. In this work, we address some of these challenges by developing a statistical test for polygenic epistasis that determines whether the effect of an allele is altered by the global genetic ancestry proportion from distinct progenitors. Results We applied our method to data from mice and yeast. For the mice, we observed 49 significant genotype-by-ancestry interaction associations across 14 phenotypes as well as over 1,400 Bonferroni-corrected genotype-by-ancestry interaction associations for mouse gene expression data. For the yeast, we observed 92 significant genotype-by-ancestry interactions across 38 phenotypes. Given this evidence of epistasis, we test for and observe evidence of rapid selection pressure on ancestry specific polymorphisms within one of the cohorts, consistent with epistatic selection. Conclusions Unlike our prior work in human populations, we observe widespread evidence of ancestry-modified SNP effects, perhaps reflecting the greater divergence present in crosses using mice and yeast. Many statistical tests which link genetic markers in the genome to differences in traits rely on the assumption that the same polymorphism will have identical effects in different individuals. However, there is substantial evidence indicating that this is not the case. Epistasis is the phenomenon in which multiple polymorphisms interact with one another to amplify or negate each other’s effects on a trait. We hypothesized that individual SNP effects could be changed in a polygenic manner, such that the proportion of as genetic ancestry, rather than specific markers, might be used to capture epistatic interactions. Motivated by this possibility, we develop a new statistical test that allowed us to examine the genome to identify polymorphisms which have different effects depending on the ancestral makeup of each individual. We use our test in two different populations of inbred mice and a yeast panel and demonstrate that these sorts of variable effect polymorphisms exist in 14 different physical traits in mice and 38 phenotypes in yeast as well as in murine gene expression. We use the term “polygenic epistasis” to distinguish these interactions from the more conventional two- or multi-locus interactions.
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Affiliation(s)
- Christoph D. Rau
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - Natalia M. Gonzales
- Department of Human Genetics, University of Chicago, Chicago, IL, United States of America
| | - Joshua S. Bloom
- Department of Human Genetics, UCLA, Los Angeles, CA, United States of America
| | - Danny Park
- Department of Medicine, UCSF, San Francisco, CA, United States of America
| | - Julien Ayroles
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, United States of America
| | - Abraham A. Palmer
- Department of Psychiatry, and Institute for Genomic Medicine, UCSD, San Diego, CA, United States of America
| | - Aldons J. Lusis
- Department of Human Genetics, UCLA, Los Angeles, CA, United States of America
| | - Noah Zaitlen
- Department of Neurology, UCLA, Los Angeles, CA, United States of America
- * E-mail:
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Genetic background dependent modifiers of craniosynostosis severity. J Struct Biol 2020; 212:107629. [PMID: 32976998 DOI: 10.1016/j.jsb.2020.107629] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 09/13/2020] [Accepted: 09/17/2020] [Indexed: 12/14/2022]
Abstract
Craniosynostosis severity varies in patients with identical genetic mutations. To understand causes of this phenotypic variation, we backcrossed the FGFR2+/C342Y mouse model of Crouzon syndrome onto congenic C57BL/6 and BALB/c backgrounds. Coronal suture fusion was observed in C57BL/6 (88% incidence, p < .001 between genotypes) but not in BALB/c FGFR2+/C342Y mutant mice at 3 weeks after birth, establishing that that the two models differ in phenotype severity. To begin identifying pre-existing modifiers of craniosynostosis severity, we compared transcriptome signatures of cranial tissues from C57BL/6 vs. BALB/c FGFR2+/+ mice. We separately analyzed frontal bone with coronal suture tissue from parietal bone with sagittal suture tissues because the coronal suture but not the sagittal suture fuses in FGFR2+/C342Y mice. The craniosynostosis associated Twist and En1 transcription factors were down-regulated, while Runx2 was up-regulated, in C57BL/6 compared to BALB/c tissues, which could predispose to craniosynostosis. Transcriptome analyses under the GO term MAPK cascade revealed that genes associated with calcium ion channels, angiogenesis, protein quality control and cell stress response were central to transcriptome differences associated with genetic background. FGFR2 and HSPA2 protein levels plus ERK1/2 activity were higher in cells isolated from C57BL/6 than BALB/c cranial tissues. Notably, the HSPA2 protein chaperone is central to craniofacial genetic epistasis, and we find that FGFR2 protein is abnormally processed in primary cells from FGFR2+/C342Y but not FGFR2+/+ mice. Therefore, we propose that differences in protein quality control responses may contribute to genetic background influences on craniosynostosis phenotype severity.
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Katz DC, Aponte JD, Liu W, Green RM, Mayeux JM, Pollard KM, Pomp D, Munger SC, Murray SA, Roseman CC, Percival CJ, Cheverud J, Marcucio RS, Hallgrímsson B. Facial shape and allometry quantitative trait locus intervals in the Diversity Outbred mouse are enriched for known skeletal and facial development genes. PLoS One 2020; 15:e0233377. [PMID: 32502155 PMCID: PMC7274373 DOI: 10.1371/journal.pone.0233377] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 05/04/2020] [Indexed: 02/06/2023] Open
Abstract
The biology of how faces are built and come to differ from one another is complex. Discovering normal variants that contribute to differences in facial morphology is one key to untangling this complexity, with important implications for medicine and evolutionary biology. This study maps quantitative trait loci (QTL) for skeletal facial shape using Diversity Outbred (DO) mice. The DO is a randomly outcrossed population with high heterozygosity that captures the allelic diversity of eight inbred mouse lines from three subspecies. The study uses a sample of 1147 DO animals (the largest sample yet employed for a shape QTL study in mouse), each characterized by 22 three-dimensional landmarks, 56,885 autosomal and X-chromosome markers, and sex and age classifiers. We identified 37 facial shape QTL across 20 shape principal components (PCs) using a mixed effects regression that accounts for kinship among observations. The QTL include some previously identified intervals as well as new regions that expand the list of potential targets for future experimental study. Three QTL characterized shape associations with size (allometry). Median support interval size was 3.5 Mb. Narrowing additional analysis to QTL for the five largest magnitude shape PCs, we found significant overrepresentation of genes with known roles in growth, skeletal and facial development, and sensory organ development. For most intervals, one or more of these genes lies within 0.25 Mb of the QTL's peak. QTL effect sizes were small, with none explaining more than 0.5% of facial shape variation. Thus, our results are consistent with a model of facial diversity that is influenced by key genes in skeletal and facial development and, simultaneously, is highly polygenic.
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Affiliation(s)
- David C. Katz
- Department of Cell Biology & Anatomy, Alberta Children’s Hospital Research Institute and McCaig Bone and Joint Institute, Cumming School of Medicine, University of Calgary, AB, Canada
| | - J. David Aponte
- Department of Cell Biology & Anatomy, Alberta Children’s Hospital Research Institute and McCaig Bone and Joint Institute, Cumming School of Medicine, University of Calgary, AB, Canada
| | - Wei Liu
- Department of Cell Biology & Anatomy, Alberta Children’s Hospital Research Institute and McCaig Bone and Joint Institute, Cumming School of Medicine, University of Calgary, AB, Canada
| | - Rebecca M. Green
- Department of Cell Biology & Anatomy, Alberta Children’s Hospital Research Institute and McCaig Bone and Joint Institute, Cumming School of Medicine, University of Calgary, AB, Canada
| | - Jessica M. Mayeux
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States of America
| | - K. Michael Pollard
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States of America
| | - Daniel Pomp
- Department of Genetics, University of North Carolina School of Medicine, Chapel Hill, NC, United States of America
| | - Steven C. Munger
- The Jackson Laboratory, Bar Harbor, ME, United States of America
| | | | - Charles C. Roseman
- Department of Evolution, Ecology, and Behavior, University of Illinois Urbana Champaign, Urbana, IL, United States of America
| | - Christopher J. Percival
- Department of Anthropology, Stony Brook University, Stony Brook, NY, United States of America
| | - James Cheverud
- Department of Biology, Loyola University Chicago, Chicago, IL, United States of America
| | - Ralph S. Marcucio
- Department of Orthopaedic Surgery, School of Medicine, University of California San Francisco, San Francisco, CA, United States of America
| | - Benedikt Hallgrímsson
- Department of Cell Biology & Anatomy, Alberta Children’s Hospital Research Institute and McCaig Bone and Joint Institute, Cumming School of Medicine, University of Calgary, AB, Canada
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Rahit KMTH, Tarailo-Graovac M. Genetic Modifiers and Rare Mendelian Disease. Genes (Basel) 2020; 11:E239. [PMID: 32106447 PMCID: PMC7140819 DOI: 10.3390/genes11030239] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 02/21/2020] [Indexed: 12/11/2022] Open
Abstract
Despite advances in high-throughput sequencing that have revolutionized the discovery of gene defects in rare Mendelian diseases, there are still gaps in translating individual genome variation to observed phenotypic outcomes. While we continue to improve genomics approaches to identify primary disease-causing variants, it is evident that no genetic variant acts alone. In other words, some other variants in the genome (genetic modifiers) may alleviate (suppress) or exacerbate (enhance) the severity of the disease, resulting in the variability of phenotypic outcomes. Thus, to truly understand the disease, we need to consider how the disease-causing variants interact with the rest of the genome in an individual. Here, we review the current state-of-the-field in the identification of genetic modifiers in rare Mendelian diseases and discuss the potential for future approaches that could bridge the existing gap.
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Affiliation(s)
- K. M. Tahsin Hassan Rahit
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada;
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Maja Tarailo-Graovac
- Departments of Biochemistry, Molecular Biology and Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada;
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
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Klingenberg CP. Phenotypic Plasticity, Developmental Instability, and Robustness: The Concepts and How They Are Connected. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00056] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Varón-González C, Pallares LF, Debat V, Navarro N. Mouse Skull Mean Shape and Shape Robustness Rely on Different Genetic Architectures and Different Loci. Front Genet 2019; 10:64. [PMID: 30809244 PMCID: PMC6379267 DOI: 10.3389/fgene.2019.00064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 01/24/2019] [Indexed: 12/20/2022] Open
Abstract
The genetic architecture of skull shape has been extensively studied in mice and the results suggest a highly polygenic and additive basis. In contrast few studies have explored the genetic basis of the skull variability. Canalization and developmental stability are the two components of phenotypic robustness. They have been proposed to be emergent properties of the genetic networks underlying the development of the trait itself, but this hypothesis has been rarely tested empirically. Here we use outbred mice to investigate the genetic architecture of canalization of the skull shape by implementing a genome-wide marginal epistatic test on 3D geometric morphometric data. The same data set had been used previously to explore the genetic architecture of the skull mean shape and its developmental stability. Here, we address two questions: (1) Are changes in mean shape and changes in shape variance associated with the same genomic regions? and (2) Do canalization and developmental stability rely on the same loci and genetic architecture and do they involve the same patterns of shape variation? We found that unlike skull mean shape, among-individual shape variance and fluctuating asymmetry (FA) show a total lack of additive effects. They are both associated with complex networks of epistatic interactions involving many genes (protein-coding and regulatory elements). Remarkably, none of the genomic loci affecting mean shape contribute these networks despite their enrichment for genes involved in craniofacial variation and diseases. We also found that the patterns of shape FA and individual variation are largely similar and rely on similar multilocus epistatic genetic networks, suggesting that the processes channeling variation within and among individuals are largely common. However, the loci involved in these two networks are completely different. This in turn underlines the difference in the origin of the variation at these two levels, and points at buffering processes that may be specific to each level.
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Affiliation(s)
- Ceferino Varón-González
- Institut de Systématique, Évolution, Biodiversité, ISYEB – UMR 7205 – CNRS, MNHN, UPMC, EPHE, UA, Muséum National d’Histoire Naturelle, Sorbonne Universités, Paris, France
- Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, Dijon, France
| | - Luisa F. Pallares
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, United States
| | - Vincent Debat
- Institut de Systématique, Évolution, Biodiversité, ISYEB – UMR 7205 – CNRS, MNHN, UPMC, EPHE, UA, Muséum National d’Histoire Naturelle, Sorbonne Universités, Paris, France
| | - Nicolas Navarro
- Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, Dijon, France
- EPHE, PSL University, Dijon, France
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