Association between gene methylation and experiences of historical trauma in Alaska Native peoples
Open accessAbstract
BACKGROUND: Historical trauma experienced by Indigenous peoples of North America is correlated with health disparities and is hypothesized to be associated with DNA methylation. Massive group traumas such as genocide, loss of land and foodways, and forced conversion to Western lifeways may be embodied and affect individuals, families, communities, cultures, and health. This study approaches research with Alaska Native people using a community-engaged approach designed to create mutually-beneficial partnerships, including intentional relationship development, capacity building, and sample and data care. METHODS: A total of 117 Alaska Native individuals from two regions of Alaska joined the research study. Participants completed surveys on cultural identification, historical trauma (historical loss scale and historical loss associated symptoms scale), and general wellbeing. Participants provided a blood sample which was used to assess DNA methylation with the Illumina Infinium MethylationEPIC array. RESULTS: We report an association between historical loss associated symptoms and DNA methylation at five CpG sites, evidencing the embodiment of historical trauma. We further report an association between cultural identification and general wellbeing, complementing evidence from oral narratives and additional studies that multiple aspects of cultural connection may buffer the effects of and/or aid in the healing process from historical trauma. CONCLUSION: A community-engaged approach emphasizes balanced partnerships between communities and researchers. Here, this approach helps better understand embodiment of historical trauma in Alaska Native peoples. This analysis reveals links between the historical trauma response and DNA methylation. Indigenous communities have been stigmatized for public health issues instead caused by systemic inequalities, social disparities, and discrimination, and we argue that the social determinants of health model in Alaska Native peoples must include the vast impact of historical trauma and ongoing colonial violence.
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Trauma-related variation has been described in pathways relevant to neurodevelopment, immune-inflammatory signaling, circadian regulation, metabolism, and memory formation.
“Trauma-related variation has also been described in pathways relevant to neurodevelopment, immune-inflammatory signaling, circadian regulation, metabolism, and memory formation (7–9).”
From Epigenetic changes associated with multi-generational trauma: characterization, mechanisms, and therapeutics (2026) · cites this paper as [8]
The Results and Discussion sections on historical loss symptoms and differential DNA methylation describe associated genes involved in immune-system and metabolic pathways. They do not identify pathways for neurodevelopment, circadian regulation, or memory formation, and the Results state that no genes were significantly overrepresented in any biological pathway. Page numbers are unavailable in our copy. (LLM, conf=0.88)
Experimental — accuracy not yet measuredThese findings implicate coordinated variation across metabolic and regulatory pathways and have been associated with historical loss-related symptom reporting.
“These findings implicate coordinated variation across metabolic and regulatory pathways and have been associated with historical loss-related symptom reporting (8).”
From Epigenetic changes associated with multi-generational trauma: characterization, mechanisms, and therapeutics (2026) · cites this paper as [8]
The Results section reports five methylation sites significantly associated with historical loss-associated symptoms and identifies metabolic and regulatory-related pathways involving their genes. It also says no genes were significantly overrepresented in any pathway, so the paper does not establish coordinated variation across those pathways. (LLM, conf=0.86)
Experimental — accuracy not yet measuredGenome-wide analyses in Alaska Native communities have identified methylation differences in genes involved in mitochondrial metabolism, calcium transport, chromatin organization, and molecular trafficking.
“Genome-wide analyses in Alaska Native communities have identified methylation differences in genes involved in mitochondrial metabolism, calcium transport, chromatin organization, and molecular trafficking (8).”
From Epigenetic changes associated with multi-generational trauma: characterization, mechanisms, and therapeutics (2026) · cites this paper as [8]
Many investigations focus on historically defined trauma-exposed populations, including Holocaust survivors, Rwandan genocide survivors, and Alaska Native communities.
“Many investigations focus on historically defined trauma-exposed populations, including Holocaust survivors, Rwandan genocide survivors, and Alaska Native communities (8, 82, 98).”
From Epigenetic changes associated with multi-generational trauma: characterization, mechanisms, and therapeutics (2026) · cites this paper as [8]
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Cites
Aryee, M. J., Jaffe, A. E., Bravo, H. C., Ladd‐Acosta, C., Feinberg, A. P., Hansen, K. D., & Irizarry, R. A. (2014) · Bioinformatics · doi:10.1093/bioinformatics/btu049 · Cited by 4,423 · see citing works
DNA methylation arrays as surrogate measures of cell mixture distribution
Houseman, E. A., Accomando, W. P., Koestler, D. C., Christensen, B. C., Marsit, C. J., Nelson, H. H., Wiencke, J. K., & Kelsey, K. T. (2012) · BMC Bioinformatics · doi:10.1186/1471-2105-13-86 · Cited by 3,175 · see citing works
The Reactome Pathway Knowledgebase
Fabregat, A., Jupe, S., Matthews, L. R., Sidiropoulos, K., Gillespie, M. E., Garapati, P. V., Haw, R., Jassal, B., Korninger, F., May, B., et al. (2017) · Nucleic Acids Research · doi:10.1093/nar/gkx1132 · Cited by 2,798 · see citing works
The Reactome pathway Knowledgebase
Fabregat, A., Sidiropoulos, K., Garapati, P., Gillespie, M., Hausmann, K., Haw, R., Jassal, B., Jupe, S., Korninger, F., McKay, S., et al. (2016) · Nucleic Acids Research · doi:10.1093/nar/gkv1351 · Cited by 1,201 · see citing works
The American Indian Holocaust: Healing Historical Unresolved Grief
DeBruyn (1998) · American Indian and Alaska Native Mental Health Research · doi:10.5820/aian.0802.1998.60 · Cited by 1,030 · see citing works
De novo identification of differentially methylated regions in the human genome
Peters, T. J., Buckley, M. J., Statham, A. L., Pidsley, R., Samaras, K., Lord, R. V., Clark, S. J., & Molloy, P. L. (2015) · Epigenetics & Chromatin · doi:10.1186/1756-8935-8-6 · Cited by 956 · see citing works
Low-level processing of Illumina Infinium DNA Methylation BeadArrays
Triche, T. J., Weisenberger, D. J., Berg, D. V. D., Laird, P. W., & Siegmund, K. D. (2013) · Nucleic Acids Research · doi:10.1093/nar/gkt090 · Cited by 885 · see citing works
Preprocessing, normalization and integration of the Illumina HumanMethylationEPIC array with minfi
Fortin, J.-P., Triche, T. J., & Hansen, K. D. (2016) · Bioinformatics · doi:10.1093/bioinformatics/btw691 · Cited by 867 · see citing works
Methods for the Scientific Study of Discrimination and Health: An Ecosocial Approach
Krieger, N. (2012) · American Journal of Public Health · doi:10.2105/ajph.2011.300544 · Cited by 854 · see citing works
Brave Heart, M. Y. H., Chase, J., Elkins, J., & Altschul, D. B. (2011) · Journal of Psychoactive Drugs · doi:10.1080/02791072.2011.628913 · Cited by 825 · see citing works
Holocaust Exposure Induced Intergenerational Effects on FKBP5 Methylation
Yehuda, R., Daskalakis, N. P., Bierer, L. M., Bader, H. N., Klengel, T., Holsboer, F., & Binder, E. B. (2016) · Biological Psychiatry · doi:10.1016/j.biopsych.2015.08.005 · Cited by 782 · cited 1× · see citing works
“For example, the experience of historical trauma and DNA methylation was reported by Yehuda et al. (2016), identifying similar methylation patterns in Holocaust survivors and other similar patterns in their descendants [51].”
BackgroundConceptualizing and measuring historical trauma among American Indian people
Whitbeck, L. B., Adams, G. W., Hoyt, D. R., & Chen, X. (2004) · American Journal of Community Psychology · doi:10.1023/b:ajcp.0000027000.77357.31 · Cited by 751 · see citing works
(1998) · PubMed · Cited by 685 · see citing works
Bombay, A., Matheson, K., & Anisman, H. (2014) · Transcultural Psychiatry · doi:10.1177/1363461513503380 · Cited by 566 · see citing works
Epigenetic and immune function profiles associated with posttraumatic stress disorder
Uddin, M., Aiello, A. E., Wildman, D. E., Koenen, K. C., Pawelec, G., de los Santos, R., Goldmann, E., & Galea, S. (2010) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.0910794107 · Cited by 518 · see citing works
Self-citationA framework for enhancing ethical genomic research with Indigenous communities
Claw, K. G., Anderson, M. Z., Begay, R. L., Tsosie, K. S., Fox, K., Garrison, N. A., Bader, A. C., Bardill, J., Bolnick, D. A., Brooks, J. L., et al. (2018) · Nature Communications · doi:10.1038/s41467-018-05188-3 · Cited by 493 · see citing works
Self-citationHeart, M. Y. H. B. (1998) · Smith College Studies in Social Work · doi:10.1080/00377319809517532 · Cited by 453 · see citing works
Walters, K. L., Mohammed, S. A., Evans-Campbell, T., Beltrán, R. E., Chae, D. H., & Duran, B. (2011) · Du Bois Review: Social Science Research on Race · doi:10.1017/s1742058x1100018x · Cited by 424 · see citing works
Gone, J. P., Hartmann, W. E., Pomerville, A., Wendt, D. C., Klem, S. H., & Burrage, R. L. (2019) · American Psychologist · doi:10.1037/amp0000338 · Cited by 388 · see citing works
Whitbeck, B. L., Chen, X., Hoyt, D. R., & Adams, G. W. (2004) · Journal of Studies on Alcohol · doi:10.15288/jsa.2004.65.409 · Cited by 379 · see citing works
McCartney, D. L., Walker, R. M., Morris, S. W., McIntosh, A. M., Porteous, D. J., & Evans, K. L. (2016) · Genomics Data · doi:10.1016/j.gdata.2016.05.012 · Cited by 366 · see citing works
Mulligan, C., D'Errico, N., Stees, J., & Hughes, D. (2012) · Epigenetics · doi:10.4161/epi.21180 · Cited by 342 · see citing works
Guidance for DNA methylation studies: statistical insights from the Illumina EPIC array
Mansell, G., Gorrie-Stone, T. J., Bao, Y., Kumari, M., Schalkwyk, L. S., Mill, J., & Hannon, E. (2019) · BMC Genomics · doi:10.1186/s12864-019-5761-7 · Cited by 340 · see citing works
Healing the American Indian Soul Wound
Duran, E., Duran, B., Heart, M. Y. H. B., & Horse-Davis, S. Y. (1998) · International Handbook of Multigenerational Legacies of Trauma · doi:10.1007/978-1-4757-5567-1_22 · Cited by 332 · see citing works
The Indian Health Service and the Sterilization of Native American Women
Lawrence, J. (2000) · The American Indian Quarterly · doi:10.1353/aiq.2000.0008 · Cited by 315 · see citing works
BECon: a tool for interpreting DNA methylation findings from blood in the context of brain
Edgar, R. D., Jones, M. J., Meaney, M. J., Turecki, G., & Kobor, M. S. (2017) · Translational Psychiatry · doi:10.1038/tp.2017.171 · Cited by 261 · see citing works
Child abuse and epigenetic mechanisms of disease risk
Yang, B.-Z., Zhang, H., Ge, W., Weder, N., Douglas-Palumberi, H., Perepletchikova, F., Gelernter, J., & Kaufman, J. (2013) · American Journal of Preventive Medicine · doi:10.1016/j.amepre.2012.10.012 · Cited by 256 · see citing works
(2002) · PubMed Central · Cited by 251 · see citing works
Belzeaux-R, R., Bergon, A., Jeanjean, V., Loriod, B., Formisano‐Tréziny, C., Verrier, L., Loundou, A., Baumstarck, K., Boyer, L., Gall, V., et al. (2012) · Translational Psychiatry · doi:10.1038/tp.2012.112 · Cited by 222 · see citing works
RCP: a novel probe design bias correction method for Illumina Methylation BeadChip
Niu, L., Xu, Z., & Taylor, J. A. (2016) · Bioinformatics · doi:10.1093/bioinformatics/btw285 · Cited by 181 · see citing works
Internalized oppression: the psychology of marginalized groups
(2014) · Choice Reviews Online · doi:10.5860/choice.51-6454 · Cited by 171 · see citing works
Conching, A., & Thayer, Z. M. (2019) · Social Science & Medicine · doi:10.1016/j.socscimed.2019.04.001 · Cited by 162 · see citing works
A concurrent validational study of the NCHS General Well-Being Schedule.
Fazio, A. F. (1977) · PubMed · Cited by 145 · see citing works
Cultural trauma and epigenetic inheritance
Lehrner, A. L., & Yehuda, R. (2018) · Development and Psychopathology · doi:10.1017/s0954579418001153 · Cited by 128 · see citing works
Ehlers, C. L., Gizer, I. R., Gilder, D. A., Ellingson, J. M., & Yehuda, R. (2013) · Drug and Alcohol Dependence · doi:10.1016/j.drugalcdep.2013.05.011 · Cited by 119 · see citing works
Childhood adversity and DNA methylation in two population-based cohorts
Houtepen, L. C., Hardy, R., Maddock, J., Kuh, D. J., Anderson, E. L., Relton, C. L., Suderman, M. J., & Howe, L. D. (2018) · Translational Psychiatry · doi:10.1038/s41398-018-0307-3 · Cited by 110 · see citing works
shinyMethyl: interactive quality control of Illumina 450k DNA methylation arrays in R
Fortin, J.-P., Fertig, E. J., & Hansen, K. D. (2014) · F1000Research · doi:10.12688/f1000research.4680.2 · Cited by 108 · see citing works
Causal effect of smoking on DNA methylation in peripheral blood: a twin and family study
Li, S., Wong, E. M., Bui, M., Nguyen, T. L., Joo, J.-H. E., Stone, J., Dite, G. S., Giles, G. G., Saffery, R., Southey, M. C., et al. (2018) · Clinical Epigenetics · doi:10.1186/s13148-018-0452-9 · Cited by 103 · see citing works
Indigenous peoples and salmon stewardship: a critical relationship
Carothers, C., Black, J., Langdon, S. J., Donkersloot, R., Ringer, D., Coleman, J., Gavenus, E. R., Justin, W., Williams, M., Christiansen, F., et al. (2021) · Ecology and Society · doi:10.5751/es-11972-260116 · Cited by 103 · see citing works
the Traumatic Stress Brain Study Group, Logue, M. W., Miller, M. W., Wolf, E. J., Huber, B. R., Morrison, F. G., Zhou, Z., Zheng, Y., Smith, A. K., Daskalakis, N. P., et al. (2020) · Clinical Epigenetics · doi:10.1186/s13148-020-0820-0 · Cited by 102 · see citing works
Self-citationA Framework to Examine the Role of Epigenetics in Health Disparities among Native Americans
Brockie, T., Heinzelmann, M. M., & Gill, J. (2013) · Nursing Research and Practice · doi:10.1155/2013/410395 · Cited by 98 · see citing works
“I'm stronger than I thought”: Native women reconnecting to body, health, and place
Schultz, K., Walters, K. L., Beltran, R., Stroud, S., & Johnson-Jennings, M. (2016) · Health & Place · doi:10.1016/j.healthplace.2016.05.001 · Cited by 78 · see citing works
Hölscher, A. S., Schulz, W. A., Pinkerneil, M., Niegisch, G., & Hoffmann, M. J. (2018) · Clinical Epigenetics · doi:10.1186/s13148-017-0434-3 · Cited by 76 · see citing works
shinyMethyl: interactive quality control of Illumina 450k DNA methylation arrays in R
Fortin, J., Fertig, E. J., & Hansen, K. D. (2014) · F1000Research · doi:10.12688/f1000research.4680.1 · Cited by 69 · see citing works
Elm, J. H. L., Lewis, J., Walters, K. L., & Self, J. M. (2016) · Journal of Lesbian Studies · doi:10.1080/10894160.2016.1152813 · Cited by 63 · see citing works
Chaco Canyon Dig Unearths Ethical Concerns
Claw, K. G., Lippert, D., Bardill, J., Cordova, A., Fox, K., Yracheta, J., Bader, A. C., Bolnick, D. A., Malhi, R. S., TallBear, K., et al. (2017) · Human Biology · doi:10.13110/humanbiology.89.3.01 · Cited by 57 · see citing works
Self-citationSoto, C., Baezconde-Garbanati, L., Schwartz, S. J., & Unger, J. B. (2015) · Addictive Behaviors · doi:10.1016/j.addbeh.2015.06.005 · Cited by 56 · see citing works
Naumova, O. Y., Rychkov, S. Y., Kornilov, S. A., Odintsova, V. V., Олеговна, А. В., Solodunova, M. Y., Arintcina, I. A., Zhukova, M., Ovchinnikova, I. V., Burenkova, O. V., et al. (2019) · PLoS ONE · doi:10.1371/journal.pone.0214285 · Cited by 47 · see citing works
Tsosie, K. S., Begay, R. L., Fox, K., & Garrison, N. A. (2020) · Current Opinion in Genetics & Development · doi:10.1016/j.gde.2020.06.010 · Cited by 43 · see citing works
Chen, Y., Li, X., Kobayashi, I., Tsao, D., & Mellman, T. A. (2016) · Psychiatry Research · doi:10.1016/j.psychres.2016.07.045 · Cited by 26 · see citing works
Historical Loss: Implications for Health of American Indians in the Blackfeet Community
John‐Henderson, N. A., Oosterhoff, B. J., Kampf, T. D., Hall, B., Johnson, L. R., Laframboise, M. E., Malatare, M., Salois, E. M., Carter, J. R., & Adams, A. (2021) · Annals of Behavioral Medicine · doi:10.1093/abm/kaab032 · Cited by 14 · see citing works
(2009) · Duke University Press eBooks · doi:10.1215/9780822390831 · Cited by 11 · see citing works
Russian Colonization of Alaska
Grinëv, A. V. (2018) · UNP - Nebraska eBooks · doi:10.2307/j.ctv75d7t7 · Cited by 11 · see citing works
Fox, R., Neha, T. N., & Jose, P. E. (2021) · Figshare · doi:10.25455/wgtn.16527978 · Cited by 9 · see citing works
“Search for and Destroy”: US Army Relations with Alaska's Tlingit Indians and the Kake War of 1869
Jones, Z. R. (2013) · Ethnohistory · doi:10.1215/00141801-1816157 · Cited by 3 · see citing works
Kim, G., Aiello, A. E., Koenen, K. C., Galea, S., Wildman, D. E., & Uddin, M. (2019) · Biological Psychiatry · doi:10.1016/j.biopsych.2019.03.041 · Cited by 2 · see citing works
Self-citationEpigenetic mechanisms of resilience to psychopathology following trauma exposure
Bucknor, B. A. (2019) · Illinois Digital Environment for Access to Learning and Scholarship (University of Illinois at Urbana-Champaign) · Cited by 1 · see citing works
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Research works printed but not linked: 4
- [8]Walters KL Beltran R Huh D Evans-Campbell T Burton L Matthews S Leung M Kemp S Takeuchi D Dis-placement and Dis-ease: Land, Place, and Health Among American Indians and Alaska Natives Communities, Neighborhoods, and Health Social Disparities in Health and Health Care 2011 New York Springer 163 99
- [14]Sealaska Heritage Institute. Tribal members, military hold historic meeting on bombardments. Press Release. Juneau; 2020. Available from: https://www.sealaskaheritage.org/node/1170.
- [18]Mallonee M Selective justice: A crisis of missing and murdered Alaska native women Alaska Law Review 2021 38 93 120
- [25]Bader AC Carbaugh AE Bardill J Malhi RS Petzelt B Mitchell J Meloche CH Spake L Nichols KL Building relationships to shift accountability: Doing paleogenomic research with Indigenous nations and Ancestors Working with and for Ancestors: Collaboration in the Care and Study of Ancestral Remains 2020 1 London Routledge
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Anisman, H., Doubad, D., Asokumar, A., & Matheson, K. (2024) · Neuroscience & Biobehavioral Reviews · doi:10.1016/j.neubiorev.2024.105859 · Cited by 25 · see citing works
Adverse Childhood Experiences, Intergenerational Trauma, and Historical Trauma: A Child's Story.
Westby, C., Kokotek, L. E., & Washington, K. (2025) · Language, Speech & Hearing Services in Schools · doi:10.1044/2025_lshss-24-00123
Anisman, H., Bombay, A., & Matheson, K. (2025) · Frontiers in Environmental Health · doi:10.3389/fenvh.2025.1720326 · Cited by 4 · see citing works
Kac, E., Qi, Q., & Ryznar, R. (2026) · Frontiers in Psychiatry · doi:10.3389/fpsyt.2026.1769422 · Cited by 1 · see citing works
“Many investigations focus on historically de fi ned trauma-exposed populations, including Holocaust survivors, Rwandan genocide survivors, and Alaska Native communities (8, 82, 98).”
Wilson, K. T., Esposito, M. L., MacColl, C. D., Hammock, R., Pennewell, T., Dionne, A., & Garcia, A. N. (2025) · MedEdPORTAL · doi:10.15766/mep_2374-8265.11528 · Cited by 1 · see citing works
Iyanda, A., Adeleke, R., & Iyanda, O. F. (2025) · Addictive Behaviors Reports · doi:10.1016/j.abrep.2025.100639 · Cited by 1 · see citing works
Rusk, A. M. (2024) · CHEST Journal · doi:10.1016/j.chest.2023.12.009
Allen, H., & Cortés, Y. (2026) · Fourth World Journal · doi:10.63428/9w03xd25
The Psychology of South Asian Shame
Mirza, S., & Dhuffar-Pottiwal, M. (2026) · International and cultural psychology/International and cultural psychology series · doi:10.1007/978-3-032-16672-2_4
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- Authors
- Rogers-LaVanne, M. P., Bader, A. C., de Flamingh, A., Saboowala, S., Smythe, C., Atchison, B., Moulton, N., Wilson, A., Wildman, D. E., Boraas, A., Uddin, M., Worl, R., & Malhi, R. S.
- Affiliations
- University of Illinois Urbana-Champaign (US)
- Sealaska Heritage Institute (US)
- Navajo Language Academy (US)
- Heritage Foundation (US)
- University of South Florida (US)
- Corresponding author
- Malhi, Ripan S.
- Venue
- International Journal for Equity in Health
- Published
- 2023-09-08
- Volume
- 22
- Issue
- 1
- Pages
- 182-182
- ISSN
- 1475-9276 (ISSN-L)
- PMC
- PMC10485934
- OpenAlex
- W4386510931
- Cited by
- 10
- References
- 57
- Citations by year
- 2026: 4 · 2025: 4 · 2024: 2
- FWCI
- 2.70
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Locations
- International Journal for Equity in Health (publishedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Funders
- Directorate for Social, Behavioral and Economic Sciences (1620239)
- Topics
- Social Sciences › Health › Indigenous Health, Education, and Rights
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Epigenetics and DNA Methylation
- Social Sciences › Sociology and Political Science › Racial and Ethnic Identity Research
- Keywords
- historical trauma, DNA methylation, epigenetics, Alaska Natives, Indigenous health, cultural identification, well-being, historical loss, community-engaged research, social determinants of health, colonial violence, health disparities
- MeSH terms
- Stakeholder Participation, Historical Trauma, Indigenous Peoples, Alaska, Community Participation, Humans, Methylation
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