Non-DSB Damage Clusters are Much More Frequent than DSBs in Galactic Cosmic Ray Exposures

Non-DSB Damage Clusters are Much More Frequent than DSBs in Galactic Cosmic Ray Exposures | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Non-DSB Damage Clusters are Much More Frequent than DSBs in Galactic Cosmic Ray Exposures Francis A. Cucinotta This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8466490/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In this paper for the first time the frequency of complex double strand breaks (DSB) and non-DSB clustered damage behind spacecraft and tissue shielding from exposure to galactic cosmic rays (GCR) and secondary radiation are predicted. Elementary DNA lesions produced by ionizing radiaiton include single strand breaks (SSB) and various forms of base damages (BD) (e.g. abasic or oxidative sites). Clustered DNA damage is defined by the occurence of 2 or more elementary lesions within 10 base-pairs (bp), and complex clustered damage as 3 or more elementary lesions within 10 bp. Clustered DNA damage is more difficult to repair compared to simple forms of DNA damage, while the relative contribution of clustered to simple DNA damage increases with ionizaton density or linear energy transfer (LET), and thefore imporant for space radiation exposures. The author has developed the multinominal model of clustered DNA damage that uses nanoscopic energy imparted spectra in DNA volumes and damage location probability operators to predict clustered DNA damage frequencies. In this paper, I combine the results of the multinomial model with GCR particle energy spectra to predict the probabilities of complex DSB, and tandem and bistranded non-DSB clustered damage. Predictions for the local interstellar (LIS), solar mininum, and solar maximum environments are discussed. Results show that the frequency of DSB and non-DSB clusters attenuates slowly with aluminum and tissue shielding, and that non-DSB clusters are more than 4 times more frequent than prompt DSBs. This is an important finding which quantifies the dominance of delayed formation of DSBs created in non-DSB clustered repair processes over promopt DSBs in the initial GCR DNA damage in tissues. Biophysics Astrobiology Systems Biology Galactic cosmic rays DNA damage high LET radiation heavy ions DSB and non-DSB damage clusters Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8466490","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":566419895,"identity":"2171c012-f1c3-459b-9a28-2daece3a0053","order_by":0,"name":"Francis A. 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radiation, heavy ions, DSB and non-DSB damage clusters","lastPublishedDoi":"10.21203/rs.3.rs-8466490/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8466490/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn this paper for the first time the frequency of complex double strand breaks (DSB) and non-DSB clustered damage behind spacecraft and tissue shielding from exposure to galactic cosmic rays (GCR) and secondary radiation are predicted. Elementary DNA lesions produced by ionizing radiaiton include single strand breaks (SSB) and various forms of base damages (BD) (e.g. abasic or oxidative sites). Clustered DNA damage is defined by the occurence of 2 or more elementary lesions within 10 base-pairs (bp), and complex clustered damage as 3 or more elementary lesions within 10 bp. Clustered DNA damage is more difficult to repair compared to simple forms of DNA damage, while the relative contribution of clustered to simple DNA damage increases with ionizaton density or linear energy transfer (LET), and thefore imporant for space radiation exposures. The author has developed the multinominal model of clustered DNA damage that uses nanoscopic energy imparted spectra in DNA volumes and damage location probability operators to predict clustered DNA damage frequencies. In this paper, I combine the results of the multinomial model with GCR particle energy spectra to predict the probabilities of complex DSB, and tandem and bistranded non-DSB clustered damage. Predictions for the local interstellar (LIS), solar mininum, and solar maximum environments are discussed. Results show that the frequency of DSB and non-DSB clusters attenuates slowly with aluminum and tissue shielding, and that non-DSB clusters are more than 4 times more frequent than prompt DSBs. This is an important finding which quantifies the dominance of delayed formation of DSBs created in non-DSB clustered repair processes over promopt DSBs in the initial GCR DNA damage in tissues.\u003c/p\u003e","manuscriptTitle":"Non-DSB Damage Clusters are Much More Frequent than DSBs\nin Galactic Cosmic Ray Exposures","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-06 06:40:42","doi":"10.21203/rs.3.rs-8466490/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"80236478-93ef-4b19-b705-f5a75e510027","owner":[],"postedDate":"January 6th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":60292773,"name":"Biophysics"},{"id":60292774,"name":"Astrobiology"},{"id":60292775,"name":"Systems Biology"}],"tags":[],"updatedAt":"2026-01-06T06:40:43+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-06 06:40:42","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8466490","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8466490","identity":"rs-8466490","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}