Degradation of nuclear and mitochondrial DNA after γ-irradiation and its effect on forensic genotyping.

Goodwin, C; Wotherspoon, A; Gahan, ME; McNevin, D

Degradation of nuclear and mitochondrial DNA after γ-irradiation and its effect on forensic genotyping.

Goodwin, C Wotherspoon, A Gahan, ME McNevin, D

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Publisher:: Springer Science and Business Media LLC
Publication Type:: Journal Article
Citation:: Forensic science, medicine, and pathology, 2020
Issue Date:: 2020-07-12

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Field	Value	Language
dc.contributor.author	Goodwin, C
dc.contributor.author	Wotherspoon, A
dc.contributor.author	Gahan, ME
dc.contributor.author	McNevin, D https://orcid.org/0000-0003-1665-3367
dc.date.accessioned	2020-07-16T04:47:16Z
dc.date.available	2020-04-08
dc.date.available	2020-07-16T04:47:16Z
dc.date.issued	2020-07-12
dc.identifier.citation	Forensic science, medicine, and pathology, 2020
dc.identifier.issn	1547-769X
dc.identifier.issn	1556-2891
dc.identifier.uri	http://hdl.handle.net/10453/141786
dc.description.abstract	Forensic genotyping can be impeded by γ-irradiation of biological evidence in the event of radiological crime; that is, criminal activity involving radioactive material. Oxidative effects within the mitochondria of living cells elicits greater damage to mitochondrial DNA (mtDNA) than nuclear DNA (nuDNA) at low doses. This study presents a novel approach for the assessment of nuDNA versus mtDNA damage from a comparison of genotype and quantity data, while exploring likely mechanisms for differential damage after high doses of γ-irradiation. Liquid (hydrated) and dried (dehydrated) whole blood samples were exposed to high doses of γ-radiation (1-50 kilogray, kGy). The GlobalFiler PCR Amplification Kit was used to evaluate short tandem repeat (STR) genotyping efficacy and nuDNA degradation; a comparison was made to mtDNA degradation measured using real-time PCR assays. Each assay was normalized before comparison by calculation of integrity indices relative to unirradiated controls. Full STR profiles were attainable up to the highest dose, although DNA degradation was noticeable after 10 and 25 kGy for hydrated and dehydrated blood, respectively. This was manifested by heterozygote imbalance more than allele dropout. Degradation was greater for mtDNA than nuDNA, as well as for hydrated than dehydrated cells, after equivalent doses. Oxidative effects due to water radiolysis and mitochondrial function are dominant mechanisms of differential damage to nuDNA versus mtDNA after high-dose γ-irradiation. While differential DNA damage was reduced by cell desiccation, its persistence after drying indicates innate differences between nuDNA and mtDNA radioresistance and/or continued oxidative effects within the mitochondria.
dc.format	Print-Electronic
dc.language	eng
dc.publisher	Springer Science and Business Media LLC
dc.relation.ispartof	Forensic science, medicine, and pathology
dc.relation.isbasedon	10.1007/s12024-020-00251-2
dc.rights	info:eu-repo/semantics/openAccess
dc.rights	The final publication is available at Springer via http://dx.doi.org/ 10.1007/s12024-020-00251-2
dc.rights	This is a post-peer-review, pre-copyedit version of an article published in Forensic science, medicine, and pathology. The final authenticated version is available online at: https://dx.doi.org/10.1007/s12024-020-00251-2.	en_US
dc.rights	The final publication is available at Springer via http://dx.doi.org/ 10.1007/s12024-020-00251-2
dc.subject	1103 Clinical Sciences
dc.subject.classification	Legal & Forensic Medicine
dc.title	Degradation of nuclear and mitochondrial DNA after γ-irradiation and its effect on forensic genotyping.
dc.type	Journal Article
utslib.location.activity	United States
utslib.for	1103 Clinical Sciences
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Strength - CFS - Centre for Forensic Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Mathematical and Physical Sciences
pubs.organisational-group	/University of Technology Sydney
utslib.copyright.status	open_access	*
dc.date.updated	2020-07-16T04:47:11Z
pubs.publication-status	Published

Abstract:

Forensic genotyping can be impeded by γ-irradiation of biological evidence in the event of radiological crime; that is, criminal activity involving radioactive material. Oxidative effects within the mitochondria of living cells elicits greater damage to mitochondrial DNA (mtDNA) than nuclear DNA (nuDNA) at low doses. This study presents a novel approach for the assessment of nuDNA versus mtDNA damage from a comparison of genotype and quantity data, while exploring likely mechanisms for differential damage after high doses of γ-irradiation. Liquid (hydrated) and dried (dehydrated) whole blood samples were exposed to high doses of γ-radiation (1-50 kilogray, kGy). The GlobalFiler PCR Amplification Kit was used to evaluate short tandem repeat (STR) genotyping efficacy and nuDNA degradation; a comparison was made to mtDNA degradation measured using real-time PCR assays. Each assay was normalized before comparison by calculation of integrity indices relative to unirradiated controls. Full STR profiles were attainable up to the highest dose, although DNA degradation was noticeable after 10 and 25 kGy for hydrated and dehydrated blood, respectively. This was manifested by heterozygote imbalance more than allele dropout. Degradation was greater for mtDNA than nuDNA, as well as for hydrated than dehydrated cells, after equivalent doses. Oxidative effects due to water radiolysis and mitochondrial function are dominant mechanisms of differential damage to nuDNA versus mtDNA after high-dose γ-irradiation. While differential DNA damage was reduced by cell desiccation, its persistence after drying indicates innate differences between nuDNA and mtDNA radioresistance and/or continued oxidative effects within the mitochondria.

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