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Individual shedder status and the origin of touch DNA

Jansson, Linda LU ; Swensson, Marie ; Gifvars, Emma ; Hedell, Ronny ; Forsberg, Christina ; Ansell, Ricky and Hedman, Johannes LU (2022) In Forensic Science International: Genetics 56.
Abstract

Due to improved laboratory techniques, touched surfaces and items are increasingly employed as sources of forensic DNA evidence. This has urged a need to better understand the mechanisms of DNA transfer between individuals. Shedder status (i.e. the propensity to leave DNA behind) has been identified as one major factor regulating DNA transfer. It is known that some individuals tend to shed more DNA than others, but the mechanisms behind shedder status are largely unknown. By comparing the amounts of DNA deposited from active hands (i.e. used “as usual”) and inactive hands (i.e. not allowed to touch anything), we show that some of the self-DNA deposited from hands is likely to have accumulated on hands from other parts of the body or... (More)

Due to improved laboratory techniques, touched surfaces and items are increasingly employed as sources of forensic DNA evidence. This has urged a need to better understand the mechanisms of DNA transfer between individuals. Shedder status (i.e. the propensity to leave DNA behind) has been identified as one major factor regulating DNA transfer. It is known that some individuals tend to shed more DNA than others, but the mechanisms behind shedder status are largely unknown. By comparing the amounts of DNA deposited from active hands (i.e. used “as usual”) and inactive hands (i.e. not allowed to touch anything), we show that some of the self-DNA deposited from hands is likely to have accumulated on hands from other parts of the body or previously handled items (active hands: 2.1 ± 2.7 ng, inactive hands: 0.83 ± 1.1 ng, paired t-test: p = 0.014, n = 27 pairs of hands). Further investigation showed that individual levels of deposited DNA are highly associated with the level of DNA accumulation on the skin of the face (Pearson's correlation: r = 0.90, p < 0.00001 and Spearman's ranked correlation: rs = 0.56, p = 0.0016, n = 29). We hypothesized that individual differences in sebum secretion levels could influence the amount of DNA accumulation in facial areas, but no such correlation was seen (Pearson's correlation: r = − 0.13, p = 0.66, n = 14). Neither was there any correlation between DNA levels on hands or forehead and the time since hand or face wash. We propose that the amount of self-DNA deposited from hands is highly influenced by the individual levels of accumulated facial DNA, and that cells/DNA is often transferred to hands by touching or rubbing one's face.

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author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
DNA deposition, DNA transfer, Forensic DNA analysis, Sebum, Shedder status
in
Forensic Science International: Genetics
volume
56
article number
102626
publisher
Elsevier
external identifiers
  • pmid:34781198
  • scopus:85118992878
ISSN
1872-4973
DOI
10.1016/j.fsigen.2021.102626
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2021 The Authors
id
7420c3cc-b598-4513-b889-085f723e6164
date added to LUP
2021-12-02 12:38:35
date last changed
2021-12-03 03:00:20
@article{7420c3cc-b598-4513-b889-085f723e6164,
  abstract     = {<p>Due to improved laboratory techniques, touched surfaces and items are increasingly employed as sources of forensic DNA evidence. This has urged a need to better understand the mechanisms of DNA transfer between individuals. Shedder status (i.e. the propensity to leave DNA behind) has been identified as one major factor regulating DNA transfer. It is known that some individuals tend to shed more DNA than others, but the mechanisms behind shedder status are largely unknown. By comparing the amounts of DNA deposited from active hands (i.e. used “as usual”) and inactive hands (i.e. not allowed to touch anything), we show that some of the self-DNA deposited from hands is likely to have accumulated on hands from other parts of the body or previously handled items (active hands: 2.1 ± 2.7 ng, inactive hands: 0.83 ± 1.1 ng, paired t-test: p = 0.014, n = 27 pairs of hands). Further investigation showed that individual levels of deposited DNA are highly associated with the level of DNA accumulation on the skin of the face (Pearson's correlation: r = 0.90, p &lt; 0.00001 and Spearman's ranked correlation: r<sub>s</sub> = 0.56, p = 0.0016, n = 29). We hypothesized that individual differences in sebum secretion levels could influence the amount of DNA accumulation in facial areas, but no such correlation was seen (Pearson's correlation: r = − 0.13, p = 0.66, n = 14). Neither was there any correlation between DNA levels on hands or forehead and the time since hand or face wash. We propose that the amount of self-DNA deposited from hands is highly influenced by the individual levels of accumulated facial DNA, and that cells/DNA is often transferred to hands by touching or rubbing one's face.</p>},
  author       = {Jansson, Linda and Swensson, Marie and Gifvars, Emma and Hedell, Ronny and Forsberg, Christina and Ansell, Ricky and Hedman, Johannes},
  issn         = {1872-4973},
  language     = {eng},
  publisher    = {Elsevier},
  series       = {Forensic Science International: Genetics},
  title        = {Individual shedder status and the origin of touch DNA},
  url          = {http://dx.doi.org/10.1016/j.fsigen.2021.102626},
  doi          = {10.1016/j.fsigen.2021.102626},
  volume       = {56},
  year         = {2022},
}