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Forensic Science International 172 (2007) 161–163 www.elsevier.com/locate/forsciint

Forensic : Usability of bryophyte material in forensic studies Viivi Virtanen *, Helena Korpelainen, Kirsi Kostamo Department of Applied . P.O. Box 27, FI-00014 University of Helsinki, Finland Received 27 June 2006; received in revised form 16 November 2006; accepted 19 November 2006 Available online 14 February 2007

Abstract Two experiments were performed to test the relevance of bryophyte (Plantae, Bryophyta) material for forensic studies. The first experiment was conducted to reveal if, and how well, fragments attach to footwear in general. In the test, 16 persons walked outdoors wearing rubber boots or hiking boots. After 24 h of use outdoors the boots were carefully cleaned, and all plant fragments were collected. Afterwards, all plant material was examined to identify the species. In the second experiment, fresh material of nine bryophyte species was kept in a shed in adverse conditions for 18 months, after which DNA was extracted and subjected to genotyping to test the quality of the material. Both experiments give support for the usability of bryophyte material in forensic studies. The bryophyte fragments become attached to shoes, where they remain even after the wearer walks on a dry road for several hours. Bryophyte DNA stays intact, allowing DNA profiling after lengthy periods following detachment from the original plant source. Based on these experiments, and considering the fact that many bryophytes are clonal , we propose that bryophytes are among the most usable plants to provide botanical evidence for forensic investigations. # 2007 Elsevier Ireland Ltd. All rights reserved.

Keywords: Bryophytes; DNA analysis; Forensic botany; Microsatellites; Plants

1. Introduction have reported a homicide investigation in which the fingerprinting of bryophytes was used to provide evidence in Forensic science has utilized different DNA fingerprinting a murder case. Bryophyte material found on the suspect’s car methods since the mid-1980s, when it was discovered that and clothes were successfully linked with bryophyte patches eukaryotic contain a large number of highly located at the crime scene. polymorphic sites [1]. Soon after DNA profiling had first been Recently, efforts to develop better and more reliable used to identify a murderer in England in 1986 [2],DNA methods to accurately utilize botanical evidence have been profiling of humans based on blood, hair, bone, saliva, semen initiated, mainly the development of microsatellite marker sets and other body tissues and products became a widely accepted for a number of common bryophyte species to allow precise and utilized forensic tool [3,4]. population genetic analyses and clone identification (Korpe- Although forensic DNA studies usually concern humans, lainen et al., in preparation) and a DNA sequence-based non-human DNA may also be employed. Animal DNA has identification system for grass species to determine the taxon of been examined to identify species subject to poaching, e.g., unknown grass samples [18]. Bryophytes are convenient for [5–7]. There are also homicide cases, in which DNA extracted forensic investigations as many of them are clonal and from cat or dog hair has been used as evidence [8,9]. However, common, their fragments can easily become attached to, molecular forensic botany is still an under-utilized field of e.g., shoes and clothes, and their DNA can be analyzed quite investigations [10]. Most common plant applications involve long after the plant has been fragmented. Correspondingly, the identification of specific plant varieties [11–13], and the grasses are plants frequently encountered by humans and many identification of suspected illegal plants, such as cannabis and of them are clonal. certain mushrooms [14–16]. Korpelainen and Virtanen [17] Clonal plant colonies usually consist of only one genotype, which can be identified with DNA markers and used as a piece of evidence in court when trying to link a suspect to a crime * Corresponding author. Tel.: +358 9 19158705; fax: +358 9 19158727. scene. In the homicide case reported by Korpelainen and E-mail address: viivi.virtanen@helsinki.fi (V. Virtanen). Virtanen [17], small particles of one of the studied

0379-0738/$ – see front matter # 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.forsciint.2006.11.012 162 V. Virtanen et al. / Forensic Science International 172 (2007) 161–163 bryophyte species found in the suspect’s car, apparently shape and cells was necessary for identification. For that, were transferred via shoes or clothes, clearly originated from the dissected from the stem and a slide for microscoping examination was prepared. The bryophytes were identified using a light microscope, e.g., Leitz 513 594 crime site in a forest, and another piece of bryophyte material with magnification from 10 (for studying leaves) to 40 (for studying cells) times. found on the suspect’s clothing was likely to have originated The identification of species was based on keys used in bryophyte floras (e.g., from the same site. [19]). Botanical evidence can be a useful tool for criminal investigations [17,10]. However, we lack the data on how well 2.3. Experiment 2: does bryophyte DNA stay intact in when plants, and different groups among them, attach to clothes or stored in a highly fluctuating environment? footwear. Besides, it is not adequately known how long DNA The persistence of DNA from nine bryophyte species (Table 2, one sample stays intact in fragmented plant material when detached from from each species) was studied by leaving fresh, moist plant material in paper the original source. In the present study, we aimed to test two bags in an unheated shed in southern Finland for 18 months, beginning aspects related to the use of bryophyte material as a forensic September 2003. During the period, the temperature varied between +25 8C 1 tool: (1) How likely it is to recover plant material, specifically and À28 8C. Afterwards, DNA was extracted using Qiagen DNeasy Plant bryophytes, from shoes after a person has been walking in a Mini Kit. Microsatellite PCR reactions were performed for one or three microsatellite loci per sample to test the quality of the DNA. Regular PCR forest, and (2) How well does bryophyte material, when amplification and successful genotyping were considered to be a sign of exposed to adverse environment, maintain its DNA intact satisfactory DNA quality. Genotyping was performed using fluorescently enough to allow DNA profiling. (FAM) labelled primer pairs developed for the bryophyte species in question (Korpelainen et al., unpublished). Amplifications were performed in 5 ml reactions, containing 0.5 ml DNA (about 5 ng, quantified visually from a 2. Materials and methods gel), 2.75 ml ddH2O, 0.5 ml10Â reaction buffer including 1.5 mM MgCl2, 0.1 ml dNTP mix (10mM), 0.15 ml DyNAzyme1 II DNA Polymerase (2 U/ml) 2.1. Description of bryophytes and 0.5 ml of both primers (5 pmol/ml). For genotyping, PCR-products were

first diluted with ddH2O. After that, 2 ml of each sample was pipetted into a Bryophytes are small plants that are typically 1–10 cm tall, but the species plate with 96 wells, and 8 ml of standard (MegaBACE ET400-R) diluted with TM sizes range from being microscopic to over a meter. They commonly grow close ddH2O (1:31) was added. The plates were then run with the MegaBACE together forming mats or patches on, e.g., ground, rock and . In the nature, 1000 DNA Analysis System. bryophytes occur in all environments except in the sea. They are rootless plants having stems with leaves, the stems ranging from single- to multi-branched. The structure of stems is quite fragile, and the shoots or fragments of the plants can 3. Results quite easily break off. Occasionally, the fragments form new plants, and the fragmentation is actually a means of vegetative . Because of the It was discovered that many of the shoes studied contained morphology and common occurrence of bryophytes in the nature in many areas, some amount of plant material despite the fact that the persons and the fact that many species grow on ground, the bryophyte shoots were expected to become attached to shoes and to be found on footwear in this participating in the study spent the last 4 h trekking on gravel experiment. or bitum-surfaced roads. Bryophytes were found on 9 out of 32 shoes (28%), altogether 22 shoots representing 5 species 2.2. Experiment 1: do bryophyte shoots get caught on shoes? (Table 1). Additionally, a few pine or spruce needles, and small pieces of grass and unidentifiable material Footwear from 16 persons participating in a field exercise were cleaned with werefoundonelevenshoes(34%). Most of the plant particles a heavy brush. The shoes were either hiking boots (14 pairs) or rubber boots were attached to the seams or laces or other upper parts of the (2 pairs). After 24 h of trekking in a forest and semi-urban environment (the last 4 h spent on gravel or paved roads), shoes were examined and sampled for all shoes. attached plant material. Afterwards, samples were studied under a light Bryophyte DNA extracted from samples stored for 18 microscope and the taxa were identified (Table 1) when possible. months in a fluctuating environment proved to work well in the All collected bryophyte material, including both fresh and dry specimens, were examined. Dried plants recovered their form on moistening. A study of Table 2 Species and microsatellite loci used when assessing the quality of bryophyte Table 1 DNA after exposure to adverse environment for 18 months Bryophyte species with numbers of shoots, and numbers of shoes from which bryophytes were found after a 24 h field exercise of 16 persons (altogether 32 Species Microsatellite Allele shoes) locus Species found Number of Number of shoes Aulacomnium palustre, Bog Groove- AUPA-1 140 bryophyte with shoots of AUPA-5 114 shoots found each species AUPA-7 84 Dicranum polysetum, Rugose 11 Brachythecium reflexum, Reflexed Feather-moss BRRE-5 124 Fork-moss Plagiochila asplenioides, Greater Feather-wort PLAS-4 64 Herzogiella seligeri, Silesian 11 Pleurozium schreberi, Red-stemmed Feather-moss PLSC-134 81 Feather-moss Polytrichum juniperinum, Juniper Haircap POJU-1 98 Hylocomium splendens, 11 Rhytidiadelphus squarrosus, Springy Turf-moss RHSQ-4 77 Glittering Wood-moss Rhytidiadelphus triquetrus, Big Shaggy-moss RHTR-1 77 Pleurozium schreberi, Red- 32 Rhizomnium punctatum, Dotted Thyme-moss RHPU-1 124 stemmed Feather-moss girgensohnii, Girgensohn’s Bog-moss SPGI-1 104 Sphagnum sp., Bog-moss 16 7 Alleles detected (the sizes of the amplification product as bp) are shown. V. Virtanen et al. / Forensic Science International 172 (2007) 161–163 163 microsatellite analysis conducted to test the quality of Appendix A. Supplementary data DNA and the success of genotyping. All samples listed in Table 2 gave an easily scorable result even though some of Supplementary data associated with this article can be found, the samples were partly moulded at the time of DNA in the online version, at doi:10.1016/j.forsciint.2006.11.012. extraction. References 4. Conclusion [1] A.J. Jeffreys, V. Wilson, S.L. Thein, Hypervariable ‘minisatellite’ regions in human DNA, Nature 14 (1985) 67–73. The present study demonstrates that plant material can be [2] P. Gill, D.J. Werrett, Exclusion of a man charged with murder by DNA found from the footwear of people who walk outdoors. fingerprinting, Forensic Sci. Int. 35 (1987) 145–148. Especially when strolling in forest or semi-urban areas, [3] J.L. 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