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Analysis of human genetic profiles from bite patterns in food and acts of suction of beverages, with the purpose of human identification

Abstract

The determination of identity is vital to human relationships, both social and legal level. The forensic dentistry contributes substantially to human identification, including the study of bite marks, since the teeth of an individual is unique. Therefore, is possible to match a bite mark to an individual who has a corresponding dentition. The analysis of human bite marks are made from biological and physical evidence. The physics is the measurement and determination of the pattern, size and shape of the teeth of a suspect by comparing them with the same characteristics observed in one bite. However, the bite marks may be distorted, hindering or preventing a proper comparison of the bite mark and the dentition that caused it, making it necessary to study the biological evidence, saliva, which is an extremely useful source of DNA in forensic cases. Since the cells from the saliva deposited on skin, objects or food, is possible to extract the DNA and to generate the genetic profile of the sample, promoting the identification of a suspect. Objective: To identify bite marks found in some food (cheese and chocolate)through three methods. Besides to obtain human genetic profiles of microsatellite marks through DNA extracted from saliva found in these food and beverage, after bite or suction, in order to apply in case of criminal investigation. Materials and Methods: The sample consists of 20 people, 10 male and 10 female, aging at least 18 years-old. Each participant will bite three chocolate bars and three pieces of cheese. The food is going to be analysed in different times (right after bite, after 3 days, and after 7 days have passed) and temperature (left at room temperature and refrigerator temperature). In this research reline technique will be used, using siliconas, wich consists of a casting with heavy material, followed by a second casting with fluid material. Through plaster molds of the suspects bitten and food, will be used to analyze the identifications bite marks correlating with models of the participants using three techniques: metric analysis (based on the Standards of ABFO - American Board of Forensci Odontology - scale nº 2); overlapping by transparency sheet and overlapping of digital images. In order to analyses the distances there will be used T Student statistic test. Saliva samples will be collected from 20 individuals, 10 males and 10 females, aged 18.Two fresh saliva samples will be collected from each subject,after biing six pieces of cheese, and six of chocolate, and drinking six bottles of water, reaching a total of twenty samples from each ofthe 20 members (400 samples in total). Ten samples of each individual will be left at room temperature in the climate of the city of Ribeirão Preto, São Paulo State, for different periods. And the other ten samples will be stored at refrigerator temperature (ranging from 2-4 ° C) for different periods of time. The DNA will be extracted according to the manufacturer QIAamp Kit (QIAGEN) protocol extraction. Amplification of the markers will be performed by human identification kit AmpFLSTR Identifiler PCR Amplification (CSF1P0, D2S1338, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D19S433, D21S11, FGA, TH01, TPOX, vWA, and amelogenin). Analysis of DNA fragments will be carried out in the ABI PRISM automated sequencer using the XL 3500 software Gene Mapper ® IDX. Statistical analysis will be performed by SPSS 12.0 (SPSS for Windons, SPSS Inc., Chicago, ILL, USA). (AU)