Who killed my dog? Use of forensic genetics to investigate an enigmatic case (original) (raw)
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Reviewing population studies for forensic purposes: Dog mitochondrial DNA
ZooKeys, 2013
The identification of dog hair through mtDNA analysis has become increasingly important in the last 15 years, as it can provide associative evidence connecting victims and suspects. The evidential value of an mtDNA match between dog hair and its potential donor is determined by the random match probability of the haplotype. This probability is based on the haplotype's population frequency estimate. Consequently, implementing a population study representative of the population relevant to the forensic case is vital to the correct evaluation of the evidence. This paper reviews numerous published dog mtDNA studies and shows that many of these studies vary widely in sampling strategies and data quality. Therefore, several features influencing the representativeness of a population sample are discussed. Moreover, recommendations are provided on how to set up a dog mtDNA population study and how to decide whether or not to include published data. This review emphasizes the need for improved dog mtDNA population data for forensic purposes, including targeting the entire mitochondrial genome. In particular, the creation of a publicly available database of qualitative dog mtDNA population studies would improve the genetic analysis of dog traces in forensic casework.
Dog mitochondrial genome sequencing to enhance dog mtDNA discrimination power in forensic casework
The identification of dog hair through mtDNA analysis has become increasingly important in the last 15 years, as it can provide associative evidence connecting victims and suspects. The evidential value of an mtDNA match between dog hair and its potential donor is determined by the random match probability of the haplotype. This probability is based on the haplotype’s population frequency estimate. Consequently, implementing a population study representative of the population relevant to the forensic case is vital to the correct evaluation of the evidence. This paper reviews numerous published dog mtDNA studies and shows that many of these studies vary widely in sampling strategies and data quality. Therefore, several features influencing the representativeness of a population sample are discussed. Moreover, recommendations are provided on how to set up a dog mtDNA population study and how to decide whether or not to include published data. This review emphasizes the need for improved dog mtDNA population data for forensic purposes, including targeting the entire mitochondrial genome. In particular, the creation of a publicly available database of qualitative dog mtDNA population studies would improve the genetic analysis of dog traces in forensic casework.
Forensic informativity of domestic dog mtDNA control region sequences
Forensic Science International, 2005
We have analysed the genetic information to be obtained from analysis of mitochondrial DNA (mtDNA) in domestic dogs studying the exclusion capacity in different populations and the correlation between mtDNA types and breeds or types of dogs. The exclusion capacities for a 573 bp sequence of the mitochondrial control region was between 0.86 and 0.95 for dogs in Sweden, the UK, Germany, Japan and China. The direct correlation between mtDNA type and breed, type of dog, and geographical origin of breed was generally low, but in some cases certain mtDNA types were overrepresented in one breed, and for wider groupings such as morphologically similar breeds, some mtDNA types were in many cases found in a distinct group of breeds, often originating from the same geographic region. This type of information may be used as an indication of the breed and, with some degree of probability, to include or exclude certain breeds from being the source of evidence materials.
DNA profile of dog feces as evidence to solve a homicide
Legal Medicine, 2016
Dog fecal samples were collected at the crime scene and from the shoes of the suspect to see whether they could be linked. DNA was genotyped using a 145 bp fragment containing a 60 bp hotspot region of the mitochondrial DNA (mtDNA) control region. Once the species origin was identified, sequences were aligned with the 23 canine haplotypes defined, showing that evidence and reference had 100% identity with haplotype 5. The frequency of haplotype 5 and the exclusion power of the reference population were 0.056 and 0.89, respectively. The forensic index showed that it was 20 times more likely that the evidence belonged to the reference dog than to some other unknown animal. The results support that the mtDNA hypervariable region 1 (HV1) is a good alternative for typing in trace or degraded casework samples when the STR panel fails, and demonstrate the utility of domestic animal samples to give additional information to solve human legal cases.
Journal of Forensic Sciences, 2008
The 608-bp hypervariable region 1 (HV1) sequences from 36 local dogs were analyzed to characterize the population genetic structure of canid mitochondrial DNA (mtDNA). Sixteen haplotypes were identified. A 417-bp segment of this sequence was compared with GenBank sequences from a geographically representative sample of 201 dogs, two coyotes, and two wolves. Sixty-six haplotypes were identified including 62 found only in domestic dogs. Fourteen of these correspond to the 16 local haplotypes and were among the most frequent haplotypes. The local sample was judged to be representative of the much broader geographic sample. No correlation was observed between local haplotypes and the owner's characterization of dog breed. A 60-bp variation ''hotspot'' within the canid HV1 was identified as a potentially valuable molecular tool, particularly for assaying limited or degraded DNA samples.
Forensic Science International-genetics, 2009
A voluntary collaborative exercise aiming at the mitochondrial analysis of canine biological samples was carried out in 2006-2008 by the Non-Human Forensic Genetics Commission of the Spanish and Portuguese Working Group (GEP) of the International Society for Forensic Genetics (ISFG). The participating laboratories were asked to sequence two dog samples (one bloodstain and one hair sample) for the mitochondrial D-loop region comprised between positions 15,372 and 16,083 using suggested primers and PCR conditions, and to compare their results against a reference sequence. Twenty-one participating laboratories reported a total of 67.5% concordant results, 15% non-concordant results, and 17.5% no results. The hair sample analysis presented more difficulty to the participants than the bloodstain analysis, with a high percentage (29%) failing to obtain a result. The high level of participation showed the interest of the community in the analysis of dog forensic samples but the results reveal that crucial methodological issues need to be addressed and further training is required in order to respond proficiently to the demands of forensic casework.
Forensic Science …, 2009
A voluntary collaborative exercise aiming at the mitochondrial analysis of canine biological samples was carried out in 2006-2008 by the Non-Human Forensic Genetics Commission of the Spanish and Portuguese Working Group (GEP) of the International Society for Forensic Genetics (ISFG). The participating laboratories were asked to sequence two dog samples (one bloodstain and one hair sample) for the mitochondrial D-loop region comprised between positions 15,372 and 16,083 using suggested primers and PCR conditions, and to compare their results against a reference sequence. Twenty-one participating laboratories reported a total of 67.5% concordant results, 15% non-concordant results, and 17.5% no results. The hair sample analysis presented more difficulty to the participants than the bloodstain analysis, with a high percentage (29%) failing to obtain a result. The high level of participation showed the interest of the community in the analysis of dog forensic samples but the results reveal that crucial methodological issues need to be addressed and further training is required in order to respond proficiently to the demands of forensic casework.
Non-human mtDNA helps to exculpate a suspect in a homicide case
International Congress Series, 2006
In January 2005 the dead body of a young female was found close to a highway in the south of Austria. Since the corpse had been set on fire using an accelerant, the victim has not been identified so far. Part of the sweater the woman was wearing was left and showed few short animal hairs. The investigations led the police to a young man who was already on remand due to a property offense. On the basis of morphological comparison, the hairs found on the sweater of the victim were suspected to derive either from an animal out of the group of minks and martens (Mustelidae) or from a dog (Canidae). Since hardly any of the hairs showed a root, mtDNA analysis had to be performed on the few hairs collected from the victim's sweater and on the hairs found in the suspect's car. The questions posed by the court were as follows: which species do the hairs on the sweater originate from, and secondly: do the hairs on the sweater and the hairs in the car belong to the same individual.
Mitochondrial DNA Analysis of the Domestic Dog: Control Region Variation Within and Among Breeds
Journal of Forensic Sciences, 2007
The mitochondrial DNA (mtDNA) control regions of 125 domestic dogs (Canis familiaris) encompassing 43 breeds, as well as one coyote and two wolves were sequenced and subsequently examined for sequence variation in an effort to construct a reference dog mtDNA data set for forensic analysis. Forty informative variable sites were identified that described 45 haplotypes, 29 of which were observed only once. Substantial variation was found both within and among breeds in the mtDNA derived from tissue, indicating that analysis of the mtDNA derived from dog hairs could be a valuable, discriminating piece of evidence in forensic investigations. The dog data set single nucleotide polymorphisms (SNPs) ranged from having one to six changes on a phylogenetic tree. On average, there were 1.9 character changes for each variable position on the tree. The most variable sites (with four or more changes each, listed from the most changes to the fewest) observed were 15,639 (L 5 6), 16,672 (L 5 5), 15,955 (L 5 4), 15,627 (L 5 3), 16,431 (L 5 3), and 16,439 (L 5 3). These sites were consistent with other reports on variable positions in the dog mtDNA genome. A total of 26 SNPs were chosen to best identify all major clusters in the domestic dog data set. The descriptive analyses revealed that this data set is similar to other published canine data sets and further demonstrates that this domestic dog data set is a useful resource for forensic applications. This reference data set has been compiled and validated against the published dog genetic literature with an aim to aid forensic investigations that seek to incorporate mtDNA sequences and SNPs from trace evidence such as dog hair.
DNA Profiling of Trace Evidence - Mitigating Evidence in a Dog Biting Case
trace evidence-mitigating evidence in a dog biting case. J ABSTRACT: A young girl was the victim of a severe dog atta An animal, suspected of having caused the attack, rvas later i pounded for investigation. Microclots of b1ood, recovered from dog's fur, were analyzed by STR DNA. Results showed that blood was not related to the biting. Other forensic evidence-ha fibers, and odontology-failed to connect a particular animal to attack. The implications of these findings for the dog and its ow are discussed as well as other forensic methods for resolving s CASES.