Animal Forensics
Under animal forensics , a merger is interdisciplinary methods of criminal biology , forensic veterinary medicine , track customer and forensics understood. Although this technical term has existed on an international level for over a decade, an adequate German term is not yet available.
In a narrower sense, animal forensics is understood to mean the examination of animal trace material which, in connection with a crime , can serve as evidence of a connection between perpetrator and victim . In a broader sense, animal forensics also refers to the investigation of animal trace material in crimes in which animals are directly involved as "those involved in the crime ".
A distinction must be made between those areas of forensic biology that deal with the analysis of animal trace material in criminal cases in which animals are neither "perpetrators" or victims, nor act as a direct link between those involved (e.g. the examination of corpse-eaten traces, forensic entomology and others).
Materials that can be examined include blood , hair and feathers , saliva , feces , urine , skin and mucous membrane samples , and other types of tissue . The most important method of animal forensics is DNA analysis ( "DNA forensics" ).
Historical developments
The inclusion and evaluation of animal trace material has gained significantly in importance in forensic examinations in recent years. The development of promising molecular genetic methods in the field of animal forensics was significantly influenced by groundbreaking advances in human genetics . This included the development of the polymerase chain reaction (PCR) in 1983 by Kary Mullis .
In 1984 Alec Jeffreys developed the " genetic fingerprint ", which uses unique features of the genetic makeup to uniquely identify individual individuals. A year later, the genetic fingerprint was used for the first time in court to clarify a criminal case. In 1988 it was also recognized as evidence by German courts . As early as 1987, this molecular genetic technique was adapted for use in animals and used to clarify controversial ancestry in dog breeding. Further advances, such as the use of specific DNA probes, ultimately led to the development of microsatellite analysis.
The usefulness of forensic DNA examinations depends on the general willingness of the judiciary to recognize DNA-based clues as evidence . In a sensational criminal case in 1995, a murderer was identified for the first time using the molecular genetic analysis of cat hair ( see below: The "Snowball" case ). Canine mitochondrial DNA analysis was first admitted as evidence at an evidence hearing in 1999 in the case of an attempted robbery in Texas .
Today, the use of DNA analyzes in forensics has become an integral part of police investigative work and courtrooms. Often it provides decisive evidence of a connection between perpetrator and victim. Using modern molecular genetic methods can now also many unresolved old cases thanks asservierter be reopened evidence. A progressive standardization and automation of laboratory and evaluation methodology in the analysis of animal material leads - similar to human forensics - to the establishment of extensive national and international reference databases, which on the one hand enable a quick comparison with genetic material already examined and on the other hand serve as a basis for statistical probability calculations can.
Investigation methods
The investigation of criminal offenses goes hand in hand with the molecular individualization of those involved and the possibility of individual assignment of traces . The primary goals pursued by animal forensics are the reliable identification and differentiation of the species , if necessary the clarification of the cause of death and, above all, the proof of a triangular relationship ("triangular connection") between perpetrator, victim and crime scene .
Although the use of proven methods such as histology , microscopy and comparative morphology and traditional forensic disciplines such as pathology , traumatology , odontology , ballistics and track customer remains indispensable, such offenses win in educating DNA-based methods are becoming increasingly important.
Basic diagnostic options based on forensic analyzes are species identification , race identification , identity verification and parentage controls .
Various methodological approaches can be considered for molecular biological evidence: Depending on the question, type, quality and quantity of the sample, both the nuclear genome (' nuclear ' nuclear DNA , nDNA) and the mitochondrial genome ( mitogenome , mtDNA) can be included in the investigation become.
RFLP analysis
This restriction fragment length polymorphism (RFLP) technique relies on the enzymatic cleavage of DNA by restriction endonucleases . The individual fragments are separated by means of gel electrophoresis and arranged on the gel according to their fragment length. The resulting lines ("bands") are z. B. made visible by hybridization techniques ( Southern blotting ). In principle, the RFLP can be used both for the analysis of the DNA of the cell nucleus and for the DNA of the mitochondria . In animal forensics , this method is used to determine the species in domestic and wild animals.
The use of the RFLP is one of the most original methods for forensic DNA analysis . The development of modern, more efficient analysis methods, however, let this technology take a back seat. Their disadvantage is the high initial amount of usable DNA required . Samples that have been negatively affected by environmental influences ( dirt , mold ), as are often found in connection with criminal offenses, are not suitable for this type of analysis.
Microsatellite analysis (genotyping)
Microsatellites or STRs ( short tandem repeats ) represent short, repetitive sections of DNA. The basic motif ( repeat ) is composed of 1-5 DNA building blocks ( nucleotides ) and is repeated an average of 10 to 50 times. Since the STRs generally do not carry any genetic information , are highly variable (high degree of polymorphism ), have a dense distribution in the genome and are inherited by both parents ( biparental ), they are predestined as independent markers for applications in many molecular genetic areas.
The high variability of the STR regions is used to create the individual genetic profile of an organism. This process is also known as "genotyping". The first microsatellite markers for dogs and cats were developed in the mid-1990s. Specific markers now exist for all domestic animals and numerous wild animal species. Originally used in parentage control, they have become useful tools for providing proof of identity in forensic medicine. In animal forensics , they are not only used for molecular individualization, but can also be used to identify species and to identify original populations (breed, school of fish ).
The STR analysis assumes the presence of nuclear DNA, whereby tiny amounts of biological trace material are sufficient for a successful reproduction of the DNA segments ( amplification ). This method is not suitable for samples with decomposed or missing nuclear DNA (old, autolytic tissue, hair with damaged or without hair roots).
Haplotyping
The mtDNA is not obtained from the cell nucleus , but from the mitochondria . Mitochondrial DNA analysis can be applied in areas where RFLP and genotyping fail. Hair found at crime scenes has mostly fallen out and no longer has an intact root. If only a few hairs with possibly damaged roots are available, the hair shaft can be used to isolate mitochondrial DNA, since the mtDNA - in contrast to the DNA of the cell nucleus - is present in thousands of copies per body cell.
For the forensic identification, an area of the mtDNA is examined, which is called the “ D-Loop ” ( displacement loop ), “Control region” or “Hypervariable region”. The analysis includes the duplication of the material with the polymerase chain reaction (PCR amplification) and the determination of the DNA sequence ( sequence analysis ) of the amplified area. The different sequence variants are called " haplotypes ".
Since the mtDNA of an organism comes exclusively from the mother, all animals of a maternal line share the same haplotype. This leads on the one hand to the fact that the reference samples can be made from animals that are related through the maternal line, but also means that the progeny of a line (z. B. litter sibling) with this method can not be separated from each other. Animals that are not related to one another can also have the same haplotype. Therefore, haplotyping can often only be used to exclude suspicious animals.
The mtDNA has proven to be a valuable tool for clarifying cases that have been considered unsolved for years. In addition to identifying individuals, sequencing the d-loop is also used to identify species.
Cytochrome b and rRNA
The gene segments for cytochrome b and rRNA are also located in the mitochondrial genome. In contrast to the control region already mentioned, these are information-bearing sections of the genetic make-up (“coding elements”) that are considered to be almost unchangeable (“conserved”). Here, variations in the sequence of genetic information (sequence variations) are only observed between individual species.
Both areas, both cytochrome b and rRNA, have been widely used in phylogenetic studies; H. in studies of the evolution of animal species and enable a reliable identification of the species. The analysis consists of an amplification of selected DNA segments (PCR amplification) combined with the above-mentioned RFLP technique or direct DNA sequencing . Comprehensive reference databases are required for both methods. These can be privately or internationally accessible. One example is the Basic Local Alignment Search Tool ( BLAST ) at the National Center for Biotechnology Information (NCBI).
Methods for sex determination ( sex determination )
On the basis of tissue adhering to torn hair, it is in principle possible to determine the sex - via the coloration of the sex-specific chromatin in the follicle cells ; however, it is not used in the routine.
Current methods for determining sex are based on the detection of genetic information sequences (sequences) or markers that are only present on one of the two sex chromosomes (including the SRy gene on the Y chromosome, x-chromosomal microsatellites). It is also possible to detect genes that are located on both sex chromosomes and that have different forms, such as e.g. B. have fragment lengths (amelogenin gene in ruminants). The determination of gender from meat, blood or hair samples is used in forensics in nature and species protection as well as in the food sector . It serves as evidence of poaching and fraud.
Trace material used
hair
Comparative morphology , microscopy and histology are classic methods in the field of forensic hair analysis . The type, number and state of preservation of the hair that has been seized influence their value as trace material.
Every mammalian species has hair with a characteristic length, color and root structure as well as specific morphological features. A hair consists of the hair root and the hair shaft, which is basically made up of the marrow, bark and cuticle .
In animals there are guide, trunk, guard, fur and guard hair, downy and woolly hair, bristles , long hair ( tail , mane ), eyelashes and whiskers . The hair of different parts of the body of the same individual can show considerable variability .
The structure of the pith and cuticle of the hair is strictly species-specific. It therefore also allows a reliable distinction between humans and animals. The structure of the marrow cells , the thickness of the marrow and its continuity ("marrow ray"), the number of marrow cell layers and the thickness ratio of hair pith to hair cortex serve as criteria for the precise determination of the species . In addition, the content and distribution of pigments as well as the surface profile of the cuticle cells can be analyzed.
Due to the regression of the roots, natural hair loss mainly takes place in a phase in which hair growth is dormant (“ telogenic phase ”). Because loose hair can be easily transferred to other individuals or objects, it is the main source of forensic hair marks. But hair loss can also take place in active growth stages, e.g. B. by getting caught on an object. A microscopic analysis of the hair root allows not only the determination of the growth phase, but also a distinction between “pulled out” and “failed”.
The concrete analysis of an animal hair first includes the assignment of the species based on its species-specific morphology. Subsequently, the “comparison microscopy ” procedure - the use of two light microscopes connected by an optical bridge - allows the hair in question to be assessed simultaneously with a hair sample of known origin. The latter usually comes from a reference sample collection or is the comparison sample of a suspicious animal. If the examined hair has microscopic properties that match the reference, this results in a common origin for both hairs.
Classical microscopy thus enables species, race , hair type and hair status to be determined; However, animal hair generally does not have sufficiently individual morphological properties to be able to be assigned to a certain individual with absolute certainty.
Molecular genetic tests based on analyzes of both nuclear and mitochondrial DNA can provide more precise clues as to the possible origin of a hair .
blood
The classic analysis of blood, the blood group serology , the determination of serum proteins and isoenzymes as well as the characterization of MHC - antigens . Originally they were used for parentage checks.
From the mid-1990s, the use of modern molecular genetic methods led to the displacement of conventional methods. The reasons for this were an improved probability of exclusion , easier automation and easier standardization of the evaluation.
The current analysis possibilities of blood encompass the whole range of molecular genetic methods. The DNA is obtained from the nucleated white blood cells . The choice of the respective analysis method depends on the quantity and quality of the sample available. The examination of blood plays a role
- Parentage controls (e.g. to control the specified parent animals),
- Proof of identity (e.g. to identify a stolen animal)
- Bite attacks between animals (to identify the animals involved),
- Animal bite attacks on humans (to identify the perpetrator),
- Poaching (e.g. to determine whether a protected animal species has been killed),
- Accidents (e.g. in accidents with wildlife caused by tracks on the vehicle).
saliva
Traces of saliva are regularly found in connection with bite attacks against humans or animals. They are used to identify and transfer suspicious offender animals.
For molecular genetic analyzes, the DNA is isolated from the epithelial cells of the oral mucosa contained in the saliva . The method of choice for studies is short tandem repeat typing.
A contamination of the saliva with blood or hair of the victim can be problematic . Nevertheless, research has found a positive correlation between the increasing severity of the bite wounds and the success rate in isolating the culprit's DNA from saliva.
Bones and tissues
Tissue samples of various kinds, including those from animal products , are routinely analyzed , especially in wildlife forensics and in the forensic examination of food . In addition, the examination of tissue samples is usually necessary in connection with homicides that are contrary to animal welfare.
All molecular genetic methods can be used, depending on the preservation status of the sample. Methods for molecular genetic determination of species and tissue types are predominantly used.
Semen, feces and urine
In contrast to human forensics, the molecular genetic analysis of sperm in animals hardly plays a role. It is mainly used in the area of parentage controls. In the literature it has only been used to date when there is suspicion of sexual assault by animals.
While the examination of urine, etc. a. in controversial doping cases, which sometimes occurs, the examination of feces is so far of no practical importance.
Animals in Forensic Biology
Animals as victims
Crimes in which animals are victimized primarily include theft , cruelty to animals and homicides .
The tasks in this area include
- the genetic characterization of animal trace material,
- the identification of individual individuals using reference material,
- Evidence of criminal acts on the basis of crime scene traces,
- Clarification of the perpetrator's identity (traces left by the perpetrator that can be proven to come from the victim).
The correspondence of traces of DNA on weapons (e.g. knife , projectile ) with the victim's DNA, determined with the help of the DNA profile, can help to clarify these questions . The same applies to the comparison of other animal remains (e.g. blood, hair, bones) with reference samples.
In the case of pets, such comparison samples can often be obtained afterwards by collecting hair from brushes or blankets. A complete lack of reference DNA from the individual himself can even be compensated for by a DNA analysis of the parents : the identity of the victim can also be clarified in this way by proving a close relationship. For example, stolen cattle can be clearly identified using a STR analysis of the specified dams.
Domestic, farm and zoo animals
In a case report from Argentina, cattle were stolen from a ranch and slaughtered. The carcasses found later could be clearly identified by their branding. Their DNA profiles were compared with pieces of meat seized from a butcher's shop. Evidence and reference samples matched so that the meat could be clearly assigned to the cattle killed.
In the Baranya County Zoo in Hungary, 14 wallabies , pampas hares and rare pygmy goats ( Capra hircus nanus ) that were killed by strangulation were apparently victims of dog fighting training . Comparative microscopic examinations of crime scene traces led to suspicion of the zoo's guard dogs. However, the STR analysis of the hair and some traces of blood from the scene of the crime could rule out her as the perpetrator and instead made a single animal of unknown breed responsible for the crime.
DNA analysis has also been used successfully to identify a dog that killed a miniature horse and seriously injured another. The transfer of the perpetrator succeeded with the help of traces of horse blood on the edge of the dog's water bowl. These matched the genetic profile of the killed horse.
A case of doping in horse racing could be cleared up with the help of a found syringe which had apparently been used to administer illegal performance-enhancing substances. DNA analysis of residues on the syringe made it possible to determine not only the identity of the animal concerned, but also the genetic profile of the person who had administered the prohibited substance.
Wildlife Forensics
The wildlife forensics subsection deals primarily with the prosecution, detection and punishment of violations of species and nature conservation (so-called wildlife crimes ). This includes not only the Washington Convention on Species Conservation (CITES), but also national nature conservation laws and local hunting law .
Poaching and illegal animal trafficking are seriously jeopardizing the survival of already endangered species. The reason for the threatened extinction of many species is the profitable trade in their rare and sought-after (luxury) products. Well-known examples are the ivory jewelry , the caviar production and the leather industry. The flourishing market for traditional Asian medicines (e.g. in TCM ) led to a strong demand for urinary bladders , genitals , teeth and horns of certain species ( big cats , rhinos ) - often due to their alleged aphrodisiac effects. Trophy collectors are decimating the last populations of African canids , cats and antelope species . The booming pet market in rich industrial nations has resulted in the unrestrained sell-out of exotic birds, reptiles and fish.
A focus for wildlife forensics is the identification of the species of confiscated animals and their products. In cases where it is no longer possible to distinguish between “protected” and “non-protected” species with the naked eye, the question of whether there has been a violation of species protection must be clarified at the genetic level. This applies e.g. B. for closely related fish species that live in shoals and also tend to hybridize with one another.
Under poaching , the illegal killing and appropriation of wild understood. Here, against an absolute hunting ban for threatened animal species or the general hunting ban z. B. be violated in nature reserves . Failure to comply with a closed season is also included. Breaking gender-specific hunting bans is a common offense: in Florida , wild turkeys are allowed to hunt , but turkey hens are not. The comparatively short hunting season for female deer in Florida (only two days a year) regularly leads to violations of hunting rights. The illegal killing of female animals can be proven through the molecular genetic gender specification based on suspicious venison or traces of blood on hunting clothing and tools.
Numerous cleared up cases of poaching prove the success of the methods used:
- In 2005 hunters who poached a white-tailed deer in a nature reserve in Texas were caught by traces of deer blood on their registered boat. Given the evidence, the accused admitted to poaching but claimed to have killed only one female in the hope of a lesser sentence and in order to keep the antlers . However, the analysis of the DNA was able to refute this statement and clearly determine the sex of the killed piece as male.
- The headless carcass of a mule deer , which was found in New Mexico in 2002 under the remains of a deliberately set forest fire, could be assigned on the basis of DNA to one of three deer head trophies that were later confiscated from a suspect. The reference DNA necessary for the genetic profile was obtained from the spinal cord of the charred carcass.
- In Tanzania in 1998 a suspect who had previously become suspicious was found to have been illegally killing a bushbuck . He was found on the basis of traces of blood and tissue on a hunting knife . His claim to have eviscerated a domestic cattle with the weapon could be refuted by a species identification based on mitochondrial DNA.
- The killing of a hyena species that is under strict nature protection in Zimbabwe in 1998 could be proven to a trophy collector in his home country by comparative skull morphology , although the prepared skull had already been successfully smuggled through customs under a false declaration.
- In India it was possible to prove the killing and consumption of a strictly protected species of peacock . Boiled meat and bird entrails confiscated at the scene of the crime came from only one chicken. But the chopping block that was used to cut meat was able to detect the DNA of a blue peacock using mitochondrial sequence analysis .
Animals as perpetrators
Events in which animals become “perpetrators” primarily include physical attacks against humans and animals, traffic accidents and property damage .
Bite attacks
Bite attacks (e.g. by dogs) often lead to a fatal outcome or cause permanent damage. The victims are mostly small children, old people or other animals. With the help of forensic odontology , statements about the species and race of the attacker can be made on the basis of characteristic bite marks. For this purpose, the width of the dental arch , the depth of the dental impressions as well as species and breed typical tooth anomalies are used.
The attack behavior and the position of the teeth of the domestic dog usually lead to pathognomonic injuries, which consist of a combination of punctiform bites of the canini with multiple, gaping tears ( a-hole-and-a-tear combination ). These are often accompanied by bruises and parallel, crack-like abrasions ( claw marks). The combined impression of both dental arches leads reproducibly to typical round or almond-shaped injuries.
In addition to the conventional processing of a crime scene and the comparison of dental impressions, DNA analysis has become increasingly important for the clarification of such cases. Traces of blood and human hair on the fur, in the mouth or on the collar as well as the stomach contents of the offender are taken into account as well as the examination of hair and traces of saliva of the attacker on the clothing or the body of the victim. Both the STR analysis, and the mtDNA - haplotyping find this successful application. In addition, the use of mitochondrial cytochrome b fragments is suitable for the clear identification of species.
- A woman was attacked and seriously injured by two dogs in a public park in Cook County , Illinois in 2003 . While searching for the dogs, the police found a second victim who died within hours. An aggressive dog was killed and tissue from the second victim was found in its stomach contents. As a result, numerous stray dogs were captured, including the dog that the police believed was the second perpetrator, according to the description of the surviving victim. For public safety it had to be confirmed that the animal was the second attacker. The victims' clothing was checked for canine DNA. In addition to the mitochondrial haplotypes of the dogs belonging to the victims, haplotypes could also be identified that matched those of the two suspect animals.
- In 2000, in Oklahoma, C. Ohman and VA Borja were accused of possessing a vicious dog after their pit bull "Trek" attacked their 74-year-old neighbor, causing permanent disability. The canine DNA isolated from traces of saliva on the victim's clothing matched “Trek” 's genetic profile.
- In March 2000, the body of a seven-year-old boy was discovered on a sports field. As a cause of death dog bites were found. Although the judiciary was hampered by false testimony, a STR analysis of saliva, hair and tiny traces of blood ultimately identified the father's two guard dogs as the perpetrators.
- A young girl was the victim of a severe dog bite attack. However, STR analysis of traces of blood collected from the fur of an eligible dog found no association with the biting. Other forensic evidence such as hair, fiber, and odontological examinations could also not link a specific individual to the case.
- In the case of a nine-year-old boy, one in three Great Danes could be identified as the perpetrator by the saliva on the victim's clothing. This made it possible to dispense with euthanasia of the other two animals in question.
traffic accidents
In order to make the animal owner liable for the damage caused in the event of a traffic accident , it is necessary to clearly identify the causative animal on a DNA basis. Both STR analysis and mitochondrial sequencing can also be used as techniques here.
- A dog was suspected to have caused a traffic accident. Hair fragments from the damaged vehicle were subjected to a sequence analysis of the mitochondrial DNA. The results were compared with reference samples from the accused dog and with four independent control animals. Since the evidence did not match the suspect dog, it could be ruled out as the source of the hair.
Animals as a link
Basics
The central core area of animal forensics are animal tracks, which represent a crucial link between perpetrator and victim in capital crimes . Pets in particular play a role here.
The analysis of animal hair, saliva and various traces of tissue at crime scenes sometimes allows criminologists to use this animal trace material to link a suspect to the crime. The value of the evidence to establish such a link is influenced by the likelihood that
- the assignment of a track to an animal or, conversely, the exclusion of an animal is due to chance,
- the assignment came about due to an error in forensics ,
- there are alternative explanations for the presence of these traces (secondary transfer, contamination , deliberate misleading).
Pet hair
Millions of households have pets such as dogs and cats . Just as ubiquitous as the four-legged friends themselves is their hair, which can be found everywhere in the immediate vicinity of their owners and clings to clothing and objects. Since this hair can be passed on through physical contact ( transfer ), its occurrence can connect a suspect with a victim or a victim such as a perpetrator with a specific crime scene.
Is z. If, for example, a victim is deposited in a vehicle or held in a place to which animals have regular access, this usually results in a transfer of animal hair onto the victim's clothing ("primary transfer"). Animal hair can also be transferred to the victim or to the crime scene if the suspect owns a pet whose hair was still on his clothing during the crime. This is known as "secondary transfer" of trace material. Telltale cat or dog hair is also very common on sticky or clinging surfaces, e.g. B. on paper, adhesive tape, Velcro fasteners and envelopes (ransom or extortion letters).
Hair of animal origin at crime scenes or on the clothes of suspects or victims can also come from a fur coat or animal fur. They are often artificially colored or trimmed and usually no longer have any roots. These traces can - similar to the forensic analysis of fibers - help to convict the perpetrator with the help of circumstantial evidence .
Major criminal cases
The "Snowball" case
This famous criminal case is seen as a precedent for the possibility of associating suspects with capital crimes based on the genetic profile of animal hair.
During the search for the missing Shirley Duguay in 1994 on Prince Edward Island , a bloodstained men's leather jacket was found in a forest. The human blood matched the profile of the missing. However, her suspect ex-husband could not initially be linked to the item of clothing. Some white hairs were discovered in the lining of the jacket, which could be identified as cat hair.
The DNA that was isolated from one of the hair roots served as the basis for genotyping . The resulting genetic profile was compared with a reference profile from the blood of "Snowball", a white cat that lived in the husband's home. There was 100% agreement. The probability of the existence of another cat with the same profile ( probability of match identity ) in Canada or the USA was 1: 6.9 × 10 7 . On the basis of this evidence, the husband was found guilty of murder in 1997 .
The "Chief" case
In Seattle , Washington, a jury convicted Kenneth Leuluaialii and George Tuilefano of particularly serious murder and violation of animal welfare law in connection with Jay Johnson, Raquel Rivera and the mixed breed dog "Chief" who were shot in 1996 . The blood splatters on the pants and jacket of the two suspects, which got on the clothes of the perpetrators through the killing of the dog during the murder of the two victims, were identical to “Chiefs” genetic profile. The probability of error ( p-value ) was 1: 350 million.
The "van Dam" case
One of the most sensational criminal cases based on animal evidence is the murder of seven-year-old Danielle van Dam in San Diego in 2002. The dog hair that was found in the home of suspect David Westerfield could be assigned to the Weimaraner of the van Dams and was found to be main link between Westerfield and the girl's death. For the first time, a murder case was solved here based on the analysis of mitochondrial dog DNA.
Other known cases
- Daniel Schraeder from Vernon, British Columbia , was killed by blunt violence with his small dog. The blood stains on the suspect's pants consisted of a mixture of human and animal blood that could not be examined with the RFLP methods available at the time. In 1996 the case was resumed. The STR typing of non-human blood was able to identify the victim's dog as the source. The Canadian judiciary then brought charges of murder; a year later the suspect was found guilty.
- In 2003, April Misty Morse was kidnapped and murdered in Florida. Her body, handcuffed with tape, was found in a river. Some dog hairs could be secured from the tape. Police suspected that her ex-boyfriend, Brent Huck, murdered her on their boat. The mitochondrial haplotype of the dog's hair was consistent with that of Huck's own dog. He was convicted of kidnapping and murder.
- During a sexual assault in Iowa, the victim watched her dog's urine on the tires of the perpetrator's vehicle. Although the suspect denied ever being anywhere near the house where the victim lived, the dog's genetic profile matched perfectly the detected tracks on the tire.
- Some of the traces of blood found in the alley next to a stabbed London bartender were neither from the victim nor were they of human origin. A University of California institute was commissioned by Scotland Yard to investigate in 2000 . The traces of blood were identified as dog blood and could be assigned to the main suspect's pet.
additional
Food forensics
In the food sector, animal forensics can overlap with the area of food surveillance when violations of the law constitute a significant criminal offense or criminal manipulation is committed on a large scale. In cases where endangered species are used commercially, the transition between food forensics and wildlife forensics is fluid. The sale of incorrectly declared products in violation of the species protection law turns out to be the main problem.
Methods from the field of animal forensics are used here to protect the consumer from deception . A practical example is the detection of incorrectly declared caviar cans in which roe from completely different, protected fish species (e.g. paddle fish ) was processed. It is now also possible to reliably identify eggs illegally sold as freshwater turtle eggs from endangered sea turtles . Molecular genetic tests also allow conclusions to be drawn about the beach on which the eggs were collected, since turtles always return to the place of their own hatching to lay their eggs .
The fraudulent misdeclaration of food ingredients on product labeling is widespread practice, especially in the case of valued, expensive foods. Common criminal offenses to mislead the consumer through false declarations are:
- The sale of products that contain inferior (e.g. offal ) or potentially risky tissue ( mechanically separated meat , confiscated meat , nerve and brain tissue).
- The sale of counterfeit products that consist partly or entirely of undesirable components from foreign animal species (doner kebab, served game).
- Failure to comply with the minimum quantities prescribed in food law with regard to tissue or animal species ( meat and dairy products ).
- The fraud in the declaration of fish with the predicates “caught wild” and “farmed”.
The clear proof that a deception has taken place requires the exact qualitative and quantitative determination of the ingredients . The molecular genetic methods for determining species in foods of animal origin are largely identical to those listed above. Methodological problems cause food that has been heated to a high degree or industrially processed, i. H. Products in which the DNA-containing material is difficult to extract or separate from other substances.
RFLP analyzes of the mitochondrial cytochrome b (see above) allow a distinction between different types of game meat and the differentiation from domestic animals. STR markers are not only used successfully in food forensics to detect the adulteration of food, but also allow a. also the distinction between “wild caught” and “cultivated” in red fish.
Meat law regulations and general public opinion regulate which tissues and organs may not be processed in meat products. These include B. brain and spinal cord, mucous membranes, urinary bladders , and bovine skin .
A classic method of removing foreign tissue - e.g. B. Mechanically separated meat - to be detected in meat products is the histology . All tissue components are identified based on their anatomical-morphological structure and their affinity to certain dyes. The resulting qualitative-morphological findings provide a conclusive statement about the commercial composition of the product.
Classical genetics reaches its limits when it comes to the identification of tissue components in animal products, as different tissues of an individual have completely identical DNA sequences . However, tissues differ in their specific pattern of gene activity : in the muscles completely different genes are active than in the brain . These differences are triggered by subtle chemical changes in certain sections of DNA ( epigenetics ).
From a health perspective ( BSE / Creutzfeldt-Jakob disease ), the detection of bovine brain and nerve tissue in meat products is particularly relevant. Its extraction and processing is prohibited in cattle, sheep and goats. Novel methods such as the combination of real-time PCR with reverse transcriptase PCR not only serve the qualitative detection of proteins typical of nerve tissue , but also enable the extent of contamination with CNS tissue in foods of animal origin.
A case study: species identification from blood
Before the hunt - and working dogs are used to have bloodhounds prove in different tests. One of these is to control their ability to find, pick up and hold onto a trail of wild blood. For this purpose, leaves are prepared with tiny amounts of wild animal blood and distributed as an artificial track in the training area. A trained bloodhound must be able to find and follow the trail without any problems.
In one documented case, all dogs failed such a test. With the help of a molecular genetic determination of species it was possible to prove that the artificial trail was not made from the blood of a wild animal, but consisted of a mixture of sheep and cattle blood.
literature
- K. De Munnynck, W. Van de Voorde: Forensic approach of fatal dog attacks: a case report and literature review. In: International journal of legal medicine. 116, 5, 2002, ISSN 0937-9827 , pp. 295-300.
- P. Savolainen, J. Lundeberg: Dog Genetic Data and Forensic Evidence. In: A. Ruvinsky, J. Sampson (Eds.): The Genetics of the Dog. CABI Publishing, Wallingford et al. 2001, pp. 521-536, ISBN 0-85199-520-9 .
- Egbert Lechtenböhmer: Practical methods for examining hair to determine animal species from a forensic point of view. Hanover 1982 (Hanover, Tierärztl. Hochsch., Diss.).
Web links
- Molecular forensics ("DNA analysis convicts poachers", "caviar trade") at the Leibniz Institute for Zoo and Wildlife Research Berlin
- "Food forensics: tracking down food fraudsters" at ORF
- J. Holmes: Feline Forensics. (Engl.) in Syracuse University Magazine
- " US" Animal Detectives "Fight Crime in Forensics Lab " at National Geographic
- Dunn, T .: " Caught, After the Act: How Crime Solvers Use Scientific Sleuthing to Stay Hot on the Trail of Wildlife Criminals " in ZoeGoer 6/2003 ( Smithsonian National Zoological Park )
swell
- ^ AJ Jeffreys, DB Morton: DNA fingerprints of dogs and cats. In: Animal Genetics 1987 (18): 1-15
- ^ DB Morton, RE Yaxley, I. Patel, AJ Jeffreys, SJ Howes, PG Debenham: Use of DNA fingerprint analysis in the identification of the sire. In: Veterinary Record 1987 (121): 592-4
- ^ Brandt G. Cassidy, Robert A. Gonzales: DNA testing in animal forensics . In: Journal of Wildlife Management . tape 69 , no. 4 , 2005, p. 1454-1462 , doi : 10.2193 / 0022-541X (2005) 69 [1454: DTIAF] 2.0.CO; 2 .
- ^ I. Pfeiffer, B. Brenig: X- and Y-chromosome specific variants of the amelogenin gene allow sex determination in sheep (Ovis arie) and European red deer (Cervus elaphus). In: BMC Genet 2005 Mar 16; 6 (1): 16
- Jump up ↑ C. Eichmann, B. Berger, M. Reinhold, M. Lutz, W. Parson: Canine-specific STR typing of saliva traces on dog bite wounds . In: Int J Legal Med 2004 Dec 118 (6): 337-342
- ^ P. Wiegand, V. Schmidt, M. Kleiber: German shepherd dog is suspected of sexually abusing a child. In: Int J Legal Med 1999; 112 (5): 324-5
- ↑ For a specific case cf. D. Beamonte, A. Guerra, B. Ruiz, J. Alemany: Microsatellite DNA polymorphism analysis in a case of an illegal cattle purchase. In: J Forensic Sci 1995 Jul; 40 (4): 692-4
- ^ G. Giovambattista, MV Ripoli, JP Liron, EE Villegas Castagnasso, P. Peral-Garcia, MM Lojo: DNA typing in a cattle stealing case. In: J Forensic Sci 2001 Nov; 46 (6): 1486-6
- ↑ Z. Padar, M. Angyal, B. Egyed, S. Furedi, J. Woller, L. Zoldag, S. Fekete: Canine microsatellite polymorphisms as the resolution of an illegal animal death case in a Hungarian zoological garden. In: Int J Legal Med 2001 (115): 79-81
- ^ A b c d A. Agronis: The Blood Wasn't Human. UC Davis brings high-tech crime investigation to the animal world. ( Memento of the original from November 24, 2005 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ dnadiagnostics.com ( Memento of the original from May 7, 2006 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ a b www.napa.ufl.edu ( Memento of the original from September 1, 2006 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ See www.tpwd.state.tx.us
- ↑ a b nationalzoo.si.edu ( Memento of the original from January 17, 2006 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ See www.izw-berlin.de
- ^ SK Gupta, SK Verma, L. Singh: Molecular insight into a wildlife crime: The case of a peafowl slaughter. In: Forensic Sci Int 2005 Nov 25; 154 (2-3): 214-7
- ^ W. Parson, K. Pegoraro, H. Niederstatter, M. Foger, M. Steinlechner: Species identification by means of a cytochrome b gene. In: Int J Legal Med 2000; 114 (1-2): 23-8
- ↑ Dog Attacks in Cook County ( Memento of the original from May 20, 2006 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. 2003
- ↑ a b A. Day: Nonhuman DNA Testing Increases DNA's Power to Identify and Convict Criminals. ( Memento of the original from December 20, 2004 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. In: Silent Witness 2001 6 (1)
- ↑ Z. Padar, B. Egyed, K. Kontadakis, S. Furedi, J. Woller, L. Zoldag, S. Fekete: Canine STR analyzes in forensic practice. Observation of a possible mutation in a dog hair. In: Int J Legal Med 2002 (116): 286-8
- ^ P. Brauner, A. Reschef, A. Gorski: DNA profiling of trace evidence - mitigating evidence in a dog biting case. In: J Forensic Sci 2001 Sep; 46 (5): 1232-4
- ^ PM Schneider, Y. Seo, C. Rittner: Forensic mtDNA hair analysis excludes a dog from having caused a traffic accident. In: Int J Legal Med 1999; 112 (5): 315-6
- ^ MA Menotti-Raymond, VA David, SJ O'Brian: Pet cat hair implicates murder suspect. In: Nature 1997 (386): 774.
- ↑ Judge sentences van Dam killer to death. CNN on March 7, 2003
- ↑ Royal Canadian Mounted Police Detachment File Number 91-0693 ( Memento of the original from May 20, 2006 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (reference: Schraeder, Daniel Fred-Murder of), 1996-1997
- ^ State of Florida v. Brent Robert Huck ( Memento of the original from May 20, 2006 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 2003
- ^ MA Renshaw, E. Saillant, RE Broughton, JR Gold: Application of hypervariable genetic markers to forensic identification of 'wild' from hatchery-raised red drum, Sciaenops ocellatus. In: Forensic Sci Int 2006 Jan 6; 156 (1): 9-15
- ↑ Provision of a reverse transcriptase (RT) real time PCR using acidic glial fiber protein (GFAP) messenger (m) RNA as a genetic marker for the organ or species-specific detection of CNS tissue of the animal species "cattle", " Sheep "and" Pig " ( Memento of the original from May 24, 2005 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ I. Pfeiffer, J. Burger, B. Brenig: Diagnostic polymorphisms in the mitochondrial cytochrome b gene allow discrimination between cattle, sheep, goat, roe buck, and deer by PCR-RFLP. In: BMC Genet 2004 Oct 5; 5:30
