Forensic biology is the application of biology to law enforcement. It includes the subdisciplines of Forensic anthropology, Forensic botany, Forensic entomology, Forensic odontology and various DNA or protein based techniques.
Applications Forensic biology has been used to prove a suspect was at a crime scene, identify illegal products from endangered species solve crimes by matching crime scene evidence to suspects, investigate airplane bird strikes, and investigate bird collisions with wind turbines.Evidence transfer and collection. Biological specimens can be used to make linkages (for example, person-person, person-other physical evidence, and person-crime scene). In general, biological evidence can be transferred by direct deposit or by secondary transfer.
Blood, semen, body tissue, bone, hair, urine, and saliva can be transferred to an individual’s body or clothing, to an object, or to a crime scene by direct deposit. Once liquid biological materials are deposited, they adhere to the surface or the substratum and become stains.Nonfluid biological evidence, such as tissue or hair, can also be transferred by direct contact. Blood, semen, tissue, hair, saliva, or urine also can be transferred to a person, object, or location through an intermediary (a person or an object).
With secondary transfer, there is no direct contact between the original source (donor of the biological evidence) and the target surface. Secondary transfer may, but does not necessarily, establish a direct link between an individual and a crime. The ability to analyze biological evidence is impacted by many factors regarding its collection.Unless the evidence is properly recognized, documented, collected, packaged, and preserved, it will not meet the legal or scientific requirements for admissibility into a court of law.
Laboratory analysis The identification of individuals by analyzing their biological material such as blood, semen, hair, and bone has been used since 1904. Historically, testing has been based on serological markers, including red blood cell antigen systems, isoenzymes, red cell and serum protein variants, and human leukocyte antigens (HLAs).Since the mid-1980s, DNA analysis has been increasingly important in forensic science, forensic medicine, and paternity testing. Genetic variation can be detected by many DNA tests, including restriction fragment length polymorphism (RFLP) analysis, polymerase chain reaction (PCR), and DNA sequencing.
Developments in the 1990s, such as more sensitive and discriminating PCR typing methods, the felon DNA databank, and increased governmental funding, have greatly enhanced the use of DNA in criminal investigations.Serological methods. Prior to the advent of DNA typing, serological tests were employed to identify the source of the biological evidence, to determine if the sample was of human origin, and to individualize the specimen. Today, serological analysis is generally limited to identifying the type of biological evidence collected.
Subsequently, the evidence is individualized by DNA analysis. The process of examining items for the presence of biological material begins with recognizing and identifying likely candidates for further testing. First, various screening tests determine if a stain could be blood, saliva, or semen.Second, confirmatory tests identify the source of the body fluid (for example, human blood).
Third, the body fluid is individualized. Felon DNA databanks A significant development in forensic science is felon DNA databanks. Given the high rate of recidivism associated with sexual assault, felon DNA databanks are particularly useful for solving these crimes; they will also assist in the investigation of many other violent crimes. The national DNA databank system, CODIS (Combined DNA Index System), became operational in fall 1998.
This allows states to compare their no-suspect profiles to a national DNA repository and solve additional crimes. Disciplines Forensic anthropology is the application of the science of physical anthropology and human osteology (the study of the human skeleton) in a legal setting, most often in criminal cases where the victim’s remains are in the advanced stages of decomposition. A forensic anthropologist can also assist in the identification of deceased individuals whose remains are decomposed, burned, mutilated or otherwise unrecognizable.The adjective “Forensic” refers to the application of this subfield of science to a court of law.
Forensic entomology is the application and study of insect and other arthropod biology to criminal matters. Forensic entomology is primarily associated with death investigations; however, it may also be used to detect drugs and poisons, determine the location of an incident, and find the presence and time of the infliction of wounds. Forensic entomology can be divided into three subfields: urban, stored-product and medico-legal/medico-criminal entomology.Forensic ornithology Bird remains can be identified, first and foremost from feathers (which are distinctive to a particular species at both macroscopic and microscopic levels), and also DNA.
Forensic dentistry or forensic odontology is the proper handling, examination and evaluation of dental evidence which will be then presented in the interest of justice. The evidence that may be derived from teeth, is the age (in children) and identification of the person to whom the teeth belong. This is done using dental records including radiographs, ante-mortem (prior to death) and post-mortem photographs and DNA.Forensic odontology is derived from Latin, meaning forum or where legal matters are discussed.
The first forensic dentist in the United States was Paul Revere, who was known for the identification of fallen revolutionary soldiers. The other type of evidence is that of bite marks, left on either the victim (by the attacker), the perpetrator (from the victim of an attack), or on an object found at the crime scene. Bite marks are often found on children who are abused. Forensic dentists are responsible for six main areas of practice:•Identification of found human remains •Identification in mass fatalities Assessment of bite mark injuries •Assessment of cases of abuse (child, spousal, elder) •Civil cases involving malpractice •Age estimation Forensic botany is the study of plants, and plant matter, as they pertain to criminal death investigation.
Very often, trace botanical evidence can link an object or suspect to the scene of a crime, as well as rule out a suspect or support an alibi. A plant’s anatomy and its ecological requirements are in some cases species-specific; correct interpretation of botanical evidence can give vital information about a crime scene or the whereabouts of a suspect or victim.The use of botanical evidence in legal investigations is relatively recent. Today, forensic botany encompasses numerous subdisciplines of plant science: palynology, anatomy and dendrochronology, limnology, systematics, ecology, and molecular biology.
DNA based techniques DNA based evidence is perhaps one of the strongest linking tools that law enforcement investigators have at their disposal. DNA evidence can definitively link a suspect to either a crime scene or victim. Nuclear DNA evidence has been recovered from blood, semen, saliva, skin cells and hair.Furthermore Mitochondrial DNA can be recovered from both bone and teeth dating back thousands of years.
Laboratory analysis of DNA evidence generally involves the sample being amplified and quantified by a form of the Polymerase chain reaction known as Quantitative PCR or qPCR. (PCR) amplification of any sample recovered followed by sequencing via Capillary electrophoresis in order to obtain a DNA profile which can be compared to suspect DNA. DNA can also be extracted from animals and used to at least identify the species, for example bird or bat remains on an airplane or wind turbine.
