Forensic biology

Forensic biology is the application of biology to associate a person(s), whether suspect or victim, to a location, an item (or collection of items), another person (victim or suspect, respectively)[1]. It can be utilized to further investigations for both criminal and civil case. Two of the most important factors to be constantly considered throughout the collection, processing, and analysis of evidence, are the maintenance of chain of custody as well as contamination prevention, especially considering the nature of the majority of biological evidence[2]. Forensic biology is incorporated into and is a significant aspect of numerous forensic disciplines, some of which include forensic anthropology, forensic entomology, forensic odontology, forensic pathology, forensic toxicology. When the phrase "forensic biology" is utilized, it is often regarded as synonymous with DNA analysis of biological evidence.

Disciplines

DNA Analysis

DNA, or deoxyribonucleic acid, is one of the most popular pieces of evidence to recover at a crime scene[2]. More often than not, evidence containing DNA is regarded to as biological evidence. With all of the substantial advances that have been made regarding DNA, biological evidence is recognized to be the golden standard in forensic science.

At the scene, biological evidence must be initially visibly recognized. Sometimes this is not always possible and the aid of an alternative light source, or ALS, is required. Once identified as a potential source, presumptive tests are conducted to establish the possibility of the specified biological presence (semen, saliva, blood, urine, etc.)[2]. If positive, samples are collected and submitted for analysis in the laboratory, where confirmatory tests and further tests are performed [1][2].

DNA analysis has numerous applications such as paternity testing, identifications of unknown human remains, cold case breakthroughs, as well as connecting suspects and/or victims to a piece(s) of evidence, a scene, or to another person (victim or suspect, respectively)[2]. Nuclear DNA evidence can be recovered from blood, semen, saliva, epithelial cells and hair (if the root is still intact)[2] . Furthermore, Mitochondrial DNA can be recovered from the shaft of hair, bone and the roots of teeth. When there is a known sample available to compare to unknown samples, 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 a known sample[1]. In order to utilize CODIS, STR analysis must be performed on the sample[3]. If there are no known samples available, the nuclear profile can be entered into the Combined DNA Index System, or CODIS, to find a possible match or hit.

Forensic Anthropology

Anthropology is applied to forensics most regularly through the collection and analysis of human skeletal remains[1]. The primary goals of anthropological involvement include identification and aiding in scene reconstruction by determining details regarding the circumstances of the victim's death. In cases where conventional techniques are unable to determine the identity of the remains due to the lack of soft tissue, anthropologists are required to deduce certain characteristics based on the skeletal remains. Race, sex, age and possible ailments can often be determined through bone measurements and looking for clues throughout the skeletal structure.

Forensic Odontology

Odontologists or dentists can be used in order to aid in an identification of degraded remains. Remains that have been buried for a long period or which have undergone fire damage often contain few clues to the identity of the individual. Tooth enamel, as the hardest substance in the human body, often endures and as such odontologists can in some circumstances compare recovered remains to dental records.

Forensic Pathology

A forensic pathologist is a medical doctor who is an expert in both trauma and disease and is responsible for performing autopsies. He/she applies their extensive knowledge of the human body and possible internal and external inflictions as he/she performs an autopsy, to hopefully ascertain the manner and cause of death [1]. Information derived from the autopsy often greatly assists investigative efforts as well as scene reconstruction.

Forensic Toxicology

Forensic toxicology is the use of toxicology and other disciplines such as analytical chemistry, pharmacology and clinical chemistry to aid medical or legal investigation of death, poisoning, and drug use. The primary concern for forensic toxicology is not the legal outcome of the toxicological investigation or the technology utilized, but rather the obtainment and interpretation of results.

Current Issues

Sexual Assault Kit Backlog

Prior to DNA testing, many sexual assault cases could only rely on "his said, she said" and possible witnesses. Even once DNA analysis was available, many sexual assault kits, or SAKs, were never tested and thrown into a backroom or storage facility, only to be forgotten about until discovered. Now that DNA analysis is frequently utilized in the majority of cases, most SAKs are examined and analyzed. However, the issue remains about the preexisting SAKs that have never been tested. A prevalent issue then, that still extends to now, is the absence of funds to actually process and analyze these SAKs. Many districts would dedicate their funds to homicides or more high profile cases and sexual assaults would be swept to the side. The biggest concern about all of these SAKs, is how to go about processing all of them, especially as more and more are being found each year[4].

Cold Cases

With the considerable amount of advancements in DNA analysis, old, open cases that still have intact evidence can be examined for biological evidence[3]. New profiles are uploaded to CODIS everyday so the base population to search and compare to increases. Biological testing for cold cases, specifically homicides, encounter similar roadblocks as the SAKs - lack of funds or the DNA samples have not been properly stored thus too much degradation has occurred for viable analyses.

In popular culture, forensic biology is frequently portrayed in shows like Law & Order, Bones, CSI, Dexter and Castle. However thanks to Hollywood's depiction of forensic science, the analysis of biological evidence has fallen prey to the CSI Effect, which results in the public's perception of its capabilities being severely distorted and its limits blurred.

See also

References

  1. 1 2 3 4 5 Houck, Max; Siegal, Jay (2006). Fundamentals of Forensic Science. China: Academic Press. ISBN 978-0-12-356762-8.
  2. 1 2 3 4 5 6 Fisher, Barry A. J.; Fisher, David R. (2012). Techniques of Crime Scene Investigation. Boca Raton, Florida: CRC Press. ISBN 978-1-4398-1005-7.
  3. 1 2 National Institute of Justice, Office of Justice Programs (July 2002). Using DNA to Solve Cold Cases.
  4. ↑ National Institute of Justice (March 2016). "Creating a Plan to Test a Large Number of Sexual Assault Kits" (PDF).
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