Forensic Biology - Term Paper Example

Forensic Biology Introduction Forensic biology is the scientific application of biological techniques to law enforcement practices. It, in particular, includes various sub-disciplines of forensic botany, forensic anthropology, forensic entomology, and DNA based technologies (Roxie C. L., 2003). As a biological concept, forensic biology is a technique that has been applied to prove a suspect’s presence at a crime scene, identify illegal products from endangered species, effectively solve crimes by means of matching crimes scene evidence to suspects, promptly investigate airplane bird strikes, and also to investigate bird collisions with wind turbines of airplanes. 1. Forensic anthropology This is the identification and recovery of remains as applied in extreme situations where conventional techniques are proved to be unable to effectively and correctly determine the precise identity of the remains. It applies science of physical anthropology and human osteologies within legal settings, i.e. in criminal cases where the victim’s remains are in the advanced stages of decomposition. Anthropologists, who study forensic anthropology, are able to concisely figure out some features based on the skeletal remains. For instance race, age, sex and statures can in most instances be determined by both taking account of the remains and analyzing the structural clues in the bones that are decomposed, burned, mutilated and are unrecognizable. Further still, it can help in determining if an individual under investigation was affected by accidental or violent trauma/ disease before or at the time of his/ her death (Skinner M., 2010). Illustration 1: It shows how to measure the limps This study (Forensic Anthropology) uses scientific approaches in the determination and identification of an individual’s identity, duration sine death, the causes of death, and the manner in which the death incidence occurred. All these procedures are carried out in accordance to well spelt codes of ethics provided by the American Anthropological Association (AAA) in the Ethical Code of AAA. i. Bones present In the case where the identified bone represents a human bone, an investigator has to identify the bone elements present/ absent. In the first instances, anthropologists begin the processes by organizing the recovered bones on a table as they would be in a living person – anatomical position. This is mainly for the purposes of creating an informal visual inventory to allow for any missing element to be quickly identified; assisting the analyst to work systematically through the entire skeleton by performing a detailed inventory and examining each bone for trauma, pathology, and any life history traits; and consideration of the skeleton as either whole or look for any visible inconsistencies among the present elements after the intensive process of examining each bone. Skeletal inventories at the recovery site are very crucial in allowing searchers and scene respondents to determine what they might be seeking and has not been discovered yet, hence enabling for a full recovery. Under anthropology, inventories are considered important from a criminal point of view for coming up with the elements that are and that are not, perpetrator behavior and taphonomy. ii. Determination of whether the remains are modern or ancient Anthropologists often tell the difference between an ancient and a modern skeleton by their context of decomposition; which includes the location, position, and condition of the recovered body, and provide clues to the events that led to its consequential burial. Further, the associated material evidence that can be used to suggest the precise origin of recovered set of bone remains. iii. Sex Sex of an individual is defined as biological aspects that is determined by genes, and are expressed mainly through the reproductive organs and hormones; and also through musculature, body hair, and sexual characteristics. The visual and hormonal variations enabling for the distinctions between living males and females together create physiological differences in their respective skeletons, which is most obvious in the pelvic bones and the skulls. The variations in the pelvis are due to the evolutionary and functional constraints and the fact that females are adapted to give birth to big-headed babies, hence leading to the structural differences between the males and females. On the other hand, males are known to have larger skulls as compared to those of the females; in addition to greater muscle developments and adversely rugged muscle parts. Besides the use of skulls and pelvis in determining remain’ sex, accurate measurements of other human bones by considering the expected overlap between the males’ and females’ bones are fundamental. iv. Age Age estimation depends on growth and decline of an individual after his or her death. Any growth and development changes to a greater extent lies upon the degree and identified location of growth within the bone and dental formation/ eruption from the gums in immature people. v. Ancestry Anthropologists do analyze the skeletal characteristics, in trying to assess ancestry, which are common in some populations as compared to others. This classification can place an individual into African, Asian or European categories. vi. Stature The process of estimating living stature is fundamental in the identification of any unknown individual. Anthropologists are able to take account of the arm and leg bones and calculate using the Mathematical formulae of sex and ancestry classification due to the close relations between limb lengths and heights. 2. Forensic botany Forensic botany can be described as the application of plant Sciences to related criminal investigations in the courts of law, through incorporating palynology which if the study of pollens; dendrochronology which is the study of tree rings, limnology which is the scientific study of aquatic environments, systematic which is the scientific classification of plants; ecology which is the scientific study of ecosystems and finally molecular biology. Illustration 2: It shows how to collect flowers containing pollens for the purposes of laboratory identification. Forensic botany primary works by providing any necessary connections that exist between evidence and a crime in a court of law’s investigation. A good example is the use of pollen to connect a suspect to a victim or scene. According to the Science of plants, pollen can be classified as a power-like substance that is continuously released by plants during their reproductive cycle, and transported by wind. This transportation mechanism enables the pollen grains to be found on people’s clothes, hair and even skin. In the instance of discovery of a rare plant type near a murder victim by the investigators, presence of its pollen on any suspect is likely to place them at the incidence scene. In addition for the common plants, each and every environment is known to have its own unique combination of pollens, hence signifying the link between the identified suspect and the location/ scene. Under such conditions still, pollen signs can be used to indicate that a body has been trans-located or give a suggestion of the type of area of the original crime. i. Botanical evidence and clandestine graves In some instances, botanical evidence can be used to identify clandestine graves. For situations where soil is disturbed for any reasons, some plants immediately take position of the fresh surface. However, other types of plant species follow in succession until the disturbed area completely recovers; although composition and distribution of the new assemblage may never be exactly similar to the original community of plants. Presence of any buried body in a given region has the effect of chemically altering the soil and either facilitation or obstructing rapid growth of plants. Looking at it from both aspects, the resulting disturbed area will be at a different stage of growth as compared to the surroundings. ii. Botanical evidence and estimation of time elapsed since the time of death The aquatic species of plants can also be quite helpful in this situation of criminal investigations. Algae and diatoms, for instance, can be effectively used in the diagnoses of death cases which have resulted from drowning in the freshwater grounds. Specialized botanists are able to uniquely identify the number and species of diatoms that are in the lungs and other identified tissues and scientifically correlate them with the flora existing in the location the body was discovered. Since diatoms and algae in the fresh water vary periodically/ seasonally, their variety and abundance within an area can be appropriately used to tell time since death or to generate a signature indicating the aquatic habitat as can be matched to a body in a given location. Besides, trees and their roots are very instrumental in determining elapsed time since the time of death, duration since a body was at an identified location or the period during which the death incident occurred. Since woody plants and trees grow in annual cycles with variations on the environmental conditions, their growth rings can be effectively counted to give the timing of an event. For our case analysis, this effect is particularly accurate incase plant roots grow through clothing or bone of the dead body. Partial damage to the root growth can equally be used to suggest an accurate since the interruption identified occurred. iii. Limitations The common nature of pollen can make it very difficult to effectively associate particular pollens with some specific area in trying to determine scenes or witnesses. Case investigators have to ensure that the buried evidence is not contaminated by the fresh pollen at the scene, otherwise fault interpretation and information will be collected. In the case of unprotected evidence, determination of whether the pollen existed at the time of death or not becomes very difficult and almost impossible. High precautions are also needed while dealing with root evidence. Instances of false, over, or distortion of rings can lead to over or under estimation of the actual length of time an identified body has been at the scene by the investigators. When a body is covered the original vegetation in the area at the time of the burial, no difference will be on the vegetation on the ground as it would pretty much look like the plants have been at the scene the body which is buried underneath. Situations have also been evidenced where the decomposition process of the body is resulting into the delaying of the growth of plants around it and causing the plants younger than the actual burial time of the body. After data collection, processing and documentation, the information must be preserved well to make the available evidence easy for interpretations, valid and admissible in courts of law. 3. Forensic entomology This is the technique of studying insects for the purposes of medico-legal reasons. With regards to court of law cases, insects can be used in a number of ways to facilitate reaching a solution to a crime case by precisely estimating the average time since the time of death. Illustration 3: this is a picture showing how forensic entomologists do collect insect evidence from the grave. Individuals’ bodies begin to decompose as soon as they are dead, with the action of microorganisms i.e. bacteria and a series of arthropods. The rate of decomposition of a body entirely depends on the climatic conditions of where the body is. For instance, the decomposition rate determiners can be the weather conditions, insects/ any similar substance present in the body to facilitate or inhibit faster decomposition, the individual’s body size/ weight, the clothing type, and whether the body is buried or exposed to decomposing elements. The fact that a dead body undergoes a constant series of changes gives room for necessary investigation and conclusion on the estimate period that an individual has been dead. These stages are fresh, putrefaction, fermentation, dry decay and the process of turning the body into a skeleton; which are associated with different types of organisms feeding off the body and recycling the matter. Investigators therefore come in to collect and study the insects that are feeding on the body at a particular time to help determine time elapsed since the individual died. In the estimation of time since death, two criteria are used: i. The use of succession waves of insects. This strategy is applied in the case where a person has been dead for duration of a month or so. It is based on the fat that human body facilitates a rapidly changing ecosystem during the process of its decomposition. The remains, herein, goes through some physical, biological and chemical alterations and at different stages which attracts different species of insects. Forensic entomologists are capable of telling a time period in which death occurred by determining the regional insect fauna and durations of colonization. A good case summation of this is that Calliphoridae and Sarcophagidae (types of flies) do arrive within a time lapse of just a day of death in case the condition is conducive for them or rather within just a few minutes when blood and other body fluids are still present on the body. Contrary, Piophilidae do arrive at the scene at a later stage since they are only interested on the body at later stages of decomposition. Other insects are never interested on the dead body but usually waits for the insects feeding on that body complete their lifecycle, die and they come to feed on them (dead insects). ii. The maggot age and development used in the cases of shorter durations of a month or less, before the discovery. Besides the descriptions and explanations given above, the Science of forensic entomology can as well be used for other analysis. For instance: Any detection of unfamiliar insects on the body that are not found within the surround of the body pretty much suggests that the body was moved from another environment, hence helping to locate the right place where death might have occurred. In case of evidences that the insect cycles are disrupted, remarks could be made that the killer (s) had actually returned to the scene at which crime occurred. Therefore, entomologists are able to determine an estimation of the date death took place and the possible date the killer (s) returned to the scene. In situations where the maggot activities are determined to have taken place away from the natural openings on the body, possible wounds on the body would be the conclusion. Despite the numerous advantages of this process, its limitations have also been established and their possible effects on the outcome of such analysis. Among them include the facts that immediate results are in most case impossible to obtain since adequate time is needed to rear insects for studies; treatments of the body before burial also affects time estimation since they affect natural decomposition of the bodies; and the dependency of the time of death on the precise temperature readings from the crime scene. 4. DNA based techniques Deoxyribonucleic Acid (DNA) is classified as a molecule which consists of the generic code for every organism, helping to store any essential instructions for constructing the cells and regulating their possible functions. Illustration 4: it shows a forensic DNA analyst who is placing a bone lyses solution into a centrifuge. Every person has his/ her own unique DNA sequence, hence helping in the differentiations. In an attempt of identification of an individual, the forensic investigators have to come up with a genetic profile (which is a set of various numerical values, exclusive to the person under investigation). The DNA is first extracted from the sample, real-time polymerase chain reaction is then carried out so as to detect and also to quantify the amount of DNA collected, then amplification of the results, and lastly gel electrophoresis. In all these processes, the most crucial component of the DNA analysis is the investigation of the Short Tandem Repeats (STR) which is always very distinct from one individual to another since its different genes are inherited from each of the parents of every individual (Bieber, Frederick et al., 2006). Hence, it is true that DNA analysis of STR can be used in the identification process. In addition, sex identification is another section in the generation of the DNA profile. Forensic analysis focuses on SRY gene, amelogenin gene and repetitive sequences which are based on the Y-chromosome. Through these processes, sex of an individual is determined from nDNA studies basing on the facts that males have one Y and one X chromosome while female have two chromosomes. i. The presence of SRY genes in the sample collected from an individual is an indication that the individual is a male; otherwise its absence is a sign of one being a female since these genes are responsible for the development of a fetus into a male. ii. The second study, which is of amelogenin, is aimed at a gene that is mainly found on the X and Y-chromosomes. Differences used are that the gene sequence is relatively longer in males as compared to that in females. On the visualization of these differences in length, the analyst will be able to determine the sex of that very individual. iii. The third situation is of Y-STR technique which is aimed at the DNA on the nuclear genome. It seeks for the short repeats of the Y-chromosomes which are indeed only present in the male individuals. This technique can sequentially be applied in the test for paternal relationships because of the scientific fact that males do inherit their Y-chromosomes from their fathers (Bieber, Frederick et al., 2006). Another system can be the study of the mitochondrial DNA, though for the exploration of the family relationships and tracings along the female lines since it passes exclusively from a mother to a child. Reference Bieber, Frederick et al., (2006). “Finding Criminals Through DNA of Their Relatives” Science. 312 Sci. 1315, 1315–16. Ethical Code of the AAA Skinner M. (2010). “Taking the Pulse of Forensic Anthropology in Canada.” Canadian Society of Forensic Science; pp 191–203. Roxie C. L. (2003). Pioneer in Forensic Ornithology Aided Aviation. Los Angeles Times: in print edition B-9, August 18, 2003. Read More