Forensic DNA Testing Essay Example | Topics and Well Written Essays - 1250 words

Forensic DNA Testing - Essay Example The DNA Identification Act of 1994 formalized the FBI's authority to establish a National DNA Index System (NDIS). The CODIS is different from the NDIS in that NDIS is the national database whereas CODIS is used today by more than 40 law enforcement laboratories in over 25 countries.( FBI, 2009) The CODIS system requires > 4 RFLP markers and/or 13 core STR markers. Now, what are STR's Most of the DNA is identical to the DNA of others in the human genome. However, there are inherited regions of our DNA that may not necessarily code for proteins termed as introns, which can vary from person to person. A variation in the DNA sequence between individuals is termed as "polymorphism". Sequences which display the highest degree of polymorphism are very useful for DNA analysis in forensics cases and paternity testing. Forensic DNA testing is based on analyzing the inheritance of a class of DNA polymorphisms known as "Short Tandem Repeats "or STRs. STRs are short sequences of DNA, normally of length 2-5 base pairs, that are repeated numerous times in a head-tail manner, for example the sequence GATA occurs anywhere between 5-16 repeats at the locus D7S820. The number of repeats within an STR is referred to as an allele. Thus there are 12 different alleles possible for the D7S820 STR. Because there 12 different alleles for this STR, there are therefore 78 different possibl e genotypes, or pairs of alleles. Specifically, there are 12 homozygote's, in which the same allele is received from each parent, as well as 66 heterozygote's, in which the two alleles are different. Norrgard,K.(2008) After an extensive validation study, 13 STR loci were selected to form the core (i.e., required) genetic markers for CODIS. The methodology involved in the STR analysis is as follows. The DNA is isolated from the sample. The STR region in the DNA is amplified using PCR and suitable primers. The various companies manufacturing STR kits typically vary in the primer they employ. PCR enables even nanogram amounts of sample to be sufficient for evaluation. Only when all the 13 markers match in the source and the felon sample is the convict included in the source of crime. Even after all the 13STR's are matched a statistical test is carried out to analyze the overall STR frequency. It is assumed that the STR's follow law of independent assortment which implies that each member of a pair of homologous chromosomes separates independently of the members of other pairs so the result is random and that the population mates randomly by the FBI in analyzing the STR profiles. The Hardy Weinberg l aw was used to calculate gene frequency which states that the gene frequencies remain conserved from generation to generation. It is important to understand that this number is the probability of seeing this DNA profile if the crime scene evidence did not come from the suspect but from some other person. If all the STR's from the sample are not retrievable due to damaged or an extremely old source of DNA, then the STR profiling cannot be used as the sole evidence and other proof's have to be collected. Though the STR profiling is rapid the CODIS database is currently facing a backlog of >600,000 samples to be keyed in.In addition to

Importance of Practical Experience in Clinical Nursing Essay

Importance of Practical Experience in Clinical Nursing - Essay Example A lot of challenges face nurses in the field today as regards the extraction of information from the patients. As Kurtz, Silverman, & Draper, (2005) mentions, closely intertwined and vivid explanations of the undertakings need to be clearly outlined in order to deduce the correct mechanisms for arresting the situation. Failure to achieve this often leads to misappropriation of the necessary measures and steps for various problems (Seidal, Ball, Dains, & Benedict, 2010). This paper as a reflection on my personal experience as a practicing nurse in the medical field, it addresses my encounter with a patient I attended to who had an eye injury following blunt trauma and was quite distressed as he was in pain and unable to see out of the eye initially. As a practicing nurse, this was the most trying moment of my life. I confess having not experienced such incidences before and dealing with the condition above was a great challenge yet a greater opportunity to learn much on how to deal with various traumatizing medical issues that I am yet to face in the course of my practice. I had been taught of the various instances of trauma in various categories of patients but did not get a practical system to strengthen and seal fast the theoretical applications. Having met the patient was the most fulfilling part of my life that I cannot easily forget. I was terrified at the sight of the patient upon his reception and especially when I was included in the team of nurses who were to attend to him. Trauma according to medical research is one of the most endearing factors in human life. Several outcomes are expected in different patients depending on the various ways in which the patient or persons close to the patient help him or her in managi ng the trauma (Springhouse, 2008). Having acquired serious musculoskeletal injuries, the patient had experienced serious infection on his left eye leading to its immediate loss.