APPLICATIONS OF DNA FORENSICS IN

TODAY’S WORLD Applications of DNA Forensics

By: Patricia Beauzile, Meghan moore, Donald Hahn, Emily Hollens, Darwin Omar Larco As the field of DNA forensics is ever increasing, the uses
History of DNA forensics are also increasing, and the current
Forensic science is a developing field that owes its techniques are being refined.
progression to the technical advancements made in the lab. Some of the most common and important uses of
This field was first coined as a science in 1936, but only DNA forensics are:
recently has the area been recognized as an important asset Diagnosis of/ Development of cures for Inherited
in the fight against crime. This is due in large part to DNA Diseases
fingerprinting. DNA fingerprinting was discovered Special Cases ~ diagnosis of cystic fibrosis, hemophilia, Huntington's
accidentally by Alec Jeffreys in 1984 and published in disease, familial Alzheimer's, sickle cell anemia,
Nature in 1985. This discovery revolutionized the area of DNA forensic science has recently been made popular because of its use in a number of high profile cases.
In 1991, scientists exhumed the mass grave of the historical ruling Romanov family. The last generation of the ruling Romanov family, as well as their servants, thalassemia, and many others
molecular biology and became a gateway for many key ~ education of prospective parents as to the risks of
developments in forensics, which let to the formation of were captured, murdered, and buried in a mass grave in Siberia in 1918. After the break up of the Soviet Union, scientists used DNA forensic evidence to identify the
bodies in the mass grave. The forensics team collected DNA from dental remains, and skeletons. As a result, they discovered that of the 11 people who were reportedly having an affected child
DNA databases that store the DNA information of ~ identification of DNA patterns associated with diseases
suspected criminals or already convicted criminals. The executed and buried; only nine were found in the grave.
In 1994, DNA forensic evidence was collected in form of blood, skin, and semen samples taken from the scene of the crime and was analyzed and compared to to help establish treatment
largest of such databases, UK’s National DNA Database, Biological Evidence
reported in 2004 that it contained 2,400,000 individual O.J. Simpson’s DNA taken from a cheek swab sample. Although the blood sample and the swab sample matched, this evidence was not used in court due to it nature. In
this case, forensic evidence was considered circumstantial, and did not prove absolute guilt. ~ paternity/maternity testing
samples. In the United States there are similar databases, ~ linkage of suspects to crime scenes
such as the National DNA Indexing System and Combined In the 1998 Swissair Flight 111 disaster, short tandem repeat (STR) DNA was used to compare the DNA samples from the disaster sight with the DNA samples
from searching family members. Scientists used the STR method as well as a computer algorithm to find similarity alignments between the victim DNA, and the Identification of Individuals
DNA Indexing System, which work directly with law ~ missing persons and casualties
enforcement agencies to match registered DNA samples to victim’s family DNA. With the use DNA forensic tool, investigators were able track down the missing passengers on the flight, and identify lost loved ones.
In 2001, after the attacks on the World Trade Center, DNA forensics was used to identify the missing victims of the bombings. Forensics team combed through **ex. U.S. Armed Services
samples found at crime scenes. Veterinary Applications
DNA fingerprinting was first used to provide the rubble to find any piece of remaining evidence to link the dead to their family members. Dental, blood, and hair samples were collected from ground zero, and
compared to the DNA samples provided by family members in the form of hair brushes, tooth brushes, and other items that may have contained traces of biological ~ parentage testing of purebred animals
evidence in a 1986 Pennsylvania case. Samples were ~ wildlife studies
extracted from corpses involved in the case, but much of tissue which DNA could have been extracted out of.
~ identification of inheritance patterns of genetic diseases
the samples had been degraded. A technique called the ~ identification of genetic patterns in populations
Polymerase Chain Reaction (PCR) developed in the early ~ investigate genetic susceptibility of populations to
1980’s allowed for amplification of the limited samples, diseases
which were then used as evidence in the case. In this Agricultural Applications
situation a limited supply of DNA would have been ~ breeding of dairy animals
difficult to generate enough significant evidence since a ~ cultivation of various crops
technique developed in 1980 using restriction enzymes The ability of scientists to use DNA fingerprinting to
would have been the alternative. This shows the importance identify sequencing patterns in many different
of developing techniques that enable scientists to help in organisms is creating new possibilities every day, the
the courtroom environment. Furthermore, refinement of extent of which is still not fully known..
these techniques allowed for the Human Genome Project to
initiate in late 1980’s. Currently, the entire human genome
has been sequenced, but there is still speculation as to the References
number of genes actually present. To the surprise of many http://www.ornl.gov/sci/techresources/Human_Genome/elsi/forensics.shtml#6
http://www.universityscience.ie/pages/scimat_ethical_issues_dna.php
scientists, current findings show that there are ~35,000 http://jme.bmjjournals.com/cgi/content/full/26/4/266
http://www.le.ac.uk/ge/maj4/JoblingGill04.NRG.Forensics.pdf
genes relative to original predictions, but as progress is www.accessexcellence.org/RC/AB/BA/DNA_Fingerprinting_Basics.html
http://en.wikipedia.org/wiki/DNA_testing
made a much better understanding of the human genome www.news.ucdavis.edu/sources/ag_vet_DNA.lasso
http://www.wesleyan.edu/synthesis/GROUP4/FINALVERSIONS/LASTD
can be established. http://www.cambridgenetwork.co.uk/POOLED/ARTICLES/BF_NEWSART/VIEW.ASP?Q=BF_NEWSART_126943
http://www.ornl.gov/sci/techresources/Human_Genome/faq/genenumber.shtml
The benefits of using DNA evidence have been Martin Paul, Johnson Paul, Williams Robin. Genetics and Forensics: Making the National DNA Database. Sci Stud. 2003 ;
16(2): 22–37.
made apparent with the increasing number of criminal cases Clark, Michael. Forensic. The Lanclet. 2005; 366: 1351
Aronson Jay. DNA fingerprinting on trial: the dramatic early history of a new forensic technique. Endeavour 2005: 29(3):

that have been resolved in light of DNA findings. A man in 126-131

McElfresh, Kevin C., Debbie Vining-Forde, and Ivan Balazs. 1993. "DNA-Based Identity Testing in Forensic Science."
BioScience. Vol.43, No. 3, pp.149-157.
Pittsburgh, PA was exonerated from a life sentence in May Neufeld, Peter J. and Neville Colman. 1990. "When Science Takes the Witness Stand." Scientific American. Vol. 262, No.5,
pp.46-53.
2006 for a murder committed in 1989 as new DNA Moody, Mark D. 1989. "DNA Analysis in Forensic Science." BioScience. Vol.39, No.1, pp.31-35.
Marshal, Eliot. 1996. "Academy's About-Face on Forensic DNA." Science. Vol.272, pp.803-804.
evidence established his innocence. Advancements in DNA http://www.aic.gov.au/publications/tandi/ti26.pdf
http://www.nature.com/embor/journal/v7/n4/full/7400669.html
matching have shown to be powerful tools in both the Lynch, Michael. The Discursive Production of Uncertainty: The OJ Simpson 'Dream Team' and the Sociology of Knowledge
Machine
scientific society as well as the justice system. This Social Studies of Science, Vol. 28, No. 5/6, Special Issue on Contested Identities:
Science, Law and Forensic Practice (Oct. - Dec., 1998) , pp. 829-868
particular area of forensics has evolved immensely within Enhanced kinship analysis and STR-based DNA typing for human identification in mass fatality…
http://www.astm.org/cgi-bin/SoftCart.exe/JOURNALS/FORENSIC/PAGES/JFS2003311.htm?E+mystore
the last 2 decades, but there are still many issues that need DNAi: http://www.dnai.org/romanovs/index.html
Timeline: http://www.le.ac.uk/ge/maj4/JoblingGill04.NRG.Forensics.pdf
to be addressed such as ethical questions and unexplained Crime Scene Image:http://las.perkinelmer.com/Content/Images/smallImages/boodalcoholmontage.jpg
PCR Image: http://www.dna-forensic.com/dna-str.html
events in DNA science. There is no doubt that DNA DNA background: http://www.ceul.ufms.br/semanabiologia2005/arquivos/dna.jpg

fingerprinting will be a prominent area of research in the

coming years.
Ethical Issues Problems Occurring in Analysis
One of the major problems with DNA tests becoming common is the issue of privacy. Once a person’s The beauty of the growing field of forensic science is the diversity in the methods of analyzing DNA samples. Given this diversity, if the nature of a sample does not
DNA is sequenced, it is kept on record. Most states do not require that the DNA is destroyed after it is looked allow it to be analyzed with one method then it is probably still useful to other techniques. The most common problem with DNA samples is usually caused by DNA degradation,
at, so the sample may be available at later times for evidence. Stored samples increase the possibility that which alters the structure of DNA so that it cannot be analyzed with the typical RFLP techniques. This can occur from exposure to heat, humidity, sunlight, etc. as well as
someone could get a hold another human being genome. This is causing a stir because it’s increasing the contamination from bacteria and organic molecules from the environment from which the sample was withdrawn. Degradation causes longer regions of DNA to be interrupted.
likelihood that government, insurance companies, employers, schools, banks, could possibly get their hands on As a result, single tandem repeat assays work best for degraded DNA because it involves the amplification of a smaller amount of base pairs, about 150 or less. Using these mini
the information and use it in the future. These organizations could possibly use the information for genetic STRs and amplifying them with 32 cycles of PCR has the advantage of increasing the likelihood of more DNA fragments of the desired alleles surviving. This, in turn, increases
discrimination, not allowing people to obtain loans, work, or get health insurance if they found out that the the chances of retrieving a complete DNA profile. Using longer numbers of base pairs can lead to an imbalance of the alleles during PCR amplification and even dropout of an
person is predisposed to certain illness, or cancer. allele in the results which, obviously, leads to invalid interpretations. Longer sequences have been shown to have significant dropout after two weeks of degradation, as opposed
One place in the world where privacy is becoming a major issue is the UK. Police officials are to 8 weeks for the STRs.
allowed to obtain DNA samples from all suspects in a crime without permission. The UK has the largest DNA Some alternatives to STRs have been in development. One of these methods is the use of single nucleotide polymorphisms, SNPs. These methods have found to be
database in the world. The use of this database involves balancing between the rights of the individual versus useful because they, based on the biochemistry mechanisms of extending primers, can genotype numerous SNPs in a single analysis. However, this requires a large amount of
the right of the state. The UK is having great success with finding criminals that match crimes, but in doing so DNA template and PCR product, whose values are limited by sample amount. Another advantage of SNPs is that they, being single base sites, have much smaller amplicons, but
many believe their tampering with an individual’s rights. the biallelic nature of these makes it difficult to interpret results from a mixed sample, thus requiring a well-balanced assay. One final problem with this method, because it is
Although DNA testing in the UK seems like a good idea, practically speaking it’s not, due to the fact multiplex system, is that it contains several transfers of the sample which can lead to a higher chance of contamination.
that DNA sequencing takes a long time. There is a large build up of samples right now in the UK, so many Once past the step of using PCR to retrieve a complete profile that has not been contaminated, the next issue arises in the discovery of a match. Forensics uses the probability of a
cases have been dismissed, or trials ended before DNA is sequenced. Other countries such as Germany, match and the frequency of alleles in a population to determine the likelihood that the sample from the scene came from a suspect. Degraded DNA almost forces the use of mini
Holland, France, Austria, have also turned to DNA samples for answers but only do testing when individuals STRs for forensic analysis because of its accuracy, but the smaller amount of base pairs and alleles used can mean that the probabilities of a match are higher than those for longer
are suspected of committing serious crimes. Here in the USA, police are unable to force suspects to give sequences. As a result PCR is used to remove a suspect form the scene of a crime rather than place him/her there.
samples due to the 4th amendment. More problems exist with current forensic DNA analysis techniques outside of DNA degradation. One common problem, specifically with RFLP methods, is that of band
Measures must be taken to keep individuals right of dignity and freedom. As stated in the constitution, shift on gels. Band shift is seen as DNA fragments moving across the gel at different speeds on the same gel. This can occur from problems with DNA concentration, faulty gel
people should be given the choice, so many argue that consent should be obtained from each individual, before preparation, salt content in the sample, and contamination. When it comes to determining a match these band shifts could cause a problem because it seems difficult to defend
the DNA sample is taken. People being tested need to be aware of the consequences that will affect their lives, two pieces of DNA as a match if the patterns are slightly different. However, scientists have concluded that this shift is just as likely to a match as away from it.
along with the lives of family members. Another point people are making is certain countries are also not Many problems can arise from the nature of the sample and the environment from which is withdrawn. Standardization of the techniques used to analyze the diversity of
allowing people to move around while being tested, and to object to DNA analysis of their sample. DNA samples will lead not only to consistent results but also consistent conclusions on the matching of two separate DNA samples. If error in an analysis occurs there is most
likely no more of the sample left to use for a second round of analysis. Improving the methods used to analyze the various types of DNA will steer away from inconclusive results
and lead to accurate conclusions in identifying the source of a DNA sample.