20th International Symposium on Human Identification

Description The newly released PowerPlex ESX and ESI Systems contain the loci recommended by the European Network of Forensic Science Institutes (ENFSI). This presentation will describe the various studies that were conducted at NIST to assess the performance of these systems

Description Over the past twenty years, DNA analysis has revolutionized forensic science, and has become a dominant tool in law enforcement. Today, DNA evidence is key to the conviction or exoneration of suspects of various types of crime, from theft to rape and murder. However, the disturbing possibility that DNA evidence can be faked has been overlooked. It turns out that standard molecular biology techniques such as PCR, molecular cloning, and recently-developed whole genome amplification (WGA), enable anyone with basic equipment and know-how to produce practically unlimited amounts of in vitro synthesized (artificial) DNA with any desired genetic profile. This artificial DNA can then be applied to surfaces of objects or incorporated into genuine human tissues and planted in crime scenes.

Description Recently, there has been much discussion of the practice of categorising DNA profiles according to whether they are deemed to be low-copy-number (LCN) or ‘conventional’. Various authors have previously attempted to provide definitions based on modifications designed to enhance the sensitivity of the existing techniques (e.g. elevated cycle number, post PCR manipulation) whilst others have attempted a classificatory system based on the measured amount of template DNA input to the PCR. We believe that such an approach is neither helpful nor indeed possible. This is because there is no possible natural delineator that can be used. The transition between the two ‘states’ is gradual rather than sudden and is independent of the methodology utilized to prepare the DNA profile. Rather it is preferable to work towards a single integrated interpretative statistical approach that can be applied universally.

Description The PowerPlex® 16 HS System is an updated version of the PowerPlex® 16 System; while the primers and dyes remain unchanged, it introduces an enhanced buffer system that includes hot-start Taq DNA polymerase and ensures robust performance. Due to the modification of the reaction mix, a multi-laboratory developmental validation study was completed to document performance capabilities and limitations for the revised assay. Data within this validation was generated by eight laboratories and served as the basis for the following conclusions: Genotyping of single-source samples was consistent across a large range of template DNA concentrations with most laboratories obtaining complete profiles at 62.5pg. Mixture analyses showed that over 90% of minor alleles were detected at 1:9 ratios. Optimum amplification cycle number was ultimately dependent on the sensitivity of the detection instrument and could be adjusted to accommodate a range of DNA template concentrations. Reaction conditions including volume and annealing temperature as well as the concentrations of primers, Taq DNA polymerase, and magnesium were shown to be optimal and able to withstand moderate variations without affecting multiplexed STR amplification. The robustness of the enhanced buffer systems tolerates a much higher concentration of common PCR inhibitors and allows for direct amplification from DNA collection card punches. Finally, data from non-probative samples and concordance studies showed consistent results when comparing the PowerPlex® 16 HS System with the PowerPlex® 16 System as well as other commercially available systems. The combined sensitivity and flexibility of the PowerPlex® 16 HS System make it a great option for both databasing and casework labs.

Description On March 3, 1989, Debbie Smith was kidnapped from her home while her husband, a police officer, was sleeping upstairs. She was dragged into the woods behind her Williamsburg , Virginia home and raped. The rapist threatened Debbie not to tell, and reminded her that he knew where she lived. Bravely, Debbie went forward and told her husband Robert of the assault. The rape was officially reported and she consented to a forensic exam.

The traumatic effect of the assault remained with Debbie and her family for six and ½ years, and then her perpetrator was finally caught through a DNA database known as CODIS (Combined DNA Index System). The man who sexually assaulted her had abducted and robbed two other women. Their attacker was identified through an ATM photo where he made them take out their money. When his DNA was put into the system there was a match. Debbie’s attacker was convicted of rape, abduction, robbery, burglary and larceny. He was sentenced to two life terms plus 25 years in prison.

Because of the suffering Debbie and countless other victims of sexual assault have faced, legislation has been passed to improve investigations and services for this crime. The Debbie Smith Act, now part of the Justice For All Act of 2004, was signed into law on October 30, 2004.

Description Forensic DNA-typing is intensively used for law enforcement purposes all over Europe. Because of different “historical” structures national policies and database-management are highly heterogeneous among states. Basing on the European Standard Set of Loci (ESS) and carefully designed communication tools, a network of international DNA data exchange has been established. The “Pruem-Treaty” is the ancestor of an EU-wide data exchange, showing the feasibility of connecting a conglomeration of national databases and matching tools. In light of the huge amount of data to be exchanged among 27 European countries additional requirements concerning the ESS arise. In a concerted action the European Network of Forensic Science Institutes (ENFSI) assessed additional markers that increase both power of exclusion and quality of stain typing results. STR-Multiplex manufacturers are challenged by adopting these markers and customizing existing kits for the European market.

Description William Dillon was freed from a Florida prison in late 2008 after serving nearly 27 years for a murder DNA proves he didn’t commit. He was wrongfully convicted in 1981 based on a questionable eyewitness identification, unreliable testimony from the handler of a scent-tracking dog and testimony from a jailhouse informant. In this interview, Dillon describes the experience of being wrongfully convicted and the role that DNA typing played in finally gaining his release.

Description Is the King really dead, or is he living under an assumed name? Does he have progeny in addition to Lisa Marie? This presentation explores how DNA analysis was used to clear up the confusion.

Description Much has changed since the early days of DNA typing. From serology to RFLP to STR analysis, the discipline of DNA typing has become much more powerful and precise. This talk details the early underpinnings of DNA analysis and explores where future technologies might lead.

Description Evidence submitted for DNA analysis can be recovered from a variety of biological samples including blood, saliva, or semen stains on different substrates, body surface swabs, hair, bones, and finger nail scrapings. Forensic analysts seek technologies to maximize the quality of results obtained and increase success rate of obtaining a DNA profile from these types of samples. Incorporating mini-STRs and/or more discriminating loci into a multiplex assay and modifying PCR reaction components and conditions are amongst the options available to help improve recovery of information from a biological sample.

This presentation will highlight the development of next generation STR assays which through the inclusion of new loci and improvements in amplification chemistry, deliver enhanced performance on the challenged and compromised samples most commonly encountered during casework investigations while still providing robust and reliable DNA profiles free of artifact peaks which may complicate interpretation.

Description Technology continues to propel the evolution of forensic. DNA analysis and its applications. From simple PCR methods to high throughput instrumentation and robotics, the forensic community has embraced innovative molecular tools for more than two decades now. While not as far reaching as fragment length analysis, DNA sequencing of forensically-relevant loci has played a significant and successful role in solving criminal cases, and cases of human remains identification. The technology of choice began with Sanger dideoxy-terminator-based sequencing in the 1980’s, and while the instruments used to separate the products of a sequencing reaction have improved over time, the chemistry has remained relatively unchanged. However, we are currently transitioning from the Sanger era of DNA sequencing, and have embarked on the journey of cyclic-array, hybridization-based, nanopore and single molecule sequencing, all commonly referred to as Next Generation Sequencing (NGS). Applications of NGS are having an immediate impact on medical genetics, biodiversity and basic molecular research. Given the imminent prospects of a $1000 human genome sequence, the potential impacts are far reaching and will shape personalized medicine in the near future. So, how will NGS be applied in forensics?

Description Skeletal remains, teeth, hair, and fingernails are challenging forensic samples in which typeable DNA tends to persist longer than in soft tissues. The structure of these biological materials protects DNA - to a certain extent - from oxidative and hydrolytic damage. Even with the protection afforded by these matrices, these types of forensic evidence samples tend to contain limited amounts of DNA, as they do incur DNA damage and degradation due to environmental, bacterial, and post-mortem insults. Moreover, several components that co-purify with DNA from bone, hair, and teeth can also act as potent inhibitors of PCR, such as collagen, calcium ions, melanin, and humic acids. In order to access the available genetic material, matrix- embedded DNA must be released and PCR inhibitors efficiently removed. Pressure Cycling Technology (PCT) is a cutting-edge, platform technology that uses rapid cycles of hydrostatic pressure between ambient and ultra high levels to control biomolecular interactions. In particular, PCT can be used to effectively and efficiently disrupt tissues and cells to extract DNA and other molecules of interest.

Description The recent NAS report raised many questions about the state of various disciplines within the field of forensics. This presentation explores the findings of the committee and provides advice for forensic laboratories to implement recommendations from the report.

Description The Wisconsin Innocence Project recently celebrated its tenth year. During this time, the project has exonerated more than a dozen people who were wrongfully convicted. The project’s first exoneration came in 2001, when Chris Ochoa was released from a Texas prison after spending 12 years of a life sentence for a murder he didn’t commit. The presentation focuses on the causes of wrongful convictions and offers suggestions to minimize their occurrence.

Description In 20 years the amount of DNA required for a DNA test has decreased from micrograms to nanograms, the time required has decreased from weeks to hours, and the acceptance of the technology from skeptical to fundamental. However one of the remaining persistent problems is the interpretation of mixtures, that is, multiple individuals within a single sample. We show that by applying GWAs based analysis methods to forensic samples it is possible to resolve individuals within complex mixtures, as well as address other challenging forensic sample types such as in highly degraded samples. Our technology utilizes the cumulative statistical power from genotyping hundreds of thousands of SNPs to analyze single source forensic samples as well as complex mixtures. The data show that it is possible to parse a mixture of a few individuals using as few as several thousand SNPs and mixtures of hundreds of individuals using 300,000 or more SNPs.

Work presented is proprietary and patent pending.

Description Over the past few years the introduction of robotics into the forensic DNA field has enabled both casework and convicted offender laboratories to significantly increase efficiency on routine procedures in both pre-amplification and post-amplification laboratories. However, this increase in efficiency through automation has not yet been realized in the most laborious step of processing a sexual assault evidence collection kit, namely the separation of sperm and epithelial cells during a differential extraction. Internal data indicates that extraction of differential samples represents 30% of all hours worked in a typical sexual assault case and separation is by far the single most labor-intensive step in the process. The introduction of Promega’s Automated Differex™ System for differential separation of epithelial and sperm cells, which separates up to 48 samples at once, has the ability to simultaneously increase both quality and throughput of a laboratory, therefore reducing the backlog of sexual assault kits.