FY 2016 DNA Capacity Enhancement and Backlog Reduction Program - Dallas County (TX)

The project will address the need for improvement and expanded DNA testing capabilities in a local forensic DNA laboratory. [redacted due to length] The Institute currently performs testing of nuclear DNA using the short tandem repeat (STR) testing method. [redacted due to length] Amplicon size for the STR loci currently used in the laboratory is 100-400 base pairs in length. Due to the relatively large amplicon size, there are numerous instances where the ability to generate a complete profile from degraded DNA samples is limited by insufficient size of the target DNA fragments. In this project, we will validate and implement new procedures for two (2) new kits specifically designed to increase the recovery of genetic information from degraded samples: the AmpFlSTR® MiniFiler® PCR Amplification Kit and the HID-Ion AmpliSeqTM Identity Panel. Validation and implementation of these kits will allow the Institute to obtain DNA profiles for many samples containing degraded DNA.

We will also validate and implement the HID-Ion AmpliSeqTM Ancestry Panel, and panel of 165 SNPs designed to provide biogeographic ancestry information about the contributor of the DNA profile to the evidence sample. Validation and implementation of this panel will greatly enhance the services we currently provide to law enforcement agencies by providing them information as to the genetic ancestry of a suspect, as well as, a prediction of his/her physical traits. [redacted due to length]

The second goal of the project is to increase testing capacity in both DNA analysis and evidence screening. The laboratory currently utilizes the Quantifiler® Human DNA Quantification Kit for human DNA quantitation. One limitation of the Quantifiler® kit is that it detects total human genomic DNA. There are some types of evidence samples that contain a mixture of female and male DNA (e.g., sexual assault evidence when the assailant is vasectomized or is for other reasons aspermatozoic). Y-chromosome STR testing is a valuable technique for the analysis of these types of evidence samples. The Quantifiler® kit does not allow for the differentiation between male and female DNA. [redacted due to length] In this project, we will evaluate the Quantifiler® Trio DNA Quantitation Kit and Plexor® HY System to determine the appropriate quantification kit to be validated and implemented by the laboratory. Analysis of DNA samples using either of these kits would streamline case work flow, reduce the amount of DNA extract consumed by analysis, and increase downstream analysis success rates.

The purchase of a microscope and alternate light source with imaging capabilities will increase the laboratory’s screening capacity, improve the quality of the supporting documentation of the testing performed, and streamline the laboratory’s current verification process for microscopic examination of sexual assault evidence. A 3500xL Genetic analyzer will be purchased to increase the capacity of the laboratory to perform DNA analysis of casework samples. Six GeneMapper ID-X software licenses will be purchased to analyze forensic DNA evidence profiles and five computer workstations will be purchased to perform probabilistic genotyping of DNA profiles using the STRmix software package. [redacted] nca/ncf