Research Lab: Houston

Dr. Rachel Houston is currently an Associate Professor at Sam Houston State University in Huntsville, TX. In Fall of 2018, Dr. Houston joined the department of Forensic Science as an Assistant Professor.

She received her undergraduate degree in Biology at the University of Texas at Dallas in 2013 before pursuing a PhD in Forensic Science at Sam Houston State University. In May of 2018, Rachel completed her PhD, which was a funded Graduate Research Fellowship sponsored by the National Institute of Justice that focused on developing genetic assays to aid in the individualization and origin determination of marijuana samples.

Dr. Houston is also an active member of the American Academy of Forensic Sciences (AAFS) and the Association of Forensic DNA Analysts and Administrators (AFDAA).

Dr. Houston's research interests include a variety of topics that range from innovative technologies applied to human identification to non-human forensic genetics. Current projects at SHSU include the optimization of front end DNA collection for "touch" samples, the evaluation of an innovative DNA collection device with mock disaster victim identification (DVI) type samples, the development of an assay for rapid detection and identification of bio-threats, and the development of genetic assays to predict a Cannabis sample's crop type (hemp vs. marijuana) and geographical origin.

Dr. Houston's research goals include evaluating front end processing of evidence and the applicability of direct PCR specifically with "touch" samples. More research is needed to evaluate which types of evidence can and should be processed with a Direct to PCR workflow.

Additionally, Dr. Houston would like to continue to expand the field of forensic plant science by developing more genetic assays for identification and individualization of plants of forensic interest. Specially, plants that are highly trafficked for their psychoactive properties are the top priority. Example plants of interest include Cannabis sativa (marijuana), Papaver somniferum (opium poppy), Erythroxylum coca (cocaine), and Mitragyna speciose (kratom).

Other research interests include exploring the use of alternate DNA markers (INNULs, INDELs, SNPs) and Massively Parallel Sequencing (MPS) for human identification (HID) and intelligence purposes.

• Lab Work
• Triathalon
• AFDAA 2018

Research Updates

• Houston Research Group at ISHI 2024

  September 2024

  

  Congratulations to my current students that presented their work at the ISHI meeting in San Antonio, TX on September 24-25, 2024.

  PhD student, Jennifer Snedeker, presented a poster titled "28 Days Later: DNA Recovery from Chemically Treated Human Remains”. PhD student, Julia Wang, presented a poster titled “Securing the Future: Long-term Stability of Y-Screened Sexual Assault Evidence”. PhD student, Cesar Cantu, presented a poster titled “Recovery of Human DNA from Maggots”. PhD student, Ahana Chatterjee, presented a poster titled “Evaluating Direct Lysis and Swabbing Techniques for Improved DNA Typing from Adhesive Surfaces.”

  In addition, Dr. Houston gave a poster presentation titled “Streamlining Skeletal Remains Processing in Forensic Laboratories: Developing a Decision Tree for Capillary Electrophoresis and Next Generation Sequencing Platforms”.

• Houston Research Group at AAFS 2024

  February 2024

  

  Congratulations to my current and past students that presented their work at the AAFS meeting in Denver, CO on February 21-23, 2024.

  Post-doctoral student, Dr. Ya-Chih (Jessica) Cheng, presented a poster titled "Differentiating Marijuana From Hemp Using an NGS Panel and Rapid Genotyping Assays Targeting Cannabinoid Synthase Genes". PhD student, Jennifer Snedeker, presented a poster titled "An Examination of the EZ2 Connect Fx for Extra-Large Volume DNA Extraction and Purification From Skeletal Samples". PhD student, Julia Wang, presented a poster titled "Into the “Sexome”: Genital Microbiome Transfer and Applications".

  In addition, Dr. Houston gave an oral presentation titled “Streamlining Degraded Sample Processing in Forensic Laboratories: Developing a Decision Tree for Capillary Electrophoresis and Next Generation Sequencing Platforms”.

• PhD Student Cesar Cantu Presents at ESA 2023

  November 2023

  

  Cesar Cantu will present "COI DNA Barcoding of Forensically Relevant Insects Collected during Decomposition in Huntsville, TX, USA" at the Entomological Society of America in National Harbor, Maryland.

• Houston Research Group at ISHI 2023

  September 2023

  

  Congratulations to Ya-Chih "Jessica" Cheng and Natalia Czado for their poster presentations at the International Symposium on Human Identification (ISHI). Jessica presented over one phase of her dissertation research titled "Differentiating Marijuana from Hemp using an NGS Panel and Rapid Genotyping Assays Targeting Cannabinoid Synthase Genes", and Natalia Czado gave a presentation over a collaborative project with QIAGEN titled "Developing a Decision Tree for Streamlining Degraded Sample Processing Across Capillary Electrophoresis and Next-Generation Sequencing Platforms in Forensic Laboratories."

• Dr. Houston's PhD Students Present at ISHI 2023

  September 2023

  

  Ya-Chih "Jessica" Cheng will present "Differentiating Marijuana from Hemp using an NGS Panel and Rapid Genotyping Assays Targeting Cannabinoid Synthase Genes" and Natalia Czado will give a presentation on "Developing a Decision Tree for Streamlining Degraded Sample Processing Across Capillary Electrophoresis and Next-Generation Sequencing Platforms in Forensic Laboratories."

• Eight students from Dr. Houston’s lab group present their work at AAFS

  February 2023

  

  Congratulations to my current and past students that presented their work at the AAFS meeting in Orlando, FL on February 13-18, 2023.

  PhD student, Lucio Avellaneda, gave an oral presentation titled “The Development of a Five-Dye Insertion/Deletion (INDEL) Panel for Human Identification”. My former PhD student, Dr. Kari Graham, presented an oral presentation titled “The Intraspecies Variation of Commercially Available Kratom Products in Common DNA Barcode Region”. PhD student, Julia Wang, presented an oral presentation titled “When and “Y” to Screen With QIAGEN® Investigator® Casework GO!”. PhD student, Ya-Chih Cheng, presented an oral presentation titled “The Development of a Next Generation Sequencing Panel Targeting Cannabinoid Synthase Genes to Distinguish Between Marijuana and Hemp”. PhD student, Cesar Cantu, gave an oral presentation titled “The Recovery of Human DNA From Fly Larvae”. PhD student, Damani Johnson, gave an oral presentation titled “The Evaluation of the ForenSeq™ MainstAY Kit for Mixed Forensic DNA Samples”.

  PhD student, Natalia Czado, presented a poster titled “The Optimization of Single Nucleotide Polymorphism (SNP) SNaPshot™ Multiplexes to Distinguish Fiber and Drug-Type Cannabis Sativa”. PhD student, Jennifer Snedeker, presented a poster titled “The Evaluation of Demineralization Parameters for DNA Extraction Methods From Skeletal Remains”.

• Julia Wang Presents at ISHI

  October 2022

  

  Congratulations to PhD student, Julia Wang, for two poster presentations at the International Symposium on Human Identification in Washington D.C. The first poster was titled “The Y’s and How’s of Screening with QIAGEN Casework GO!”. The second poster was titled “If the Trap Fits: Immunomagnetic Isolation of Spermatozoa”.

• Six PhD students present their research at ISFG

  September 2022

  

  Six PhD students presented their research at the International Society of Forensic Genetics (ISFG). The 29th Congress of ISFG was held on August 29 – September 2, 2022, in Washington D.C.

• Julia Wang wins Threesis competition hosted by ISHI

  August 2022

  

  PhD student, Julia Wang, wins Threesis competition hosted by the International Symposium on Human Identification (ISHI). Julia won a cash prize and a pizza party for the entire lab. The goal of this competition was for competitors to refine their communication skills. To check out Julia’s research go to this link: https://youtu.be/t3X6CZcuLsI.

• Natalia Czado and Julia Wang Present their Research at AFDAA

  July 2022

  

  Congratulations to PhD students, Natalia Czado and Julia Wang, for their first oral presentation at the Association of Forensic DNA Analysts and Administrators (AFDAA) conference in Houston, TX. Natalia Czado presented her research titled “Evaluation of Metal Ion and DNA Recovery from the Surface of Brass Ammunition to Improve STR Profiling”. Julia Wang presented her research titled “Mind Your X’s and Y’s: Screening with QIAGEN Casework GO!”.

• Dr. Ryan Gutierrez and Dr. Madeline Roman Publish in Science & Justice

  July 2022

  

  Graduated PhD students, Dr. Ryan Gutierrez and Dr. Madeline Roman, published their findings in Science & Justice. The publication was titled “Detection and analysis of DNA mixtures with the MiSeq FGx”. This publication was a collaboration between Dr. Houston and Dr. Kalafut that looked at how mixture detection is affected by next generation sequencing. This paper found that next generation shows promise in terms of detecting DNA mixtures but improvements in interpretation software need to occur prior to implementation. Available via DOI: https://www.sciencedirect.com/science/article/pii/S1355030622000971

• Dr. Kari Graham Publishes in International Journal of Legal Medicine

  June 2022

  

  Recently graduated PhD student, Dr. Kari Graham, published their findings in International Journal of Legal Medicine. The publication was titled “Evaluation of chloroplast DNA barcoding markers to individualize Papaver somniferum for forensic intelligence purposes”. This study showed that the regions trnH-psbA and petA-psbJ have promise for utility in individualization for both inter- and intra-species individualization of opium poppy. Available via DOI: https://link.springer.com/article/10.1007/s00414-022-02862-6

• Dr. Houston's group publishes in Forensic Science International: Genetics

  May 2022

  

  Congratulations Dr. Ryan Gutierrez for their first author publication in Forensic Science International: Genetics. The article is titled “Assessment of the ForenSeq mtDNA control region kit and comparison of orthogonal technologies”. This study assessed the ForenSeq® mtDNA Control Region Kit, MiSeq FGx®, and Universal Analysis Software (UAS) to better define the performance and limitations of the system with forensically relevant samples to provide data for its transition into practice. Available via DOI: https://www.sciencedirect.com/science/article/pii/S187249732200062X?via%3Dihub

• Dr. Kari Graham Graduates with PhD in Forensic Science

  May 2022

  

  Congratulations to my PhD student, Kari Graham for graduating with a PhD dissertation titled “Forensic applications of DNA sequencing to combat drug trafficking and biothreats”. Dr. Graham is now a DNA Analyst at the UNT Center for Human Identification.

• Sabrina Hodge and Rachel Last Graduate

  May 2022

  

  Congratulations to my two master’s students, Sabrina Hodge and Rachel Last, that graduated with their Master of Science in Forensic Science. Sabrina now works at Harris County Institute of Forensic Sciences as a Serology/DNA Operations Technician. Rachel now works at the Armed Forces DNA Identification Lab as a Forensic Scientist 1.

• Rachel Last, Julia Wang, and Sabrina Hodge Defend Master's Capstones

  April 2022

  

  Rachel Last, Julia Wang, and Sabrina Hodge successfully defended their capstone research. Congratulations to all.

• First Annual Team DNA Field Day

  April 2022

  

  Professors and graduate students celebrated the first annual team DNA field day. The day was filled with many games and foods. It was the perfect way to de-stress before the upcoming capstone presentations.

• Julia Wang wins second place in 3 Minute Thesis Competition at SHSU

  April 2022

  

  PhD student, Julia Wang, won second place at the 3 Minute Thesis (3MT) competition hosted by SHSU. Her 3MT was titled “Trapping Sperm to End the Sexual Assault Kit Backlog”. Congratulations Julia!.

• Dr. Kari Graham Successfully Defends Dissertation

  March 2022

  

  Congratulations to our newly minted PhD, Dr. Kari Graham. Dr. Graham defended her dissertation titled “Forensic Applications of DNA Sequencing to Combat Drug Trafficking and Biothreats”.

• Damani Johnson presents his research at ACJS

  March 2022

  

  Congratulations to PhD student, Damani Johnson, for his poster presentation at the Academy of Criminal Justice Sciences (ACJS) in Las Vegas, NV. This presentation was a collaboration between the Department of Forensic Science and the Department of Criminal Justice and Criminology. The poster was titled “Exploring Environmental and Genetic Influences on Substance Abuse Behavior”.

• Dr. Houston's group publishes in Journal of Forensic Science

  March 2022

  

  Congratulations Dr. Madeline Roman and Jessica Cheng for their publication in the Journal of Forensic Sciences. The article is titled “Evaluation of tetrahydrocannabinolic acid synthase polymorphisms for distinguishing between marijuana and hemp”. This study was a collaboration between Dr. Houston and Dr. Kerrigan that looked at both genetic and chemical data from cannabis plant material. This study found that current genetic methods to differentiate marijuana and hemp are insufficient. Available via DOI: https:https://onlinelibrary.wiley.com/doi/10.1111/1556-4029.15045

• Houston Group presents their research at the AAFS 74th Annual Conference

  February 2022

  

  Congratulations to my current and past students that presented their work at the AAFS meeting in Seattle, WA on February 21-25, 2022. Jennifer Snedeker presented an oral presentation titled “The Optimization of the InnoXtractTM Extraction and Purification System for DNA Extraction from Skeletal Samples and Analysis of Subsequent Downstream Processing Methods”. Lucio Avellaneda presented an oral presentation titled “The Forensic Utility of the ForenSeqTM MainstAY Kit with Challenging Samples”. Additionally, four students, Kari Graham, Jessica Cheng, Samantha Davis, and Cesar Cantu, presented their research as poster presentations.

• Congratulations to Cesar Cantu for a first author publication

  January 2022

  

  Congratulations to my PhD student, Cesar Cantu, for a first author publication in the Journal of Forensic Sciences. The article is titled “Comparison of DNA extraction techniques for the recovery of bovine DNA from fly larvae crops”. Our results showed that EZ1 DNA Investigator extraction yielded the highest DNA concentrations from larvae crops. We propose that this method could be applied to recover human DNA from fly larvae feeding on decomposing cadavers. Available via DOI: https://onlinelibrary.wiley.com/doi/10.1111/1556-4029.15010

• Dr. Houston’s group publishes paper direct amplification strategies for disaster victim identification

  August 2021

  

  This paper was co-authored with my former master’s students and Dr. Hughes. This research was published in Forensic Science International: Genetics. The findings in this study suggest swabs could facilitate sample collection and storage under challenging conditions in DVI scenarios and that direct amplification could be used to supplement traditional extraction/quantification workflows for faster and easier processing during early decomposition. Available via DOI: https://doi.org/10.1016/j.fsigen.2021.102588

• Dr. Ryan Gutierrez Graduates with PhD in Forensic Science

  August 2021

  

  Congratulations to my PhD student, Ryan Gutierrez for graduating with a PhD dissertation titled “Alternative Sample Processing Techniques for Rootless Hair Shafts and Other Challenging Samples”.

• Congratulations to Ryan Gutierrez for a first author publication

  March 2021

  

  Congratulations to my PhD student, Ryan Gutierrez, for a first author publication in the Journal of Forensic Sciences. The article is titled “Novel extraction chemistry and alternative amplification strategies for use with rootless hair shafts”. Our results showed that Compared with the capillary electrophoresis-based amplification chemistries tested, the ForenSeq™ DNA Signature Prep chemistry paired with massively parallel sequencing was the most discriminatory amplification strategy tested for rootless hair shafts. Available via DOI: https://doi.org/10.1111/1556-4029.14763

• Congratulations to Ya-Chih (Jessica) Cheng for a first author publication

  August 2020

  

  Congratulations to my PhD student, Jessica Cheng, for a first author publication in the International Journal of Legal Medicine. The article is titled “Evaluation of the trnK-matK-trnK, ycf3, and accD-psal chloroplast regions to differentiate crop type and biogeographical origin of Cannabis sativa”. This study demonstrated the applicability of organelle markers for the determination of crop type and biogeographic origin of Cannabis sativa. However, a more extensive database is needed to evaluate the true discriminatory power of these markers. Available via DOI: 10.1007/s00414-021-02518-x