My Research

The Pfau Lab

The main focus of my research is population genetics, often with an emphasis on conservation biology. Small mammals have been the primary subject of my research; but I have broadened my taxonomic coverage to include frogs, fish, insects, crabs, and plants.

Ongoing Projects

• Population genetics and mitochondrial genomics of pocket gophers of the genus Geomys
• Geographic distribution of shrews of the genus Blarina using DNA sequencing to identify cryptic species
• Conservation genetics of the crawfish frog, Lithobates areolatus
• Distribution of Sigmodon hispidus in Mexico
• Species status of the bumblebees Bombus pensylvanicus and B. sonorus

Student Research Opportunities

Undergraduate and graduate students working in my lab gain hands-on experience in using modern, molecular genetic and field techniques. Genetic techniques that students have the opportunity to use include DNA extraction and amplification via polymerase chain reaction and use of our automated genetic analysis system for DNA sequencing and fragment analysis. My lab is also using high-throughput DNA sequencing for genomic analysis. Students benefit not only from hands-on research experience, but also by gaining a working understanding of population-genetic theory and evolutionary biology.

Student research is not limited to the lab. The opportunity also exists for students to be involved in collecting organisms from their native habitat. Field techniques provide the foundation for the broad and rapidly expanding field of molecular ecological research and conservation genetics. Field research allows students to gain an intimate understanding of the habitat preferences, geographical distribution, and behavior of the organisms that they will be studying in the laboratory.

Students also have the opportunity to present their research at local, regional, national, and international conferences.

Additionally, much of my research is done in collaboration with faculty and graduate students at other universities, providing students the opportunity to meet and work with scientists from universities other than Tarleton.

Student Research

• 2020-2021
  • Nicole Armitage (undergrad) – Assessment of a contact zone between two species of pocket gopher
• 2019-2020
  • Nadia Samiya (grad) – Population genetics of the pocket gopher Geomys texensis
  • Haley Greenia (grad) – Mitochondrial genomics of the pocket gopher genus Geomys
  • Shady Kuster (undergrad) – Mito-nuclear genetics of the pocket gopher Geomys breviceps
  • David Kiker (undergrad) – Mitochondrial genomics of the Texas kangaroo rat Dipodomys elator
  • Josef Leachman (undergrad) – Impact of soil type on the distribution of the pocket gopher Geomys texenis
• 2016-2018
  • Seth Hamby (grad) – Conservation genetics and ecology of the Comanche peak prairie clover (Dalea reverchonii) 
  • Alberto Luciano (undergrad) – genetic identification of gophers (Geomys) along the Colorado river using AFLP
  • Kimberly Norris (undergrad) – methods to avoid amplification of nuclear mitochondrial inserts (NUMTS) in Geomys
  • Jason Villarett-Dean (undergrad) -genetic identification of shrews (Blarina) in Kansas using mtDNA sequencing
  • Juana Marin (undergrad) –  genetic identification of gophers (Geomys) along the Colorado river using AFLP
  • Monica Villalpando (undergrad)
• 2014-2016
  • Hunter Glisson-Warner (undergrad) – assessment of genetic structure within the pocket gopher, Geomys arenarius
  • Elizabeth Gilliland (undergrad) – population genetics of the state-threatened Texas kangaroo rat (Dipodomys elator)
• 2013-2014
  • Wesley Wiegreffe (undergrad) genetic analysis of potential hybridization in red and blacktail shiners
  • Andria Beal (undergrad) – genetic analysis of the cotton rat (Sigmodon hispidus) hybrid zone
  • Tim Huebner (grad) – Genetics of an invasive mud crab (Rhithropanopeus harrisii) in Texas reservoirs
• 2012-2013
  • Wesley Wiegreffe (undergrad) genetic analysis of potential hybridization in red and blacktail shiners
  • Andria Beal (undergrad) – genetic analysis of the cotton rat (Sigmodon hispidus) hybrid zone
  • Caryne Hampton (undergrad) – genetic analysis of the cotton rat (Sigmodon hispidus) hybrid zone
  • Jacody Coronado (undergrad) – morphometrics of the shrews Blarina brevicauda and B. hylophaga
  • Cheri Porter – DNA isolation from plants
  • Tim Huebner (grad) – Genetics of an invasive mud crab (Rhithropanopeus harrisii) in Texas reservoirs
• 2010-2012
  • Ben Stevens (grad student) sequenced DNA of the bacterial genus Bartonella in several species of cotton rats in order to determine patterns of diversity within this group of bacteria.
  • Lee Richardson (grad student) used genetic data to map the geographic distribution of two genetic lineages of Sigmodon hispidus and examine patterns of hybridization.
  • Allison Love (grad student) used DNA fingerprinting (AFLP) to study hybridization of red and black-tailed shiners in the Paluxy and Bosque rivers.
• 2011-2012: Alex Trott (undergrad student) generated DNA fingerprinting (AFLP) data for a population genetic study of the Texas mouse.
• 2009-2011
  • Ashley Kozora (grad student) determined population genetic structure of the gopher Geomys arenarius in New Mexico and west Texas.
  • Sara Zeisler, an undergraduate, sequenced DNA from cotton rats (Sigmodon hispidus) to determine geographic distribution of two genetic lineages and to uncover patterns of hybridization.
  • Stephanie Painter (grad student) used real-time PCR to quantify the amoeba Naegleria fowleri and E. colii in Lake Granbury.
  • Jordan Sparkman (undergraduate) focused primarily on development of microsatellite markers for the cotton rat.  Becca Peters  sequenced mitochondrial DNA of shrews in order to study the degree of introgression between two hybridizing species.
• 2008-2009: Rachel Seay and Rece Laney sequenced mitochondrial and Y-chromosome DNA, respectively, of the hispid cotton rat in order to locate and characterize a hybrid zone between two genetic lineages of this species.  Becca Peters sequenced mitochondrial DNA of shrews in order to study the degree of introgression between two hybridizing species.  Jordan Sparkman developed microsatellite markers for the cotton rat.
• 2007-2008: Terry Johnson completed his Master’s degree for which he used AFLP analysis to examine patterns of genetic diversity and divergence of Peromyscus attwateri populations across the geographic distribution of this species. Rachel Seay and Rece Laney sequenced mitochondrial and Y-chromosome DNA, respectively, of the hispid cotton rat in order to locate and characterize a hybrid zone between two genetic lineages of this species.  
• 2007 – Undergraduate students Bethany Stevens and Alicia Sanders isolated microsatellite loci from Sigmodon hispidus using the FIASCO technique. They sequenced DNA and designed and tested primers for use in PCR amplification of the microsatellite loci that they identified.
• Kristin Denton completed her Master’s degree. Her research focused on examining the genetic diversity of an immune response gene (MHC-DQA) in two closely-related rodent species: Peromyscus attwateri and P. boylii.
• Caleb Phillips completed his Master’s degree at Tarleton and obtained his PhD at Purdue University. While at Tarleton, Caleb examined genetic diversity in cotton rats (Sigmodon hispidus) using AFLP analysis and has detected hybridization between two divergent lineages in eastern Texas.
• 2006 – Undergraduate students included Calvin Henard, Sadie Goodwin, and Endra Sookor. Calvin sequenced mitochondrial DNA from east Texas Sigmodon to determine which individuals belonged to divergent eastern or western lineages. This project is focusing on clarifying the nature of a hybrid zone between these two lineages. Sadie sequenced mitochondrial DNA to examine the population genetic structure of deer mice (Peromyscus maniculatus) from islands off the coast of California and Baja California. Endra designed and testing primers to amplify a gene involved in sperm-egg recognition in the cotton rat.
• 2005 – Calvin Henard sequenced mitochondrial DNA from east Texas Sigmodon to determine which individuals belonged to divergent eastern or western lineages. Valeska Valderas used AFLP to estimate levels of genetic diversity in the Palo Duro mouse (Peromyscus truei comanche) from Palo Duro Canyon, TX. Jennifer Linkenauger sequenced DNA from the pinyon mouse (Peromyscus truei) to address questions of phylogeography among populations from Texas, Oklahoma, and New Mexico. Yvette Vaughan worked on a PCR optimization project for a Heredity lab exercise.
• 2004 – Terry Johnson used AFLP analysis to examine patterns of genetic diversity and divergence of Peromyscus attwateri populations across the geographic distribution of this species.
• Julia Ranger conducted microsatellite analysis on Peromyscus maniculatus from Baja California and sequenced mitochondrial DNA from the Texas mouse (P. maniculatus).
• Christina Dobson attempted to extract DNA from skulls of museum voucher specimens for the purpose of sequencing mitochondrial DNA.
• Spring/Fall 2003 – Lin Winton used single-strand conformation polymorphism analysis and DNA sequencing to identify MHC-DQA alleles from Peromyscus maniculatus and also used microsatellite analysis to compare levels of genetic diversity among island and mainland populations of Peromyscus maniculatus from Baja California.
• Spring 2003 – Caleb Phillips, Lauren Adams, and Kyle Jordan fine-tuned AFLP analysis for use in evaluating levels of genetic diversity in Peromyscus and Sigmodon species.
• Fall 2002 – Ken Brooks used microsatellite analysis to determine level of genetic diversity in a population of Peromyscus maniculatus from Oklahoma.
• Spring/Summer 2002 – Lindsay Smith, Jason Magonye and Ken Brooks used microsatellite analysis to determine genetic diversity and effective population sizes of several Peromyscus populations from southern California and Baja California.
• Spring/Fall 2001 – Josh Combs tested PCR reactions and experimented with several techniques to observe parasites in insects for use in my Parasitology lab.