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Dr. Ron Walter, PI

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Ron Walter, PhD

Professor and University Chair in Cancer Research

Director, Xiphophorus Genetic Stock Center

Ron Walter

Office: 419 Centennial Hall, Texas State University, San Marcos, TX

Email: RWalter@txstate.edu

Office Phone: (512)245-0357


Research Website: Molecular Biosciences Research Group

Xiphophorus Genetic Stock Center

Texas State University Dept. of Chemistry and Biochemistry

Bridges to Biomedicine program - undergraduate (NIH R25 GM107759)

South Texas Doctoral Bridge program - Master's (NIH R25 GM102783)

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PhD Florida State University (Tallahassee, FL) Molecular Genetics 1985
MS Florida State University (Tallahassee, FL) Biology 1981
BS Florida State University (Tallahassee, FL) Biology 1979


Recent Publications (last 5 years) (back to top)


Cui R, Schumer M, Kruesi K, Walter R, Andolfatto P, Rosenthal GG. Evolution. 2013 Aug;67(8):2166-79. doi: 10.1111/evo.12099. Epub 2013 Apr 4. Phylogenomics reveals extensive reticulate evolution in Xiphophorus fishes. (PubMed Abstract)

Schartl M*, Walter RB*, Shen Y, Garcia T, Catchen J, Amores A, Braasch I, Chalopin D, Volff JN, Lesch KP, Bisazza A, Minx P, Hillier L, Wilson RK, Fuerstenberg S, Boore J, Searle S, Postlethwait JH, Warren WC. (*contributed equally). Nat Genet. 2013 May;45(5):567-72. doi: 10.1038/ng.2604. Epub 2013 Mar 31. The genome of the platyfish, Xiphophorus maculatus, provides insights into evolutionary adaptation and several complex traits. (PubMed Abstract)

Schumer M, Cui R, Boussau B, Walter R, Rosenthal G, Andolfatto P. Evolution. 2013 Apr;67(4):1155-68. doi: 10.1111/evo.12009. Epub 2012 Dec 20. An evaluation of the hybrid speciation hypothesis for Xiphophorus clemenciae based on whole genome sequences. (PubMed Abstract)

Shen Y, Garcia T, Pabuwal V, Boswell M, Pasquali A, Beldorth I, Warren W, Schartl M, Cresko WA, Walter RB. Comp Biochem Physiol Part D Genomics Proteomics. 2013 Mar;8(1):11-6. doi: 10.1016/j.cbd.2012.10.006. Epub 2012 Nov 9. Alternative strategies for development of a reference transcriptome for quantification of allele specific expression in organisms having sparse genomic resources. (PubMed Abstract)

Pabuwal V, Boswell M, Pasquali A, Wise SS, Kumar S, Shen Y, Garcia T, Lacerte C, Wise JP Jr, Wise JP Sr, Warren W, Walter RB. Aquat Toxicol. 2013 Jun 15;134-135:74-81. doi: 10.1016/j.aquatox.2013.03.003. Epub 2013 Mar 20. Transcriptomic analysis of cultured whale skin cells exposed to hexavalent chromium [Cr(VI)]. (PubMed Abstract)

Kang JH, Schartl M, Walter RB, Meyer A. BMC Evol Biol. 2013 Jan 29;13:25. doi: 10.1186/1471-2148-13-25. Comprehensive phylogenetic analysis of all species of swordtails and platies (Pisces: Genus Xiphophorus) uncovers a hybrid origin of a swordtail fish, Xiphophorus monticolus, and demonstrates that the sexually selected sword originated in the ancestral lineage of the genus, but was lost again secondarily. (PubMed Abstract)


Walter, R.B. (2012) “A Homage to Klaus D. Kallman: The Study of Beautiful Things” In: Viviparous Fishes II, M. C. Uribe and H. Grier (eds.), New Life Publications (ISBN# 0-9645058-9-1), Homestead, Fl. Pp 4-7.

Whitehead A, Dubansky B, Bodinier C, Garcia TI, Miles S, Pilley C, Raghunathan V, Roach JL, Walker N, Walter RB, Rice CD, Galvez F. Proc Natl Acad Sci U S A. 2012 Dec 11;109(50):20298-302. doi: 10.1073/pnas.1109545108. Epub 2011 Sep 26. Erratum in: Proc Natl Acad Sci U S A. 2012 Dec 11;109(50):20774. Genomic and physiological footprint of the Deepwater Horizon oil spill on resident marsh fishes. (PubMed Abstract)

Garcia TI, Shen Y, Crawford D, Oleksiak MF, Whitehead A, Walter RB. BMC Genomics. 2012 Sep 12;13:474. doi: 10.1186/1471-2164-13-474. RNA-Seq reveals complex genetic response to Deepwater Horizon oil release in Fundulus grandis. (PubMed Abstract)

Yang H, Cuevas-Uribe R, Savage MG, Walter RB, Tiersch TR. Zebrafish. 2012 Sep;9(3):126-34. doi: 10.1089/zeb.2012.0737. Epub 2012 Aug 27. Sperm cryopreservation in live-bearing Xiphophorus fishes: offspring production from Xiphophorus variatus and strategies for establishment of sperm repositories. (PubMed Abstract)

Perez AN, Oehlers L, Heater SJ, Booth RE, Walter RB, David WM. Comp Biochem Physiol C Toxicol Pharmacol. 2012 Jan;155(1):81-8. doi: 10.1016/j.cbpc.2011.05.017. Epub 2011 Jun 6. Proteomic analyses of the Xiphophorus Gordon-Kosswig melanoma model. (PubMed Abstract)

Zhang Z, Wells MC, Boswell MG, Beldorth I, Kirk LM, Wang Y, Wang S, Savage M, Walter RB, Booth RE. Comp Biochem Physiol C Toxicol Pharmacol. 2012 Jan;155(1):11-7. doi: 10.1016/j.cbpc.2011.05.015. Epub 2011 Jun 1. Identification of robust hypoxia biomarker candidates from fin of medaka (Oryzias latipes). (PubMed Abstract)

Garcia TI, Shen Y, Catchen J, Amores A, Schartl M, Postlethwait J, Walter RB. Comp Biochem Physiol C Toxicol Pharmacol. 2012 Jan;155(1):95-101. doi: 10.1016/j.cbpc.2011.05.012. Epub 2011 Jun 1. Effects of short read quality and quantity on a de novo vertebrate transcriptome assembly. (PubMed Abstract)

Downs KP, Shen Y, Pasquali A, Beldorth I, Savage M, Gallier K, Garcia T, Booth RE, Walter RB. Comp Biochem Physiol C Toxicol Pharmacol. 2012 Jan;155(1):89-94. doi: 10.1016/j.cbpc.2011.05.005. Epub 2011 May 18. Characterization of telomeres and telomerase expression in Xiphophorus. (PubMed Abstract)

Shen Y, Catchen J, Garcia T, Amores A, Beldorth I, Wagner J, Zhang Z, Postlethwait J, Warren W, Schartl M, Walter RB. Comp Biochem Physiol C Toxicol Pharmacol. 2012 Jan;155(1):102-8. doi: 10.1016/j.cbpc.2011.03.012. Epub 2011 Apr 3. Identification of transcriptome SNPs between Xiphophorus lines and species for assessing allele specific gene expression within F₁ interspecies hybrids. (PubMed Abstract)

Yang H, Savage MG, Hazlewood L, Walter RB, Tiersch TR. Comp Biochem Physiol C Toxicol Pharmacol. 2012 Jan;155(1):55-63. doi: 10.1016/j.cbpc.2011.04.008. Epub 2011 May 15. Offspring production with cryopreserved sperm from a live-bearing fish Xiphophorus maculatus and implications for female fecundity. (PubMed Abstract)

Fieber LA, Tanguay RL, Walter RB, Williams DE. Comp Biochem Physiol C Toxicol Pharmacol. 2012 Jan;155(1):9-10. doi: 10.1016/j.cbpc.2011.06.010. Epub 2011 Jun 28. Aquatic animal models of human disease: selected papers from the 5th conference. No abstract available.


Shen, Y., Garcia, T., and R. B. Walter. (2011) De novo Transcriptome Assembly and Gene Expression Analysis using RNA-Seq from Organisms Lacking Substantial Genomic Resources. In: Systems and Computational Biology - Molecular and Cellular Experimental Systems, Ning-Sun Yang (ed.), ISBN  978-953-307-280-7, INTECH publications. Janeza Trdine 9, 51000, Rijeka, Croatia, 24 pages. This paper reached over 2,000 downloads in 04-10-13

Cuevas-Uribe R, Yang H, Daly J, Savage MG, Walter RB, Tiersch TR. Zebrafish. 2011 Dec;8(4):167-79. doi: 10.1089/zeb.2011.0704. Epub 2011 Sep 1. Production of F₁ offspring with vitrified sperm from a live-bearing fish, the green swordtail Xiphophorus hellerii. (PubMed Abstract)

Zhang Z, Wang Y, Wang S, Liu J, Warren W, Mitreva M, Walter RB. PLoS One. 2011 Apr 5;6(4):e18379. doi: 10.1371/journal.pone.0018379. Transcriptome analysis of female and male Xiphophorus maculatus Jp 163 A. (PubMed Abstract)


Laisney JA, Braasch I, Walter RB, Meierjohann S, Schartl M. BMC Evol Biol. 2010 Jan 27;10:27. doi: 10.1186/1471-2148-10-27.  Lineage-specific co-evolution of the Egf receptor/ligand signaling system. (PubMed Abstract)

Wise JP Sr, Goodale BC, Wise SS, Craig GA, Pongan AF, Walter RB, Thompson WD, Ng AK, Aboueissa AM, Mitani H, Spalding MJ, Mason MD. Aquat Toxicol. 2010 Apr 1;97(1):34-41. doi: 10.1016/j.aquatox.2009.11.016. Epub 2009 Dec 2. "Silver nanospheres are cytotoxic and genotoxic to fish cells." (PubMed Abstract)

Selected earlier publications

Walter, R.B., Timmins, G. S., Tilton, S. C., Orner, G. O., Benninghoff, A. D., Bailey, G.S., and D.E. Williams. (2008) "Carcinogenesis Models: Focus on Xiphophorus and Rainbow Trout". In: Oceans and Human Health - Risks and Remedies from the Sea, Chapter 32, pp 585-612. Pat Walsh Sharon Smith, Lore Fleming, Helena Solo-Gabriele and William Gerwick (Eds.), ISBN: 978-0-12-372584-4, Elsevier - Academic Press, San Diego, CA 92101-4495.

 Recent Grants (back to top)

Active Grants

R24-OD-011120 - NIH-ORIP (Renewal of RR-024790)    Walter, R. B., (PI)    08/01/11 - 07/31/16

“Enhanced development of the Xiphophorus Model System”. The Specific Aims include: (1) maintenance and enhancement the Xiphophorus Genetic Stock Center to provide the research community animals and resources from genetically-managed lines according to the specifications of each investigator. (2) To sequence and annotate genomes of X. helleri, X. couchianus, and X. montezumae and (3) to initiate a sperm repository for XGSC stocks.

R24-OD-011199 - NIH-ORIP, R24    Walter, R. B. (Co-PI)    09/15/11 - 08/31/15

“Advancing the Scientific Potential of Transcriptomics in Aquatic Models”, The Specific Aims are centered around developing a set of protocols and best practices for transcriptome analyses of aquatic non-model organisms to facilitate the planning and analysis of such studies by external scientists. William Cresko, (P.I.) and John Postlethwait (Co-PI), University of Oregon.

R24-OD-011120-05S1 - NIH-ORIP    Walter, R. B. (PI)    09/01/12 - 08/31/14

Supplement to Promote Diversity in Health-Related Research. “Enhanced Development of the Xiphophorus Model System (2 years).

R25-GM-107759 – NIGMS    Bridges to Baccalaureate    Walter, R. B. (PI)    09-01-13 - 08-31-19

“Bridges to Biomedicine”, Texas State University will partner with two of the Alamo Community Colleges; San Antonio Community College (SAC) and Northwest Vista Community College (NVC), to establish a program focused on strengthening student transfer relationships and increasing success of under-represented minority (URM) students in the biomedical sciences upon transfer to the baccalaureate institution. R. B. Walter, P.I. (TxState), S. Volk de Garcia, Prog. Coord. (TxState), K. Madappat (SAC) and P. Nair (NVC), Co-P.I.’s.

R25-GM-102783 - NIGMS    Bridges to Doctorate    Walter, R. B. (PI)    09-01-13 - 08-31-19

“South Texas Doctoral Bridge Program” is a collaboration between the Univ. of Texas Health Science Center San Antonio (UTHSCSA) and Texas State University in San Marcos (TxState). The Program is designed to provide a combination of mentoring and student development activities as well as rigorous research training during a thesis-based M.S. degree in Biochemistry that will ensure Bridge Scholars completing the program will be prepared for graduate studies in the highest quality doctoral programs in biomedical science nationwide. B. Oyajobi, P.I. (UTHSCSA), N. Blake (UTHSCSA), and R. Booth (TxState) P.I.’s,

R24-OD-011120 - NIH-ORIP    Walter R. B. (PI)    09/01/13 - 08/31/14

Administrative Supplement to “Enhanced Development of the Xiphophorus Model System” entitled “Light Induced Gene Expression” (1 year).

Completed Research Support Within the Last Three Years

Japan Society for the Promotion of Science,    Young Researcher Overseas Program     06/01/12-05-31-14

This grant supports one Japanese Postdoctoral Associate (Dr. Ryo Nozu) to visit the Walter laboratory at TSU to perform “Transcriptome Expression Analyses of Sexual Reversal in the Wrasse.” Kyoshi Naruse (PI), Natl. Inst. Basic Biology, Japan), and R.B. Walter (Co-PI), TSU.

NSF-1049208 - NSF    RAPID Award    Walter, R.B. (Co-PI)    09/01/10-08/31/12

“Collaborative Research: Genetic Impact of the Deepwater Horizon Oil Release”. This award is aimed at assessing the genetic impact of oil exposure on Fundulus populations along the Louisiana coast. D. Crawford (PI), U. Miami, and A. Whitehead (Co-PI), LSU.

R24-RR024790 – NIH-NCRR    Walter, R.B., (PI)    10/31/09 - 05/31/12

“ARRA Supplement (Translational) to R24-RR024790”. The rationale for this award is the impact of establishing functional genomic capabilities for three Xiphophorus species used in tumor models.

R24-RR024790 – NIH-NCRR    Walter, R.B. (PI)    06/30/08 - 05/31/12

“Enhanced development of the Xiphophorus Model System”. Aims include preservation and enhancement of the Xiphophorus Genetic Stock Center to provide the research community with animals, materials, and tools from genetically-managed fish lines. Also, to continue development of cryopreservation technology for Xiphophorus.

NA06NOS4260118 - NOAA    National Ocean Program    Walter, R.B. (PI)    09/01/08- 08/31/10

"The Aquatic Research Consortium: Proteomic and Organismal Reponses of Aquatic Organisms to Hypoxia and Toxic Metals". William Hawkins (USM-GCML), program coordinator; PI’s – M. Brouwer (USM-GCML) and R.B. Walter (TSU)