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J. Spencer Johnston

Johnston, J. Spencer
J. Spencer Johnston
Professor of Genetics/Entomology, Member of Genetics Faculty, Member of Graduate Faculty
Undergraduate Education
University of Washington, Seattle, Washington, Zoology, B.S., 1967
Graduate Education
University of Texas, Austin, Texas, Drosophila genetics, 1972-1975, NIH Fellow
University of Arizona, Tucson, Arizona, Genetics, Ph.D., 1972 (Advisor: W. B. Heed)


  • Sept. ‘97 – Present: Professor, Dept. Entomol., Texas A&M University, College Station, TX
  • 1989 – Present: Dtr. Flow Cytometry, Center for Biosystematics and Biodiversity, TAMU
  • Sept. ‘86 – Aug. ’97: Assoc. Prof., Dept. Entomology, Texas A&M University, Col. Sta., TX
  • Jan. ‘80 – Aug. ’86: Assoc. Prof., Dept. Plant Science, Texas A&M University, Col. Sta., TX
  • Sept. ‘75 – Dec. ’79: Asst. Prof., Dept. Biology, Baylor University, Waco, TX
  • June ‘67 – July ’68: Systems Analyst, Boeing Company, Seattle, WA

Teaching Activities

My teaching involves undergraduate courses in forensic genetics (FIVS 308), population and ecological genetics (GENE 412 and 412H) and genetics seminar (GENE 481). The FIVS course covers the application of genetics in forensic science. GENE 412 covers the basic principles of population genetics, the impact of DNA sequence data on population studies, and presents population genetics through examples. GENE 481 involves student attendance at the regularly scheduled seminars of the TAMU faculty of genetics plus graded written summaries of selected seminars.

Research Interests:

Genomics: My laboratory is interested in the diversity of Arthropod genomes, and contributes to efforts to describe and annotate the complete genomic sequence of a wide variety of Arthropods, including the honey bee, mosquito, Antarctic midge, bedbug, body louse, varroa mite and others. A long term goal of my laboratory is to understand the forces that shape genomic diversity, between cells in an individual, between single individuals and between populations of a species, and among species.

Population level studies: We have been assessing the genetic impact of the arrival of the Africanized form of the honey bee, Apis mellifera scutellata. We have extensive collections of feral bees from colonies in South Texas and bait hive bees in Mexico spanning the period 1990 to 2003, which is three years prior, the time during, and the successive years after the invasion of the Africanized bee. We score mtDNA mitotypes and nuclear microsatellite loci and single nucleotide polymorphisms (SNPs). The data shows that the African and European mitochondrial lineages coexist, while the nuclear genome is a mixture of the genomes of both lineages. Using the same genetic approach, we are studying the population structure of the honey bee in Western Europe. This is an area of diversity, and endemism, that contains a significant portion of the genetic variation needed to enhance honey bee survival and productivity. We have studies on a wide variety of Arthropods, including, the walking stick, Drosophila species, a several species of beetles.

Genome size estimation: Our laboratory uses flow cytometry to provide genome size estimates for a variety of insects, plants and other animals. We measure genome size to correct questionable values produced by other methods, and provide new values for researches who need to know genome size to develop gene libraries. We uniquely determine genome size in groups of closely related organisms in an effort to better understand the process of genome size evolution.

Grants Received (Last 5 years)

  • Development of an integrated cyto-molecular map for the honeybee. USDA-NRI Competitive Grant. $52,000 (2003-2004), (J. S. Johnston).
  • A BAC library for genomic sequencing of the honeybee. The American Beekeeping Federation, the College of Agriculture and Life Sciences and the Office of University Research, Texas A&M University, College Station, TX., $40,000 (2001), (J. S. Johnston).
  • Population structure of the red imported fire ant, Solenopsis invicta Buren. The Texas Fireant Initiative. $150,000, (2000-2002), (J. S. Johnston).
  • Ploidy and genetic sterility in the red imported fire ant, Solenopsis invicta Buren. The Texas Fireant Initiative. $150,000, (1997-1999), (J. S. Johnston).

Publications (Last 5 years)

Full List of Publications (PDF)

Benoit, J. B. Z. N. Adelman, et al. (bedbug sequencing consortium). 2015. Unique features of a global human ectoparasite identified through sequencing of the bed bug genome. Nature Communications (in Press).

Chávez-Galarza, J., D. Henriques, J.S. Johnston, M. Carneiro, J. Rufino, J.C. Patton and M.A. Pinto. 2015. Revisiting the Iberian honey bee (Apis mellifera iberiensis) contact zone: maternal and genome-wide nuclear variations provide support for secondary contact from historical refugia. Mol. Ecol. 24: 2973–2992. DOI: 10.1111/mec.13223

Rangel, J., K. Strauss, K. Seedorf, CE Hjelmen, JS Johnston. 2015. Endopolyploidy changes with age-related polyethism in the honey bee, Apis mellifera.” PLoS One 04/2015;10(4):e0122208. DOI:10.1371/journal.pone.0122208. 3.53 Impact Factor

Muñoz I., D. Henriques, J. Chávez-Galarza, J. Rufino, J. S. Johnston, M. A. Pinto. 2015. Reduced SNP panels for genetic identification and introgression analysis in the dark honey bee (Apis mellifera mellifera). PLoS One 10(4) e0124365. doi: 10.1371/journal.pone.0124365.

Cheng W., Lei J., Fox C., Johnston J.S., Zhu-Salzman K. 2015. Comparison of life history and genetic properties of cowpea bruchid strains and their response to hypoxia. J. Insect Phys. 75: 5-11. DOI information: 10.1016/j.jinsphys.2015.02.008

Arnqvist Goren, Ahmed Sayadi, Elina Immonen, Cosima Hotzy, Daniel Rankin, Midori Tuda, Carl E. Hjelmen, J. Spencer Johnston. 2015. Correlated evolution of genome size and reproductive fitness in seed beetles. Royal Society Series B (in Press).

Kapheim KM, H. Pan, et al. 2015. Genomic signatures of evolutionary transitions from solitary to group living. Science 348 (6239):1139-1143. DOI: 10.1126/science.aaa4788.

Ellis L.L., Huang W., Quinn A.M., Ahuja A., Alfrejd B., Johnston, J.S., Tarone A. 2014. Intrapopulation genome size variation in D. melanogaster reflects life history variation and plasticity. PLoS Genet. 10(7): e1004522. doi:10.1371/journal.pgen.1004522

Tarone, A.M., J.K. Tomberlin, J.R. Wallace, M.E. Benbow, R. Mohr, Edward B. Mondor, J.S. Johnston & S.L. VanLaerhoven. 2014. Reply: A Correspondence from a Maturing Discipline. Jn. Med. Ent. 51(3):490-492.

Soria-Carrasca, V., Z. Gompert, A. A. Comeault, T. E. Farkas, T. L. Parchman, J. S. Johnson, C. A. Buerkle, J. L. Feder, J. Bast, T. Schwander, S. P. Egan, B. J. Crespi, P. Nosil. 2014. Stick Insect genomes reveal natural selection’s role in parallel speciation. Science 334(6185):738-742.

Pinto, M.A., D. Henriques, J. Chavez-Galarza, P. Kryer, L. Garnery, R. Van Der Zee, B. Dahle, G. Soland-Recheweg, J.S. Johnston. 2014. Genetic integrity of the dark European honey bee (Apis mellifera mellifera) from protected populations: a genome-wide assessment using SNPs and mtDNA sequence data. Jn. Apic. Rch. 53(2):269-278. doi: 10.3896/IBRA.

Pimsler, M. L., T. Pape, J. S. Johnston, R. A. Wharton, J. J. Parrott, D. Restuccia1, M. R. Sanford, J. K. Tomberlin, and A. M. Tarone. 2014. Structural and genetic investigation of the egg and first-instar larva of an egg-laying population of Blaesoxipha plinthopyga (Diptera: Sarcophagidae), a species of forensic importance. Jn. of Med. Ent. 51(6):1-13. DOI: http://dx.doi.org/10.1603/ME14029

Kelley, J.L., J.T. Peyton, A-S Fiston-Lavier, N.M. Teets, M.C. Yee, J.S. Johnston, C.D. Bustamante, R.E. Lee, Jr. & D.L. Denlinger. 2014. Compact genome of the Antarctic midge is likely an adaptation to an extreme environment. Nature Communications 5:4611.

Boussau, B., Z. Walton, J. A. Delgado, F. Collantes, L. Beani, I. J. Stewart, S. A. Cameron, J. B. Whitfield, J. S. Johnston, P. W. H. Holland, D. Bachtrog, J. Kathirithamby, J. P. Huelsenbeck. 2014. Strepsiptera, phylogenomics and the long branch attraction problem. PLoS ONE 9(10):e107709.

Portnoy, D. S., C. M. Hollenbeck, J. S. Johnston, H. M. Casman, J. R. Gold. 2014. Parthenogenesis in a reef whitetip shark Triaenodon obesus involves a reduction in ploidy. Jn. Fish Biol. doi: 10.1111/jfb.12415.

Huang, W., A. Massouras, et al. 2014. Natural variation in genome architecture among 205 Drosophila melanogaster Genetic Reference Panel lines . Genome Res. (Impact Factor: 14.4). 04/2014; doi:10.1101/gr.171546.113.

Scholes, D.R., A.V. Suarez, A.A. Smith J.S. Johnston, K. N. Paige. 2014. Tissue-specific patterns of endopolyploidy in the giant ant Dinoponera australis. J. Hymenoptera Research. 37: 113-126

Chávez-Galarza, J., Henriques, D., Johnston, J.S., Azevedo, J., Patton, J.C., Muñoz, I., De la Rúa, P., Pinto, M.A. 2013. Signatures of selection in the Iberian honey bee (Apis mellifera iberiensis) revealed by a genome scan analysis of single nucleotide polymorphisms. Mol. Ecol. 22(23):5890-907 DOI. 10.1111/mec.12537.

Johnston, J.S., Schoener, M., & McMahon, D.P. 2013. DNA underreplication in the majority of nuclei in the Drosophila melanogaster thorax: evidence from Suur and flow cytometry. Journal of Molecular Biology Research, 3(1), 47-54. 2.5

Picard, C.J., J.S. Johnston and A.M. Tarone. 2013. Increasing precision in development-based postmortem interval estimates: what’s sex got to do with it? Journal of Medical Entomology 50(2): 425-431.

Jacobson, A.L., J.S. Johnston, D. Rotenberg, A.E. Whitfield, W. Booth, E.L. Vargo and G.G. Kennedy. 2012. Genome size and ploidy of Thysanoptera. Insect Molecular Biology 1165:12-17. doi: 10.1111/j.1365-2583.2012.01165 3.0

Kathirithamby, J., G. K. Lechner, D.P. McMahon, A.L. Bryson, and J.S. Johnston. 2012. A free ride and lunch: Stylopization in the solitary hunting wasp, Ammophila fernaldi Murry and A. pictipennis (Walsh) (Hymenoptera: Sphecidae) by Paraxenos lugubris Pierce (Strepsiptera). Proc. Entomol. Soc. Wash. 114: 464-475.

Chávez-Galarza, J., Henriques, D., Johnston, J. S., Azevedo, J., Muñoz, I., De la Rúa, P., Patton, J. C., Costa, F., Pinto, M. A. 2012. Detection of loci under selection in Apis mellifera iberiensis as compared with two frequentist methods. In IV Jornadas Nacionais de Genética e Biotecnologia. Vila Real: UTAD. http://hdl.handle.net/10198/6792

Picard, C.J., J.S. Johnston and A.M. Tarone. 2012. Genome sizes of forensically relevant Diptera. Journal of Medical Entomology 49:192-197.

Hanrahan, S.J., Johnston, J.S. 2011. New genome size estimates of 134 species of arthropods. Chromosome Research 19:809-23.

Chávez-Galarza, J., J.S. Johnston, J. Azevedo, I. Muñoz, P. De la Rúa, J. C. Patton, and M.A. Pinto. 2011. Signatures of selection in the Iberian honey bee: a genome wide approach using single nucleotide polymorphisms (SNPs). Apimondia. http://hdl.handle.net/10198/6790

Gokhman, V.E., J.S. Johnston, C. Small, R. Rajwani, S. Hanrahan, S. Govind. 2011. Genomic and karyotypic variation in Drosophila parasitoids (Hymenoptera: Cynipoidea: Figitidae). Comparative Cytogenetics 5:211-221. HDY-11-OR0058.

Sirviö, A., J.S. Johnston, T. Wenseleers, and P. Pamilo. 2011. A high recombination rate in eusocial Hymenoptera: evidence from the common wasp Vespula vulgaris. BMC Genetics 2011, 12:95doi:10.1186/1471-2156-12-95.

Baxter S.W., J.W. Davey, J.S. Johnston, A.M. Shelton, D.G. Heckel, C.D. Jiggins, and M.L. Baxter. 2011. Linkage mapping and comparative genomics using next-generation RAD sequencing of a non-model organism. PLoS ONE 6(4): e19315. doi:10.1371/journal.pone.0019315

Hare, E.E., and J.S. Johnston. 2011. Genome size determination using flow cytometry of propidium iodide-stained nuclei. Molecular Methods for Evolutionary Genetics, 3-12.

Cornman, R.S., M.C. Schatz, J.S. Johnston, Y.P. Chen, J. Pettis, G. Hunt, L. Bourgeois, C.G. Elsik, D. Anderson, C.M. Grozinger, and J.D. Evans. 2010. Genomic survey of the ectoparasitic mite Varroa destructor, a major pest of the honey bee Apis mellifera. BMC Genomics 11:602.

Weiss, T.J., J.S. Johnston, K. Fujisawa, S. Okada, T.P. Devarenne. 2011. Genome size and phylogenetic analysis of the A and L races of Botryococcus braunii. J. Applied Phycology 23: 833-839. DOI: 1007/s10811-010-9586-7.

Kirkness, E.F., B.J. Haas, et al. 2010. Genome sequences of the human body louse and its primary endosymbiont provide insights into the permanent parasitic lifestyle. Proceedings of the National Academy of Science USA 107: 12168-12173.

Weiss, T. J., J. S. Johnston, K. Fujisawa, K. Sumimoto, S. Okada, J. Chappell, T. P. Devarenne. 2010. Phylogenetic placement, genome size, and GC content of the liquid-hydrogen-producing green microalga Botrycoccus braunii strain Berkeley (Showa) (Chlorophyta). J. Phycology 46:534-540.

Grants Received (Last 5 years)

  • Genome size estimation service for the i5K project: $12,500 by contracts with participants.
  • Preliminary genomic sequences for the phylogenetic study of insects in the order Neuroptera (Insecta) WSGI (TAMU) incentive grant. John Oswald (PI); Spencer Johnston (Co-PI) April 2011- March 31, 2012. $10,000
  • Patterns and processes of (neutral and adaptive) variation in the honey bee (Apis mellifera iberiensis) hybrid zone of the Iberian Peninsula: a population genetics approach integrating population genomics and landscape genetics. Ministry of technology and Science, Portugal. ($173,168 EU) (MA Pinto PI; JS Johnston Co-PI). 2010-2015.

Honors and Awards

  • 1992 Outstanding Undergraduate Genetics Professor
  • 1996 Outstanding Undergraduate Genetics Professor
  • 1998 C-value (plant Genome size) Workshop, Jodrell Labs, RBGKew, UK
  • 1999 Visiting Fellow, Department of Zoology, Oxford University
  • 2000 Comparative Insect Genomics Workshop, Washington, D.C.
  • 2001 The honey bee genome white paper workshop, BHGSC, Houston
  • 2002 NCBI Honey bee genomics workshop, Bethesda, MA
  • 2003 Honey bee genomics workshop, Int. Cong. Genet., Melbourne, Australia
  • 2003 C-value (plant Genome size) Workshop, Jodrell Labs, RBGKew, UK
  • 2003 Visiting Fellow, St. Hugh’s College, Oxford University
  • 2004 Invited speaker International Congress of Entomology, Brisbane, Aus.
  • 2006 Bennett, Price & Johnston (2003) identified by Thompson ISIR as most cited in the area of ‘Recent Genome Size Variation’
  • 2006 Named “Author of the Year” by Jn. Insect Mol. Biol.
  • 2006 Four papers in Ann. Botany listed among 10 most cited in the journal history.
  • 2006 Paper in Nature chosen for the cover.
  • 2007 Paper in Science chosen for the cover.
  • 2008 Invited speaker. Insect genomics workshop. Plant & Animal Genome
  • 2010 Invited speaker. Genome size evolution Workshop – Univ. of Guelf
  • 2011 TAMU delegate. Federal Demonstration Partnership, Washington DC
  • 2012 Invited speaker. Arthropod Genome Workshop – Kansas City, Mo.
  • 2014 Paper in Science chosen for the cover.