The Gile Lab

Protist diversity, evolution, & symbiosis
Arizona State University - Tempe, AZ USA


What are Protists?

Animals, plants, and fungi, and protists together make up the eukaryotes. While plants, animals and fungi are each ancient lineages that independently evolved multicellularity, protists are a diverse assemblage of lineages that are separated from our common ancestor by about 1.5 billion years of evolution. Protist diversity is deep, with differences in things like mitosis, mitochondrial genomes and morphology, and photosynthetic capability that are nearly identical across animals, plants, or fungi. Many or perhaps most protists live in symbiosis with bacteria or other eukaryotes, and symbiosis has played a pivotal role in eukaryotic evolution by providing us with mitochondria and plastids.


One of the most ancient and important symbioses of all is the establishment of plastids. Beginning over 1 billion years ago, when a host cell failed to digest its cyanobacterial food, an association between two single celled organisms gradually became a new, single organism. In the Gile lab we study the gene transfer and protein targeting that enabled the transition from symbiosis to new organism. We also study the loss of photosynthesis, which has happened many times in various lineages without loss of the plastid itself. Despite the importance of photosynthesis to life on earth, we do not fully understand how many times endosymbiosis has led to a new photosynthetic eukaryotic lineage, yet another topic of research in the Gile lab.


Another fascinating symbiosis occurs between certain families of termites and the protists that live in their hindguts. The termites rely on these protists to help them digest wood, and in return, the protists have a safe microcosm where they have flourished, becoming larger and morphologically more complex over about 150 million years of coevolution. We apply microscopy and molecular and computational techniques to study these protists, with particular interests in evolutionary rates, speciation, phylogeny, and morphological convergence. Much of this work is geared towards reconstructing the coevolutionary history of termites and protists.


Azolla is a floating water fern that keeps a nitrogen-fixing cyanobacterial symbiont related to Nostoc in specialized cavities within its leaves. Although neither partner is a protist, there are interesting parallels between this symbiosis and what we imagine the early stages of plastid establishment to be like: the cyanobacterial symbiont genome is eroding and it can no longer survive outside the host plant. In collaboration with Kathleen Pryer's lab at Duke University, we will be investigating the molecular basis of this symbiosis by looking at Azolla genome sequences.


Gillian Gile, PhD
  • Assistant Professor
Francesca de Martini, PhD
  • Senior Research Specialist
Stephen Taerum, PhD
  • Postdoctoral Fellow
Gregory Gavelis, PhD
  • Postdoctoral Fellow
Trevor Merrell
  • Undergraduate Researcher
Katalina Peterson
  • Undergraduate Researcher
Daniel Jasso-Selles
  • Undergraduate Researcher
Mikaela Garcia
  • Undergraduate Researcher


The Gile lab has openings for graduate students and postdocs to work on termite hindgut protists, plastid evolution, or the Azolla-Nostoc symbiosis. If you are interested in any of these topics, or have other ideas related to protists or symbiosis, please contact Dr. Gile for more information.


Gile GH, Moog D, Slamovits CH, Maier U-G, Archibald JM. 2015. Dual organellar targeting of aminoacyl-tRNA synthetases in diatoms and cryptophytes. Genome Biology and Evolution 7:1728-1742.

Gile GH, James ER, Okamoto N, Carpenter KJ, Scheffrahn RH, Keeling PJ. 2015. Molecular evidence for the polyphyly of Macrotrichomonas (Parabasalia: Cristamonadea) and a proposal for Macrotrichomonoides n. gen. Journal of Eukaryotic Microbiology 62:494-504.

Tai V, Gile GH, Pan J, James ER, Carpenter KJ, Scheffrahn RH, Keeling PJ. 2015. The phylogenetic position of Kofoidia loriculata (Parabasalia) and its implications for the evolution of the Cristamonadea. Journal of Eukaryotic Microbiology 62:255-259.

Gile GH and Slamovits CH. 2014. Transcriptomic analysis reveals evidence for a cryptic plastid in the colpodellid Voromonas pontica, a close relative of chromerids and apicomplexan parasites. PLoS ONE 9:e96258.

Gile GH†, Carpenter KJ†, James ER, Scheffrahn RH, and Keeling PJ. 2013. Morphology and molecular phylogeny of Staurojoenina mulleri sp. nov. (Trichonymphida, Parabasalia) from the hindgut of the kalotermitid Neotermes jouteli. Journal of Eukaryotic Microbiology 60:203-213. †Contributed equally.

Curtis BA, Tanifuji G, Burki F, Gruber A, Irimia M, Maruyama S, Arias MC, Ball SG, Gile GH, Hirakawa Y, Hopkins JF, Kuo A, Rensing SA, Schmutz J, Symeonidi A, Elias M, Eveleigh RJM, Herman EK, Klute MJ, Nakayama T, Oborník M, Reyes-Prieto A, Armbrust EV, Aves SJ, Beiko RG, Coutinho P, Dacks JB, Durnford DG, Fast NM, Green BR, Grisdale CJ, Hempel F, Henrissat B, Höppner MP, Ishida K-I, Kim E, Kořený L, Kroth PG, Liu Y, Malik S-B, Maier U-G, McRose D, Mock T, Neilson JAD, Onodera NT, Poole AM, Pritham EJ, Richards TA, Rocap G, Roy SW, Sarai C, Schaack S, Shirato S, Slamovits CH, Spencer DF, Suzuki S, Worden AZ, Zauner S, Barry K, Bell C, Bharti AK, Crow JA, Grimwood J, Kramer R, Lindquist E, Lucas S, Salamov S, McFadden GI, Lane CE, Keeling PJ, Gray MW, Grigoriev IV, Archibald JM. 2012. Algal genomes reveal evolutionary mosaicism and the fate of nucleomorphs. Nature 492:59-65.

Pawlowski J, Audic S, Adl S, Bass D, Belbahri L, Berney C, Bowser SS, Čepička I, Decelle J, Dunthorn M, Fiore-Donno A-M, Gile GH, Holzmann M, Jahn R, Jirků M, Keeling PJ, Kostka M, Kudryavtsev A, Lara E, Lukeš J, Mann DG, Mitchell EAD, Nitsche F, Romeralo M, Saunders GW, Simpson AGB, Smirnov AV, Spouge JL, Stern RF, Stoeck T, Zimmermann J, Schindel D, de Vargas C. 2012. CBOL Protist Working Group: Barcoding eukaryotic richness beyond the animal, plant and fungal kingdoms. PLoS Biology 10:e1001419.

Gile GH and Slamovits CH. 2012. Phylogenetic position of Lophomonas striata Bütschli (Parabasalia) from the hindgut of the cockroach Periplaneta americana. Protist 163:274-283.

Saldarriaga J†, Gile GH†, James ER, Horák A, Scheffrahn RH, and Keeling PJ. 2011. Morphology and molecular phylogeny of Pseudotrichonympha hertwigi and Pseudotrichonympha paulistana (Trichonymphea, Parabasalia) from neotropical rhinotermitids. Journal of Eukaryotic Microbiology 58:487-496. †Contributed equally.

Gile GH, James ER, Scheffrahn RH, Carpenter KJ, and Keeling PJ. 2011. Molecular and morphological analysis of the Calonymphidae with a description of Calonympha chia sp. nov., Snyderella kirbyi sp. nov., Snyderella swezyae sp. nov., and Snyderella yamini sp. nov. International Journal of Systematic and Evolutionary Microbiology 61:2547-2558.

Cocquyt E, Gile GH, Leliaert F, Verbruggen H, Keeling PJ, and De Clerck O. 2010. Complex phylogenetic distribution of a non-canonical code in green algae. BMC Evolutionary Biology 10:e327.

Hirakawa Y, Gile GH, Ota S, Keeling PJ, and Ishida K. 2010. Characterization of periplastid compartment targeting signals in chlorarachniophytes. Molecular Biology and Evolution 27:1538-1545.

Gile GH†, Stern RF†, James ER, and Keeling PJ. 2010. DNA barcoding of chlorarachniophytes using nucleomorph ITS sequences. Journal of Phycology 46:743-750. †Contributed equally.

Gile GH, Novis PM, Cragg DS, Zuccarello GC, and Keeling PJ. 2009. The distribution of EF-1α, EFL, and a non-canonical genetic code in the Ulvophyceae: Discrete genetic characters support a consistent phylogenetic framework. Journal of Eukaryotic Microbiology 56:367-372.

Harper JT, Gile GH, James ER, Carpenter KJ, and Keeling PJ. 2009. The inadequacy of morphological concepts for species and genus delineation in microbial eukaryotes: An example from the parabasalian termite symbiont, Coronympha. PLoS ONE 4:e6577.

Gile GH, Faktorová D, Castlejohn CA, Burger G, Lang BF, Farmer MA, Lukeš J, and Keeling PJ. 2009. Distribution and phylogeny of EF-1α and EFL in Euglenozoa suggest an ancient introduction of EFL followed by differential loss. PLoS ONE 4:e51162.

Gile GH and Keeling PJ. 2008. Nucleus-encoded periplastid-targeted EFL in chlorarachniophytes. Molecular Biology and Evolution 25:1967-1977.

Gile GH, Patron NJ, and Keeling PJ. 2006. EFL GTPase in cryptomonads and the distribution of EFL and EF-1α in chromalveolates. Protist 157:435-444.

Gould SB, Sommer MS, Kroth PG, Gile GH, Keeling PJ, and Maier UG. 2006. Nucleus-to-nucleus gene transfer and protein retargeting into a remnant cytoplasm of cryptophytes and diatoms. Molecular Biology and Evolution 23:2413-2422.



Phone: 480-727-4761
Room: LSE 607


Phone: 480-727-4295
Room: LSE 604