Faculty

Andrew Alverson

Andrew Alverson

Assistant Professor

J. William Fulbright College of Arts & Sciences

(BISC)-Biological Sciences

Phone: 479-575-7975

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Most of the lab's current research falls into one of the following four areas:

1.   Genomic Insights Into the Origin of Diatoms 

With some 200,000 species, diatoms are probably the most species-rich lineage of microbial eukaryotes. In sharp contrast, the sister group to diatoms (the Bolidophyceae) includes fewer than 20 species. Comparing bolidophyte genomes to those of early diverging diatoms will allow us to pinpoint the key genomic changes that took place in the common ancestor of all diatoms. We're sequencing the genomes of diatom species that bracket the earliest splits in the phylogeny and comparing them to the genomes of closely related outgroup species. These data will provide key insights into the origins of novel diatom traits, including those that may have facilitated their extraordinary phylogenetic and ecological diversification.

2.   The Rates, Patterns, and Roles of Cross-Kingdom HGT in Diatom Evolution

One of the biggest surprises to come out of first diatom genome projects was the presence of hundreds of genes acquired by horizontal transfer from Bacteria and Achaea. The genome of one species contains nearly 800 genes of recent bacterial origin, whereas only half of these genes were found in the other species. This points to a dynamic history of foreign gene gain and/or loss over the course of diatom evolution, a pattern that is best resolved against the backdrop of a strongly supported organismal phylogeny. We're augmenting efforts to reconstruct the diatom phylogeny using hundreds of low-copy nuclear markers, sequencing transcriptomes of >200 additional diatoms, and developing a phylogenetically based analytical pipeline for de novo detection of foreign genes. We'll then formally reconstruct the history of foreign gene gains across the phylogeny to determine whether foreign sequence acquisitions coincide with major diversification events or the origins of novel traits.

3.   The Evolutionary Transition Between Marine and Fresh Waters

Freshwater colonizations are landmark events in diatom evolution, having led to the origins of perhaps tens of thousands of species. A primary goal of this research is to understand the morphological, physiological, and genetic adaptations that have allowed diatoms to diversify into freshwater environments, which present numerous obstacles to marine colonists. We're using a blend of phylogenetic, experimental, and genomic approaches to understand how diatoms have successfully, and repeatedly, conquered "the salinity barrier". This project is focused primarily on Thalassiosirales, a lineage that presents an ideal model system for several reasons: (1) most species are easily cultured; (2) the lineage includes the model species, Cyclotella nana, which offers excellent genomic resources, and; (3) there is a strongly supported phylogenetic hypothesis, laying out a rich and well-resolved historical pattern of marine–freshwater transitions. This history includes numerous successful freshwater colonizations, so nature has played out this experiment multiple times. Our goal is to determine whether these natural experiments played out in the same, or different, ways.

  • Evolutionary Biology (fall)
  • Practical Programming for Biologists (spring)

Ph.D. The University of Texas at Austin, 2006

M.S. Iowa State University, 2000

Ruck EC, Nakov T, Alverson AJ, Theriot EC. 2016. Phylogeny, ecology, morphological evolution, and reclassification of the diatom orders Surirellales and Rhopalodiales. Mol Phylogenet Evol 103:155-171

Park JS, Alverson AJ, Lee JH. 2016. A phylogenetic re-definition of the diatom genus Bacterosira (Thalassiosirales, Bacillariophyta), with the transfer of Thalassiosira constricta based on morphological and molecular characters. Phytotaxa 245(1):1-16

Nakov T, Guillory WX, Julius ML, Theriot EC, Alverson AJ. 2015. Towards a phylogenetic classification of species belonging to the diatom genus Cyclotella (Bacillariophyceae): Transfer of species formerly placed in Puncticulata, Handmannia, Pliocaenicus and Cyclotella to the genus Lindavia. Phytotaxa 217(3):249-264

Kessenich CR, Ruck EC, Schurko AM, Wickett NJ, Alverson AJ. 2014. Transcriptomic insights into the life history of bolidophytes, the sister lineage to diatoms J Phycol. 50(6):977–983

Ruck EC, Nakov T, Jansen RK, Theriot EC, Alverson AJ. 2014. Serial gene losses and foreign DNA underlie size and sequence variation in the plastid genomes of diatoms. Genome Biol. Evol. 63(3):644-654 PMC3971590

Alverson AJ. 2014. Timing marine–freshwater transitions in the diatom order Thalassiosirales. Paleobiology 40(1):91-101

Nakov T, Theriot EC, Alverson AJ. 2014. Using phylogeny to model cell size evolution in marine and freshwater diatoms. Limnol. Oceanogr. 59(1):79-86

Rice DW, Alverson AJ, Richardson AO, Young GJ, Sanchez-Puerta MV, Munzinger J, Barry K, Boore JL, Zhang Y, dePamphilis CW, Knox EB, Palmer JD. 2013. Horizontal transfer of entire genomes via mitochondrial fusion in the angiosperm Amborella. Science 342(6165):1468-73

Gutu A, Nesbit AD, Alverson AJ, Palmer JD, Kehoe DM. 2013. Unique role for translation initiation factor 3 in the light color regulation of photosynthetic gene expression. Proc. Natl. Acad. Sci. U.S.A. 110(40):16253-8

Sloan DB, Alverson AJ, Chuckalovcak JP, Wu M, McCauley DE, Palmer JD, Taylor DR. 2012. Rapid evolution of enormous, multichromosomal genomes in flowering plant mitochondria with exceptionally high mutation rates. PLoS Biol. 10(1):e1001241

Alverson AJ, Rice DW, Dickinson S, Barry K, Palmer JD. 2011. Origins and recombination of the bacterial-sized multichromosomal mitochondrial genome of cucumber. Plant Cell 23(7):2499-513

Alverson AJ, Beszteri B, Julius ML, Theriot EC. 2011. The model marine diatom Thalassiosira pseudonana likely descended from a freshwater ancestor in the genus Cyclotella. BMC Evol. Biol. 11:125

Alverson AJ, Wei X, Rice DW, Stern DB, Barry K, Palmer JD. 2010. Insights into the evolution of mitochondrial genome size from complete sequences of Citrullus lanatus and Cucurbita pepo (Cucurbitaceae). Mol. Biol. Evol. 27(6):1436-48

Alverson AJ. 2008. Molecular systematics and the diatom species. Protist 159(3):339-53

Alverson AJ, Jansen RK, Theriot EC. 2007. Bridging the Rubicon: Phylogenetic analysis reveals repeated colonizations of marine and fresh waters by thalassiosiroid diatoms. Mol. Phylogenet. Evol. 45(1):193-210