About

Jeremiah Hackett is an Associate Professor in the Department of Ecology and Evolutionary Biology at the University of Arizona, a position he has held since 2013. His research interests encompass genome evolution, the evolution of photosynthesis, and the physiology of harmful algae. His work investigates how eukaryotes acquire plastids through endosymbiosis and how this process influences genome evolution via gene transfer. Additionally, he studies the ecology and physiology of harmful algae, utilizing microarrays to analyze global gene expression patterns under various growth conditions. This research aims to identify the factors that lead to harmful algal blooms in the oceans, contributing to a deeper understanding of these phenomena.

Research topics

• Biology
• Evolutionary biology
• Botany
• Genetics
• Cell biology

Selected publications

• Behavioural differences underlie toxicity and predation variation in blooms of <i>Prymnesium parvum</i>

  Ecology Letters · 2023-03-16 · 15 citations

  letterOpen access

  Much of the evolutionary ecology of toxic algal blooms (TABs) remains unclear, including the role of algal toxins in the adaptive 'strategies' of TAB-forming species. Most eukaryotic TABs are caused by mixotrophs that augment autotrophy with organic nutrient sources, including competing algae (intraguild predation). We leverage the standing diversity of TABs formed by the toxic, invasive mixotroph Prymnesium parvum to identify cell-level behaviours involved in toxin-assisted predation using direct observations as well as comparisons between genetically distinct low- and high-toxicity isolates. Our results suggest that P. parvum toxins are primarily delivered at close range and promote subsequent prey capture/consumption. Surprisingly, we find opposite chemotactic preferences for organic (prey-derived) and inorganic nutrients between differentially toxic isolates, respectively, suggesting behavioural integration of toxicity and phagotrophy. Variation in toxicity may, therefore, reflect broader phenotypic integration of key traits that ultimately contribute to the remarkable flexibility, diversity, and success of invasive populations.

  PublisherOA PDFDOI

• Author response for "Behavioural differences underlie toxicity and predation variation in blooms of &lt;i&gt;Prymnesium parvum&lt;/i&gt;"

  2022-08-24

  peer-review
  PublisherDOI

• Additional file 1: Table S1. of Insights into transcriptional changes that accompany organelle sequestration from the stolen nucleus of Mesodinium rubrum

  Figshare · 2015-01-01

  datasetOpen access

  KEGG Categories evaluated under protein and read count tests. 1. Metabolism, 2. Genetic information Processing, 3. Environmental information processing, and 4. Cellular Processes represent broad KEGG categories. Subcategories in bold (1.0â 4.3) were subject to protein count analyses while italicized pathways within these subcateogries were analyzed by the read count method. (XLSX 17 kb)

  PublisherDOI

• Metatranscriptome Analysis of Fig Flowers Provides Insights into Potential Mechanisms for Mutualism Stability and Gall Induction

  PLoS ONE · 2015-06-19 · 26 citations

  articleOpen access

  A striking property of the mutualism between figs and their pollinating wasps is that wasps consistently oviposit in the inner flowers of the fig syconium, which develop into galls that house developing larvae. Wasps typically do not use the outer ring of flowers, which develop into seeds. To better understand differences between gall and seed flowers, we used a metatranscriptomic approach to analyze eukaryotic gene expression within fig flowers at the time of oviposition choice and early gall development. Consistent with the unbeatable seed hypothesis, we found significant differences in gene expression between gall- and seed flowers in receptive syconia prior to oviposition. In particular, transcripts assigned to flavonoids and carbohydrate metabolism were significantly up-regulated in gall flowers relative to seed flowers. In response to oviposition, gall flowers significantly up-regulated the expression of chalcone synthase, which previously has been connected to gall formation in other plants. We propose several genes encoding proteins with signal peptides or associations with venom of other Hymenoptera as candidate genes for gall initiation or growth. This study simultaneously evaluates the gene expression profile of both mutualistic partners in a plant-insect mutualism and provides insight into a possible stability mechanism in the ancient fig-fig wasp association.

  PublisherOA PDFDOI

• Additional file 4: Table S4. of Insights into transcriptional changes that accompany organelle sequestration from the stolen nucleus of Mesodinium rubrum

  Figshare · 2015-01-01

  datasetOpen access

  Description and classification of DESeq log2FC over-expressed genes in KN. Genes of note are in bold with parenthetical notation indicating the pathway to which they belong. (XLSX 37 kb)

  PublisherDOI

• Insights into transcriptional changes that accompany organelle sequestration from the stolen nucleus of Mesodinium rubrum

  BMC Genomics · 2015-10-16 · 32 citations

  articleOpen access

  BACKGROUND: Organelle retention is a form of mixotrophy that allows organisms to reap metabolic benefits similar to those of photoautotrophs through capture of algal prey and sequestration of their plastids. Mesodinium rubrum is an abundant and broadly distributed photosynthetic marine ciliate that steals organelles from cryptophyte algae, such as Geminigera cryophila. M. rubrum is unique from most other acquired phototrophs because it also steals a functional nucleus that facilitates genetic control of sequestered plastids and other organelles. We analyzed changes in G. cryophila nuclear gene expression and transcript abundance after its incorporation into the cellular architecture of M. rubrum as an initial step towards understanding this complex system. METHODS: We compared Illumina-generated transcriptomes of the cryptophyte Geminigera cryophila as a free-living cell and as a sequestered nucleus in M. rubrum to identify changes in protein abundance and gene expression. After KEGG annotation, proteins were clustered by functional categories, which were evaluated for over- or under-representation in the sequestered nucleus. Similarly, coding sequences were grouped by KEGG categories/pathways, which were then evaluated for over- or under-expression via read count strategies. RESULTS: At the time of sampling, the global transcriptome of M. rubrum was dominated (~58-62 %) by transcription from its stolen nucleus. A comparison of transcriptomes from free-living G. cryophila cells to those of the sequestered nucleus revealed a decrease in gene expression and transcript abundance for most functional protein categories within the ciliate. However, genes coding for proteins involved in photosynthesis, oxidative stress reduction, and several other metabolic pathways revealed striking exceptions to this general decline. CONCLUSIONS: Major changes in G. cryophila transcript expression after sequestration by M. rubrum and the ciliate's success as a photoautotroph imply some level of control or gene regulation by the ciliate and at the very least reflect a degree of coordination between host and foreign organelles. Intriguingly, cryptophyte genes involved in protein transport are significantly under-expressed in M. rubrum, implicating a role for the ciliate's endomembrane system in targeting cryptophyte proteins to plastid complexes. Collectively, this initial portrait of an acquired transcriptome within a dynamic and ecologically successful ciliate highlights the remarkable cellular and metabolic chimerism of this system.

  PublisherOA PDFDOI

• Additional file 3: Table S3. of Insights into transcriptional changes that accompany organelle sequestration from the stolen nucleus of Mesodinium rubrum

  Figshare · 2015-01-01

  datasetOpen access

  Differential expression of KEGG pathways between GC and KN. GC and KN, mean expression values associated with each pathway calculated from the total number of reads per base pair (normalized read counts for each gene); P adj., P value as determined from Mann-Whitney tests and adjusted with a Benjamini and Hochberg false discovery rateâ

  PublisherDOI

• Eco‐evolutionary feedbacks between private and public goods: evidence from toxic algal blooms

  Ecology Letters · 2015-11-27 · 47 citations

  review

  The importance of 'eco-evolutionary feedbacks' in natural systems is currently unclear. Here, we advance a general hypothesis for a particular class of eco-evolutionary feedbacks with potentially large, long-lasting impacts in complex ecosystems. These eco-evolutionary feedbacks involve traits that mediate important interactions with abiotic and biotic features of the environment and a self-driven reversal of selection as the ecological impact of the trait varies between private (small scale) and public (large scale). Toxic algal blooms may involve such eco-evolutionary feedbacks due to the emergence of public goods. We review evidence that toxin production by microalgae may yield 'privatised' benefits for individual cells or colonies under pre- and early-bloom conditions; however, the large-scale, ecosystem-level effects of toxicity associated with bloom states yield benefits that are necessarily 'public'. Theory predicts that the replacement of private with public goods may reverse selection for toxicity in the absence of higher level selection. Indeed, blooms often harbor significant genetic and functional diversity: bloom populations may undergo genetic differentiation over a scale of days, and even genetically similar lineages may vary widely in toxic potential. Intriguingly, these observations find parallels in terrestrial communities, suggesting that toxic blooms may serve as useful models for eco-evolutionary dynamics in nature. Eco-evolutionary feedbacks involving the emergence of a public good may shed new light on the potential for interactions between ecology and evolution to influence the structure and function of entire ecosystems.

  PublisherDOI

• Additional file 5: Table S5. of Insights into transcriptional changes that accompany organelle sequestration from the stolen nucleus of Mesodinium rubrum

  Figshare · 2015-01-01

  datasetOpen access

  Description and classification of DESeq log2FC under-expressed genes in KN. Genes of note are in bold with parenthetical notation indicating the pathway to which they belong. Genes were assigned to their structural or enzymatic function (for example, “Chromosome”, “Cytoskeleton Proteins”, “Peptidases”, and “Ubiquitin System”) when they returned associations with categories not relevant to this system (for example, Human Diseases and Organismal Processes). (XLSX 48 kb)

  PublisherDOI

• Additional file 2: Table S2. of Insights into transcriptional changes that accompany organelle sequestration from the stolen nucleus of Mesodinium rubrum

  Figshare · 2015-01-01

  datasetOpen access

  Reduced protein count analyses for KEGG categories. Boldface, subcategories that are significantly over-or under-represented in KN in comparison to GC; Number of KOs; The number of KOs that belong to each subcategory where only one protein representative for each KO was included in the analysis; % of total, the relative contribution of each subcategory to the total number of KOs assigned by KEGG. (XLSX 10 kb)

  PublisherDOI

Recent grants

• DISSERTATION RESEARCH: Structured groups and the evolution of cooperation in pathogenic bacterial biofilms

  NSF · $15k · 2010–2013

• En-Gen: Gene expression and harmful algal bloom dynamics.

  NSF · $995k · 2007–2012

• DISSERTATION RESEARCH: Determining the role of horizontal gene transfer in plastid acquisition and endosymbiosis

  NSF · $15k · 2010–2012

Frequent coauthors

• Debashish Bhattacharya

  Rutgers, The State University of New Jersey

  34 shared

• Hwan Su Yoon

  Sungkyunkwan University

  24 shared

• Jennifer H. Wisecaver

  Purdue University System

  14 shared

• S. Li

  University of Iowa

  8 shared

• Marcelo B. Soares

  Illinois College

  7 shared

• Adrián Reyes‐Prieto

  University of New Brunswick

  7 shared

• Donald M. Anderson

  7 shared

• Valerie Burland

  University of Wisconsin–Madison

  6 shared

Awards & honors

• CICOR Postdoctoral Scholarship (2005)
• Robert T. Wilce Award, Northeast Algal Society (2005)
• NSF-Graduate Research Fellowship, honorable mention (2003)