Welcome


I am a fifth-year graduate student in Greg Wray's Lab in the Biology Department at Duke University.

Current Research

I'm interested in the evolutionary and ecological drivers of organismal diversity, especially the consequences of genomic and environmental changes on marine invertebrate developmental evolution. I am researching the sea urchin genus Heliocidaris (see figure below) to better understand the molecular mechanisms underlying life history evolution and radical developmental modifications associated with lecithotrophy including altered embryonic differentiation, morphogenesis, and rapid development.

In this system, Heliocidaris tuberculata exhibits planktotrophic development (feeding larval form) and metamorphoses into an adult after spending 3-5 weeks feeding in the plankton. The closely related Heliocidaris erythrogramma, however, develops through a highly-derived lecithotrophic (non-feeding) larval form that metamorphoses into an adult just 4-5 days after fertilization. The evolution of lecithotrophic development is accompanied by dramatic changes to reproduction, physiology, and embryogenesis, and the its repeated occurrence across many marine invertebrate groups has major ecological implications

Much of this work is done in collaboration with Dr. Maria Byrne at the University of Sydney.

CV download: CV_PDavidson_03Dec2020

    Cis-regulatory evolution and evo-devo

    My main project investigates how developmental cis-regulatory mechanisms have evolved in H. erythrogramma relative to indirect, planktotrophic sea urchins species. I aim to better understand how these regulatory changes are associated with the unique developmental program of H. erythrogramma, such as altered embryonic cell fate specification.

    Sea urchin comparative genomics

    I am assembling, annotating, and comparing the genomes of a few different sea urchin species at chromosomal-resolution including Lytechinus variegatus (now published), H. erythrogramma, and H. tuberculata. The aim of this work is to identify genomic drivers underlying the evolution of lecithotrophy and organismal novelty.

    Past Research

      Global climate change and marine invertebrate development

      This projected included researching the effect of ocean acidification on gene expression during embryogenesis and larval development in H. erythrogramma to interpret how future global climate change may affect marine invertebrate development, settlement, and dispersal.

      Life history evolution and developmental physiology

      This work used liquid chromatography tandem-mass spectrometry to analyze lipidomic and proteomic differences in the eggs and larvae of H. erythrogramma, H. tuberculata, and Lytechinus variegatus (another planktotrophic sea urchin). The aim of this study was to better understand molecular-level, metabolic adaptations underlying rapid, non-feeding larval development.

      Ctenophore evo-devo

      I previously worked as an undergraduate in the Browne Lab at the University of Miami studying the evolution and development of ctenophores. I researched embryonic gene expression in Mnemiopsis leidyi (pictured left) using RNA-sequencing to better understand activation of the zygotic genome and early blastomere fate specification.

Publications

5) Devens, HR*, Davidson, PL*, Deaker, DJ, Smith, KE, Wray, GA, Byrne, M. Ocean acidification induces distinct transcriptomic responses across life history stages of the sea urchin Heliocidaris erythrogramma. Molecular Ecology. 29: 4618-4636. https://doi.org/10.1111/mec.15664.

4) Byrne, M, Koop, D, Strbenac, D, Cisternas, Paula, Balogh, R, Yang, JYH, Davidson, PL, Wray, GA. (2020) Transcriptomic analysis of sea star development through metamorphosis to the highly derived pentameral body plan with a focus on neural transcription factors. DNA Research. 27: dsaa007. https://doi.org/10.1093/dnares/dsaa007.

3) Davidson, PL*, Guo, H*, Wang, L, Berrio, A, Zhang, H, Chang, Y, Soborowski, AL, McClay, DR, Fan, G, Wray, GA. (2020) Chromosomal-Level genome assembly of the sea urchin Lytechinus variegatus substantially improves functional genomic analyses. Genome Biology and Evolution. 12: 1080–1086. https://doi.org/10.1093/gbe/evaa101.

2) Davidson, PL, Thompson, JW, Foster, MW, Moseley, MA, Byrne, M, Wray, GA. (2019) A comparative analysis of egg provisioning using mass spectrometry during rapid life history evolution in sea urchins. Evolution and Development. 21: 188-204. http://dx.doi.org/10.1111/ede.12289.

1) Davidson, PL, Koch, BJ, Schnitzler, CE, Henry, JQ, Martindale, MQ, Baxevanis, AD, Browne, WE. (2017) The maternal-zygotic transition and zygotic activation of Mnemiopsis leidyi genome occurs within the first three cell cycles. Molecular Reproduction and Development. 84: 1218-1229. http://dx.doi.org/10.1002/mrd.22926. Featured as journal issue cover.

*equal contribution

Contact

Email: phillip.davidson@duke.edu
Twitter: @PhilDavidson
Lab phone: ​(919) 668-6249