Bio

Academic Appointments


Boards, Advisory Committees, Professional Organizations


  • Chair, Division of Evolutionary Developmental Biology, Society of Integrative and Comparative Biology (2012 - Present)

Professional Education


  • BSc. Hons, University of Sussex, Biology with European Studies (1991)
  • PhD, Dept of Ecology and Evolution, SUNY Stony Brook, Ecology and Evolution (1998)

Research & Scholarship

Current Research and Scholarly Interests


Evolution and development, specifically the evolution of the deuterostomes

Teaching

2013-14 Courses


Postdoctoral Advisees


Graduate and Fellowship Programs


  • Biology (School of Humanities and Sciences) (Phd Program)

Publications

Journal Articles


  • FGF signaling induces mesoderm in the hemichordate Saccoglossus kowalevskii DEVELOPMENT Green, S. A., Norris, R. P., Terasaki, M., Lowe, C. J. 2013; 140 (5): 1024-1033

    Abstract

    FGFs act in vertebrate mesoderm induction and also play key roles in early mesoderm formation in ascidians and amphioxus. However, in sea urchins initial characterizations of FGF function do not support a role in early mesoderm induction, making the ancestral roles of FGF signaling and mechanisms of mesoderm specification in deuterostomes unclear. In order to better characterize the evolution of mesoderm formation, we have examined the role of FGF signaling during mesoderm development in Saccoglossus kowalevskii, an experimentally tractable representative of hemichordates. We report the expression of an FGF ligand, fgf8/17/18, in ectoderm overlying sites of mesoderm specification within the archenteron endomesoderm. Embryological experiments demonstrate that mesoderm induction in the archenteron requires contact with ectoderm, and loss-of-function experiments indicate that both FGF ligand and receptor are necessary for mesoderm specification. fgf8/17/18 gain-of-function experiments establish that FGF8/17/18 is sufficient to induce mesoderm in adjacent endomesoderm. These experiments suggest that FGF signaling is necessary from the earliest stages of mesoderm specification and is required for all mesoderm development. Furthermore, they suggest that the archenteron is competent to form mesoderm or endoderm, and that FGF signaling from the ectoderm defines the location and amount of mesoderm. When considered in a comparative context, these data support a phylogenetically broad requirement for FGF8/17/18 signaling in mesoderm specification and suggest that FGF signaling played an ancestral role in deuterostome mesoderm formation.

    View details for DOI 10.1242/dev.083790

    View details for Web of Science ID 000314879800011

    View details for PubMedID 23344709

  • Identical Genomic Organization of Two Hemichordate Hox Clusters CURRENT BIOLOGY Freeman, R., Ikuta, T., Wu, M., Koyanagi, R., Kawashima, T., Tagawa, K., Humphreys, T., Fang, G., Fujiyama, A., Saiga, H., Lowe, C., Worley, K., Jenkins, J., Schmutz, J., Kirschner, M., Rokhsar, D., Satoh, N., Gerhart, J. 2012; 22 (21): 2053-2058

    Abstract

    Genomic comparisons of chordates, hemichordates, and echinoderms can inform hypotheses for the evolution of these strikingly different phyla from the last common deuterostome ancestor. Because hox genes play pivotal developmental roles in bilaterian animals, we analyzed the Hox complexes of two hemichordate genomes. We find that Saccoglossus kowalevskii and Ptychodera flava both possess 12-gene clusters, with mir10 between hox4 and hox5, in 550 kb and 452 kb intervals, respectively. Genes hox1-hox9/10 of the clusters are in the same genomic order and transcriptional orientation as their orthologs in chordates, with hox1 at the 3' end of the cluster. At the 5' end, each cluster contains three posterior genes specific to Ambulacraria (the hemichordate-echinoderm clade), two forming an inverted terminal pair. In contrast, the echinoderm Strongylocentrotus purpuratus contains a 588 kb cluster of 11 orthologs of the hemichordate genes, ordered differently, plausibly reflecting rearrangements of an ancestral hemichordate-like ambulacrarian cluster. Hox clusters of vertebrates and the basal chordate amphioxus have similar organization to the hemichordate cluster, but with different posterior genes. These results provide genomic evidence for a well-ordered complex in the deuterostome ancestor for the hox1-hox9/10 region, with the number and kind of posterior genes still to be elucidated.

    View details for DOI 10.1016/j.cub.2012.08.052

    View details for Web of Science ID 000311060200028

    View details for PubMedID 23063438

  • Evolutionary crossroads in developmental biology: hemichordates DEVELOPMENT Roettinger, E., Lowe, C. J. 2012; 139 (14): 2463-2475

    View details for DOI 10.1242/dev.066712

    View details for Web of Science ID 000305826000003

  • Ancient deuterostome origins of vertebrate brain signalling centres NATURE Pani, A. M., Mullarkey, E. E., Aronowicz, J., Assimacopoulos, S., Grove, E. A., Lowe, C. J. 2012; 483 (7389): 289-U79

    Abstract

    Neuroectodermal signalling centres induce and pattern many novel vertebrate brain structures but are absent, or divergent, in invertebrate chordates. This has led to the idea that signalling-centre genetic programs were first assembled in stem vertebrates and potentially drove morphological innovations of the brain. However, this scenario presumes that extant cephalochordates accurately represent ancestral chordate characters, which has not been tested using close chordate outgroups. Here we report that genetic programs homologous to three vertebrate signalling centres-the anterior neural ridge, zona limitans intrathalamica and isthmic organizer-are present in the hemichordate Saccoglossus kowalevskii. Fgf8/17/18 (a single gene homologous to vertebrate Fgf8, Fgf17 and Fgf18), sfrp1/5, hh and wnt1 are expressed in vertebrate-like arrangements in hemichordate ectoderm, and homologous genetic mechanisms regulate ectodermal patterning in both animals. We propose that these genetic programs were components of an unexpectedly complex, ancient genetic regulatory scaffold for deuterostome body patterning that degenerated in amphioxus and ascidians, but was retained to pattern divergent structures in hemichordates and vertebrates.

    View details for DOI 10.1038/nature10838

    View details for Web of Science ID 000301481800040

    View details for PubMedID 22422262

  • Animal Evolution: A Soap Opera of Unremarkable Worms CURRENT BIOLOGY Lowe, C. J., Pani, A. M. 2011; 21 (4): R151-R153

    Abstract

    Recent phylogenies have suggested that acoelomorph flatworms might provide insights into the nature of the ancestor of bilaterian animals. However, according to new data acoelomorphs might instead be degenerate deuterostomes closely related to Xenoturbella, muddying the waters of early animal evolution.

    View details for Web of Science ID 000287767600008

    View details for PubMedID 21334293

  • Structural shifts of aldehyde dehydrogenase enzymes were instrumental for the early evolution of retinoid-dependent axial patterning in metazoans PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Sobreira, T. J., Marletaz, F., Simoes-Costa, M., Schechtman, D., Pereira, A. C., Brunet, F., Sweeney, S., Pani, A., Aronowicz, J., Lowe, C. J., Davidson, B., Laudet, V., Bronner, M., De Oliveira, P. S., Schubert, M., Xavier-Neto, J. 2011; 108 (1): 226-231

    Abstract

    Aldehyde dehydrogenases (ALDHs) catabolize toxic aldehydes and process the vitamin A-derived retinaldehyde into retinoic acid (RA), a small diffusible molecule and a pivotal chordate morphogen. In this study, we combine phylogenetic, structural, genomic, and developmental gene expression analyses to examine the evolutionary origins of ALDH substrate preference. Structural modeling reveals that processing of small aldehydes, such as acetaldehyde, by ALDH2, versus large aldehydes, including retinaldehyde, by ALDH1A is associated with small versus large substrate entry channels (SECs), respectively. Moreover, we show that metazoan ALDH1s and ALDH2s are members of a single ALDH1/2 clade and that during evolution, eukaryote ALDH1/2s often switched between large and small SECs after gene duplication, transforming constricted channels into wide opened ones and vice versa. Ancestral sequence reconstructions suggest that during the evolutionary emergence of RA signaling, the ancestral, narrow-channeled metazoan ALDH1/2 gave rise to large ALDH1 channels capable of accommodating bulky aldehydes, such as retinaldehyde, supporting the view that retinoid-dependent signaling arose from ancestral cellular detoxification mechanisms. Our analyses also indicate that, on a more restricted evolutionary scale, ALDH1 duplicates from invertebrate chordates (amphioxus and ascidian tunicates) underwent switches to smaller and narrower SECs. When combined with alterations in gene expression, these switches led to neofunctionalization from ALDH1-like roles in embryonic patterning to systemic, ALDH2-like roles, suggesting functional shifts from signaling to detoxification.

    View details for DOI 10.1073/pnas.1011223108

    View details for Web of Science ID 000285915000044

    View details for PubMedID 21169504

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