Publication Date:
2015-07-02
Description:
Multicellularity is often considered a prerequisite for morphological complexity, as seen in the camera-type eyes found in several groups of animals. A notable exception exists in single-celled eukaryotes called dinoflagellates, some of which have an eye-like 'ocelloid' consisting of subcellular analogues to a cornea, lens, iris, and retina. These planktonic cells are uncultivated and rarely encountered in environmental samples, obscuring the function and evolutionary origin of the ocelloid. Here we show, using a combination of electron microscopy, tomography, isolated-organelle genomics, and single-cell genomics, that ocelloids are built from pre-existing organelles, including a cornea-like layer made of mitochondria and a retinal body made of anastomosing plastids. We find that the retinal body forms the central core of a network of peridinin-type plastids, which in dinoflagellates and their relatives originated through an ancient endosymbiosis with a red alga. As such, the ocelloid is a chimaeric structure, incorporating organelles with different endosymbiotic histories. The anatomical complexity of single-celled organisms may be limited by the components available for differentiation, but the ocelloid shows that pre-existing organelles can be assembled into a structure so complex that it was initially mistaken for a multicellular eye. Although mitochondria and plastids are acknowledged chiefly for their metabolic roles, they can also be building blocks for greater structural complexity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gavelis, Gregory S -- Hayakawa, Shiho -- White, Richard A 3rd -- Gojobori, Takashi -- Suttle, Curtis A -- Keeling, Patrick J -- Leander, Brian S -- England -- Nature. 2015 Jul 9;523(7559):204-7. doi: 10.1038/nature14593. Epub 2015 Jul 1.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada. ; 1] Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada [2] Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada [3] Center for Information Biology, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan. ; Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada. ; 1] Center for Information Biology, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan [2] Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia. ; 1] Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada [2] Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada [3] Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada [4] Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada. ; 1] Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada [2] Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada. ; 1] Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada [2] Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada [3] Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26131935" target="_blank"〉PubMed〈/a〉
Keywords:
Dinoflagellida/*genetics/physiology/*ultrastructure
;
Genome, Protozoan/genetics
;
Microscopy, Electron, Scanning
;
Microscopy, Electron, Transmission
;
Mitochondria/metabolism/ultrastructure
;
Molecular Sequence Data
;
Plastids/metabolism/ultrastructure
;
Protozoan Proteins/genetics
;
Rhodophyta/genetics
;
*Symbiosis
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
