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Details of Award

NERC Reference : NE/R001324/1

Excavating the roots of the tree of life: revealing a billion year fossil record for the euglenids

Grant Award

Principal Investigator:
Professor CH Wellman, University of Sheffield, School of Biosciences
Co-Investigator:
Dr P Christin, University of Sheffield, School of Biosciences
Co-Investigator:
Dr W Fraser, Oxford Brookes University, Faculty of Humanities and Social Sci
Science Area:
Earth
Freshwater
Terrestrial
Overall Classification:
Panel C
ENRIs:
Biodiversity
Global Change
Natural Resource Management
Science Topics:
Systematics & Taxonomy
Palaeoenvironments
Microorganisms
Abstract:
In establishing the theory of evolution Charles Darwin realized that life originated only once and over billions of years diversified, through evolution, into the bewildering diversity of life on Earth today. Since this monumental paradigm shift a major goal of biology has been to establish the 'true tree of life' in terms of evolutionary relationships of the different types of organism and timing of their divergence. The most problematic and least understood regions of the tree of life are its deep roots: the origin of life and its early diversification. This is because these events occurred billions of years ago in the deep past and: (i) the primary divergence into the three domains of life (bacteria, archaea, eukaryotes) involved a complicated combining of organisms in 'endosymbiotic events'; (ii) the organisms involved are unfamiliar because modern relatives, if any, have changed dramatically through time; (iii) the fossil record is poor in rocks from such ancient times; (iv) techniques such as molecular clock analyses become unreliable the further back in time one investigates. The euglenids are a bizarre group of single-celled organisms common on the planet today. They inhabit freshwater environments where they move through the water using a unique motion called 'peristaltic movement'. Intriguingly, they either feed by ingesting matter (like animals) or through harvesting the Sun's energy (like plants). It is believed that they can do the latter because they combined with a photosynthetic unicellular green algae during a 'secondary endosymbiotic event'. Euglenoids are familiar to many of us as they are routinely examined in elementary laboratory classes, to familiarise students with the basic features of single-celled eukaryotes and the fact that some display characteristics of both animals and plants. Euglenids are particularly fascinating because studies of their anatomy and genome suggest they are among the most primitive of the earliest eukaryote organisms (that is organisms that have a true cell and evolved through the combination of more basic organisms (bacteria and archaea) that lack a true cell). Unfortunately euglenids lack a recognisable fossil record so we know little regarding their origin and evolutionary history. In order to remedy this major problem we have trawled the literature and discovered a number of fossils that have euglenid-like characters. Our insight is that we have discovered a way of recognising whether a fossil does indeed represent a true euglenid. Modern euglenids have a unique cell wall structure, and by taking extremely thin sections of their cell walls (less that 1/10,000 mm in thickness) and examining them under a powerful Transmission Electron Microscope, it is possible to identify this unique structure. We have undertaken preliminary studies on potential fossil euglenids and demonstrated that we can observe such structure in the fossils and hence prove that they are indeed euglenids. Some of the euglenid-like fossils are a staggering 1 billion years old. Our proposal is to analyse potential euglenid fossils from throughout the geological column and, by demonstrating which possess the characteristic euglenid wall structure, provide a continuous fossil record for the euglenids. This will place euglenids as one of the few groups of early divergent eukaryotes with a deep fossil record (and the first of the SuperGroup Excavates). This is important because it will provide evidence for the timing and nature of the diversification of the earliest eukaryotes. It will also provide an important fossil calibration point for molecular biologists that undertake molecular clock studies. Furthermore, we are addressing a highly topical research area and our findings will fuel current controversies concerning whether the eukaryotes evolved in the ocean or in fresh water and how and when euglenids acquired their secondary endosymbiotic green alga.
Period of Award:
1 Nov 2017 - 30 Jun 2021
Value:
£253,939
Authorised funds only
NERC Reference:
NE/R001324/1
Grant Stage:
Completed
Scheme:
Standard Grant FEC
Grant Status:
Closed
Programme:
Standard Grant

This grant award has a total value of £253,939  

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FDAB - Financial Details (Award breakdown by headings)

DI - Other CostsIndirect - Indirect CostsDA - InvestigatorsDI - StaffDA - Estate CostsDI - T&SDA - Other Directly Allocated
£14,330£54,785£48,134£69,426£16,520£45,449£5,297

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