Hybridization and the origin of novel taxa in Euphrasia

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Biological Sciences

Abstract

Our planet has a huge number of different species, and I am striving to understand the way this diversity has formed. Recently, it has been suggested that cross-mating between species (hybridization) under natural settings, may be the first stage in producing some of these new species. This may play an important role in evolution, as unlike most species which evolve over hundreds-of-thousands or millions of years, it would be possible for a new species to form much more rapidly, in less than 100 generations. However, there are many unanswered questions about this area of evolutionary biology, such as: why does hybridization between species happen so often in some organisms and not others? And when does this produce a new species? This research will address these questions in a group of native plants where hybridization between species is common.

Eyebrights (Euphrasia) are a group of 19 species found throughout the UK. Unlike many other organisms, hybridization is common, and thought to give rise to a number of new species that are found only in the UK. One such example is the slender-heath eyebright (E. micrantha) and the common eyebright (E. officinalis), which are parents to two new species (E. rivularis and E. vigursii). To understand the way these new species have evolved, I will be collecting eyebrights from across the UK, and using state-of-the-art DNA sequencing techniques to determine the contribution of each of the parent species to the DNA of the new hybrid species. Each of these techniques will allow predictions about the outcomes of hybridization to be tested. For example, it may be predicted that one species will contribute more genes to the new species than the other. This would arise when a species produces larger flowers that are more attractive to pollinators, and so the initial hybrid will go on to mate recurrently with this large flowered species. When this occurs over many generations, most genes will come from one parent, with just a few from the other parent. By sequencing a large number of genes in the new species, as well as both the parents, we can compare the proportion coming from each of the parents.

Overall, these results will greatly help our understanding of the way new species evolve, particularly rare species that are of recent origin (in the last 10,000 years). This is of great importance to conservationists in the UK, who are trying to protect rare and endangered species. By understanding the way new eyebright species have evolved, conservation biologists can make new plans that help protect the processes involved in generating new species. This will ensure the survival of not only rare species that are currently present, but those which may evolve in the near future. Such action plans would include conserving pairs of species that hybridize and are known to produce hybrid species, as well as maintaining areas of habitat that favour hybridization.

Planned Impact

Evolutionary biologists using NGS will greatly benefit from the resources generated through this project. Protocols, bioinformatics scripts, and expertise developed will provide NGS users with new tools to address evolutionary questions in non-model organisms. As the University of Edinburgh is emerging as an international centre of excellence in the use of RAD sequencing, this project will enhance this profile by applying other genotyping-by-sequencing approaches, and associated NGS techniques, to a wider range of non-model organisms. Given the fast-pace at which these approaches are developing, and the way results can be rapidly publicised through social media outlets, this will likely make a considerable impact early in the project (within 3 years).

Results from this work will be of practical use for conservation biologists and land managers, as well as policy making agencies at the national level. An improved understanding of the evolutionary processes underlying speciation in Euphrasia will address conservation questions such as:
1) How distinct are natural populations of hybrid Euphrasia species? This will allow conservation biologists to address the best source of genetic material for supplementing declining populations.
2) Are hybrid zones actively generating novel taxa? If so, these may be considered areas of conservation priority.
3) Which areas are 'hot spots' of chloroplast genetic diversity? These sites may also be considered as areas requiring conservation measures.
These outcomes are hoped to indirectly improve quality of life of British citizens. By giving reliable information to conservation agencies, they will be able focus funds for conservation work in the most suitable way, for example by conserving the most threatened natural populations of wildflowers.

Wildlife recorders and national charities (e.g. Botanical Society of the British Isles, Botanical Society of Scotland, British Ecological Society, Plantlife) will benefit from the results and resources generated through this project. The citizen-science collection approach (see Pathways to Impact) will be an important means to engage this community, and the news articles and talks given will educate them on the importance of recording all species in the wild, not just obvious species that are easy to identify. Moreover, it is hoped that the website forum, as well as walks and workshops, will facilitate networking between wildlife records, encouraging an exchange in knowledge and expertise.

The general public (interested in plants, gardens and natural history) will benefit from science communication activities associated with the project. They will be educated in the role hybridization plays in the wild (and more generally about principles of evolutionary biology), as well as having an increased appreciation of wild plant species growing in the local area. It is hoped this will improve quality of life by encouraging people to go outside and enjoy natural areas. Similarly, school children (particularly secondary school students), will benefit from workshops and the resource pack on hybridization. It is hoped the in addition to the general outcomes of appreciating wild species, and improving education relating to evolutionary biology, they will be made aware that evolutionary research is a potential career route for those interested in understanding the natural world.

The NERC fellow would benefit from a greatly improved set of research skills. In particular, advanced training in the generation and analysis of next-generation sequencing data would represent a highly employable set of skills. This training strongly reflects themes explored in the NERC Science Theme of Biodiversity, where new sequencing approaches are used to explore the processes generating species diversity.

Publications


10 25 50

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Hollingsworth PM (2016) Telling plant species apart with DNA: from barcodes to genomes. in Philosophical transactions of the Royal Society of London. Series B, Biological sciences


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Twyford AD (2015) Adaptive divergence in the monkey flower Mimulus guttatus is maintained by a chromosomal inversion. in Evolution; international journal of organic evolution


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Twyford AD (2016) Strategies for complete plastid genome sequencing. in Molecular ecology resources


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Twyford Alex D. (2017) New insights into the population biology of endoparasitic Rafflesiaceae in AMERICAN JOURNAL OF BOTANY

 
Description NERC NBAF
Amount £5,600 (GBP)
Funding ID NBAF1031 
Organisation Natural Environment Research Council (NERC) 
Sector Public
Country United Kingdom of Great Britain & Northern Ireland (UK)
Start 01/2017 
End 04/2017
 
Description Natural History Museum's Science Uncovered, Fri 25 Sept 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Presenting parasitic plants to the general public at this large scientific engagement event.
Year(s) Of Engagement Activity 2015