Lead Research Organisation: Imperial College London
Department Name: Life Sciences


How species originate and diverge from their progenitor is one of the key questions in biology. Divergence resulting from geographical isolation is a well-known driving force of speciation, but in theory populations could also diverge into separate species in the absence of geographical isolation, a mechanism generally referred to as speciation with gene flow. Documented cases with very high initial gene flow remain rare. Savolainen et al. provided compelling evidence for in situ speciation in a case study of two species of palm in the genus Howea, H. forsteriana and H. belmoreana, strictly endemic to the minute Lord Howe Island (LHI) in the Tasman Sea. Although this case study is viewed by many as probably one of the most convincing examples of sympatric speciation to date, it has still been hotly debated. Speciation in the face of high gene flow would occur most readily when ecological traits under divergent selection (e.g. soil preference or foraging behaviour) and traits associated with assortative mating (e.g. flowering time or body size) are correlated genetically. The two Howea palm species have distinct peaks of flowering time and have contrasting distributions related to substrate preferences: H. belmoreana is restricted to the older volcanic rocks, whereas H. forsteriana grows predominantly on calcareous soils but also on volcanic soils in disturbed sites. Given these features, a scenario for ecological speciation has been proposed. However, although ecological speciation is thought to be a major generator of biodiversity, the genetic basis behind this process is still poorly understood. Here, building on our previous research, we will determine the mechanisms of reproductive isolation in the evolution of sympatric Howea palms and identify the genes underlying speciation.

Planned Impact

We propose four lines of action to increase impact:

1. Scientific papers in high-profile journals and oral presentation at the 'Evolution Conference' in the USA to reach out the academic community.

2. Lay reports about our research sent to the LHI Governing Board and NEW South Wales Conservation Authority

3. With our current NERC Impact Acceleration Award, we will organise a workshop with industry stakeholder at the end of this year. We propose to follow up with another workshop in mid project (2015) to explore potential commercialisation or amelioration of current palm varieties. This workshop will last for 2 days and be hosted at Imperial College at Silwood Park to discuss business plans with key partners indicated in the Pathway to Impact. We will involve the LHI nursery and the major growers that currently sell kentias (mainly in The Netherlands) to discuss how our genomic research could help improve the varieties they sell. We will also need to consider our obligations under the International Convention on Biological Diversity (CBD), and particularly with regard to 'access and benefit sharing'. Any commercialisation of forms derived from the wild populations of the palms, and any commercialisation process based on genetic material derived from the island, should involve a return, either as a share of the profits from the sale of the cultivar, or in the form of in-kind benefits to the source country. LHI is a UNESCO-designated World Heritage Site with unique biodiversity and a well-developed biodiversity conservation action plan. Our research could both benefit the management of these ecosystems and the livelihood of its inhabitants. Our workshops will target these issues.

4. Finally, we propose to commission an innovative film - 'how evolution is true' to communicate the excitement, innovation and significance of this research in evolution. Kew has a proven track record of working with creative film-makers (e.g. http://lonelyleap.com/) to deliver inspiring, scientist-led short, documentaries that communicate to in an accessible and inspiring way. Drawn together in Kew's "Beyond the Garden" series, these have delivered science messages to entirely new audiences. For example, a film detailing Kew's work on coffee and climate change (Kew, the Forgotten Home of Coffee http://vimeo.com/67890000) has received ca. 100,000 views across various channels and is nominated for a short film prize in the 2014 Panda Awards at the Wildscreen festival. A second film documenting Kew's research on plant phylogenetics (The Plant Family Tree http://vimeo.com/72741977) has been profiled on the highly selective global cultural platform www.nowness.com. We will draw on this film to commission a film that would educate, communicate, and present the evolution and origin of species on Earth to a wider audience. The film will be presented at various media competition, featured in the galleries at Kew and be posted on our websites, facebook and YouTube. We will also contact famous media personalities to publicise our film, including Jerry Coyne's blog 'Why Evolution is True' and the Richard Dawkins Foundation on 'evolution is not a controversial issue'.


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Ciezarek AG (2019) Phylotranscriptomic Insights into the Diversification of Endothermic Thunnus Tunas. in Molecular biology and evolution

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Coathup MJ (2019) How predictable is genome evolution? in eLife

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Hipperson H (2016) Ecological speciation in sympatric palms: 2. Pre- and post-zygotic isolation. in Journal of evolutionary biology

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Igea J (2015) A comparative analysis of island floras challenges taxonomy-based biogeographical models of speciation. in Evolution; international journal of organic evolution

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Osborne OG (2020) Sympatric speciation in mountain roses (Metrosideros) on an oceanic island. in Philosophical transactions of the Royal Society of London. Series B, Biological sciences

Description Ecological speciation requires divergent selection, reproductive isolation and a genetic mechanism to link the two. We examined the role of gene expression and coding sequence evolution in this process using two species of Howea palms that have diverged sympatrically on Lord Howe Island, Australia. These palms are associated with distinct soil types and have displaced flowering times, representing an ideal candidate for ecological speciation. We generated large amounts of RNA-Seq data from multiple individuals and tissue types collected on the island from each of the two species. We found that differentially expressed loci as well as those with divergent coding sequences between Howea species were associated with known ecological and phenotypic differences, including response to salinity, drought, pH and flowering time. From these loci, we identified potential 'ecological speciation genes' and further validate their effect on flowering time by knocking out orthologous loci in a model plant species. Finally, we put forward six plausible ecological speciation loci, providing support for the hypothesis that pleiotropy could help to overcome the antagonism between selection and recombination during speciation with gene flow.
Exploitation Route possibly genes of interest for plant drought and salt tolerance
Sectors Environment

Title Palm ecological experiment data 
Description The dataset describes the effect of soil type, soil sterilisation and drought treatment on survival rate and growth of Howea belmoreana and Howea forsteriana, grown from seed in an experiment on Lord Howe Island for 30 months. The data describe the number of surviving plants per replicate, as well as height and number of leaves of individual plants at two time-points. Currently embargoed until publication, will be publicly available by November 2021. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? No  
Impact NA 
Title fasta_alignment_filters 
Description Python scripts for filtering and manipulation of fasta format alignment data 
Type Of Technology Software 
Year Produced 2019 
Open Source License? Yes  
Impact NA 
URL https://github.com/ogosborne/fasta_alignment_filters