Chemosensory genes and the evolution of aphid host races
Lead Research Organisation:
University of York
Department Name: Biology
Abstract
The process of speciation involves the progressive evolution of reproductive isolation between divergent populations. When this process happens in the face of gene flow, differentiation is expected to be variable across the genome reflecting the direct operation of natural selection and the barrier created for regions surrounding selected loci. Population genomics and QTL mapping approaches have recently contributed significantly to detecting regions under selection and associated islands of differentiation but further progress is difficult in many systems. We argue that a candidate gene approach can significantly advance this field. We propose to study sequence and expression divergence for the entire known repertoire of chemosensory genes in host races of the pea aphid. This study system is unique in having multiple races at different levels of divergence, excellent background information and a sequenced genome. This allows us to apply the latest approaches (Nimblegen capture arrays, 454 sequencing and Illumina Digitial Gene Expression) to this major problem in evolutionary genetics.
People |
ORCID iD |
| Julia Ferrari (Principal Investigator) |
Publications
Duvaux L
(2015)
Dynamics of copy number variation in host races of the pea aphid.
in Molecular biology and evolution
Eyres I
(2017)
Targeted re-sequencing confirms the importance of chemosensory genes in aphid host race differentiation.
in Molecular ecology
Eyres I
(2016)
Differential gene expression according to race and host plant in the pea aphid
in Molecular Ecology
Smadja CM
(2012)
Large-scale candidate gene scan reveals the role of chemoreceptor genes in host plant specialization and speciation in the pea aphid.
in Evolution; international journal of organic evolution
| Description | Our aim was to test the hypothesis that divergent selection has operated on a small subset of chemosensory genes during the formation of host races of pea aphid. We predicted that this selection would have generated either (1) patterns of sequence divergence that are atypical with respect to background divergence in randomly selected control loci, and the majority of chemosensory loci, or (2) differences in gene expression that are similarly atypical, or both. We have used a recently-published approach to check for copy-number variation and have found evidence for widespread duplication and loss which is non-randomly associated with gene families, being more common than expected in the odorant receptor genes. In some cases, copy number variation is strongly associated with race suggesting that it may play a role in host-associated differentiation. We have published results of a pilot capture experiment and we have also published the exciting and novel copy-number variation results. We have identified a small subset of chemosensory genes implicated in divergence between pea aphid host races through their role in host recognition. Surprisingly low gene expression responses to host-switching but large expression differences among races have been observed. These manuscripts are currently under review. Together, these observations take us closer to understanding the evolutionary steps underlying host race formation. |
| Exploitation Route | The main beneficiaries are the academic community through a deeper understanding of speciation genomics. However, we have communicated some of our findings to the agricultural sector to raise awareness of potential applications in agriculture in the future. We are taking forward these observations in our current grant by testing for selection on candidate genes and for association between these genes and the aphids' acceptance of hosts as a function of their metabolite composition. In general, this will help to understand how aphids make feeding decisions and may eventually help in development of methods for aphid control. |
| Sectors | Agriculture, Food and Drink |
| Description | The PI at Sheffield (Butlin) and Project Partner Zhou attended the CropWorld2012 conference in London and distributed a flier about the potential of our results to underpin the design of new aphid control strategies. |
| Description | Speciaphid |
| Organisation | French National Institute of Agricultural Research |
| Department | INRA Rennes Centre |
| Country | France |
| Sector | Public |
| PI Contribution | Our work on speciation in aphids and on the role of bacterial symbionts in aphids is done under the speciaphid agreement, an agreement between French and British researchers to coordinate their research efforts on this system, collaborate and share material. We have exchanged samples, data as well as meeting on a regular basis. |
| Collaborator Contribution | Our work on speciation in aphids and on the role of bacterial symbionts in aphids is done under the speciaphid agreement, an agreement between French and British researchers to coordinate their research efforts on this system, collaborate and share material. We have exchanged samples, data as well as meeting on a regular basis. |
| Impact | The collaboration involves researchers specialising in ecology, evolutionary biology, agricultural sciences, genomics and bioinformatics. |
| Start Year | 2012 |
| Description | Speciaphid |
| Organisation | University of Montpellier |
| Department | Institute of Evolutionary Sciences (ISEM) |
| Country | France |
| Sector | Academic/University |
| PI Contribution | Our work on speciation in aphids and on the role of bacterial symbionts in aphids is done under the speciaphid agreement, an agreement between French and British researchers to coordinate their research efforts on this system, collaborate and share material. We have exchanged samples, data as well as meeting on a regular basis. |
| Collaborator Contribution | Our work on speciation in aphids and on the role of bacterial symbionts in aphids is done under the speciaphid agreement, an agreement between French and British researchers to coordinate their research efforts on this system, collaborate and share material. We have exchanged samples, data as well as meeting on a regular basis. |
| Impact | The collaboration involves researchers specialising in ecology, evolutionary biology, agricultural sciences, genomics and bioinformatics. |
| Start Year | 2012 |
| Description | Speciaphid |
| Organisation | University of Oxford |
| Department | Department of Zoology |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | Our work on speciation in aphids and on the role of bacterial symbionts in aphids is done under the speciaphid agreement, an agreement between French and British researchers to coordinate their research efforts on this system, collaborate and share material. We have exchanged samples, data as well as meeting on a regular basis. |
| Collaborator Contribution | Our work on speciation in aphids and on the role of bacterial symbionts in aphids is done under the speciaphid agreement, an agreement between French and British researchers to coordinate their research efforts on this system, collaborate and share material. We have exchanged samples, data as well as meeting on a regular basis. |
| Impact | The collaboration involves researchers specialising in ecology, evolutionary biology, agricultural sciences, genomics and bioinformatics. |
| Start Year | 2012 |
| Description | Speciaphid |
| Organisation | University of Sheffield |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | Our work on speciation in aphids and on the role of bacterial symbionts in aphids is done under the speciaphid agreement, an agreement between French and British researchers to coordinate their research efforts on this system, collaborate and share material. We have exchanged samples, data as well as meeting on a regular basis. |
| Collaborator Contribution | Our work on speciation in aphids and on the role of bacterial symbionts in aphids is done under the speciaphid agreement, an agreement between French and British researchers to coordinate their research efforts on this system, collaborate and share material. We have exchanged samples, data as well as meeting on a regular basis. |
| Impact | The collaboration involves researchers specialising in ecology, evolutionary biology, agricultural sciences, genomics and bioinformatics. |
| Start Year | 2012 |
| Description | School Visit (York) |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Schools |
| Results and Impact | 60 primary school children attended this session, which sparked interest in entomology, aphids and ecology more generally |
| Year(s) Of Engagement Activity | 2017 |