Overview

Project Highlights:

  • Your research will be high impact science geared towards the conservation of bumble bees - highly important pollinators of both wild flowers and important crops.
  • Your research will be relevant to the ~240 species of bumble bee world-wide and also to the 20% of all insects that have haplo-diploid sex determination.
  • You will gain invaluable skills in bioinformatics and the analysis of ‘big data’ from next generation sequencing, and present your research at national and international conferences.

 

Bumble bees are a diverse group of key pollinators that suffer from the negative impact of anthropogenic change. This results in declining and fragmented populations that impacts on the bees themselves and so on the wild flowers and crops that they pollinate [1,2]

Importantly, the genetics and life-history of bumble bees make these changes especially damaging [3].

The aim of this PhD research is to investigate two understudied and important genetic issues relevant to the persistence of bumble bee populations in changing environments.

Haplodiploidy. Female bees (workers and queens) are diploid (maternal and paternal genome copies), whereas males are usually haploid (maternal copy only). An upshot is that natural selection potentially acts more effectively because genetic dominance is absent in genes expressed in males. Compared to diplo-diploids (like us), theory predicts that mildly deleterious variants – potentially important for future adaptation to changing environments – are more efficiently removed by selection, whereas adaptive but recessive variation is more likely fixed by selection.

Sex determination. Bumble bee sex is thought to be determined by a single genetic locus: the complimentary sex determination locus (CSD). Normally, heterozygotes develop as females, while hemizygotes (haploid) develop as males. However, inbreeding or reduced genetic variation caused by declining populations leads to diploid homozygotes at CSD which develop as diploid males. Diploid males have an enormous impact on population fitness as they replace valuable workers.

Importantly, theory shows that diploid male production greatly increases the likelihood of population extinction [4].

Currently we have little empirical data on whether natural selection is more efficacious in haplodiploid species or on the level of genetic variation at the CSD locus. The aim of this PhD is to help fill this knowledge gap.

Questions to answer include:

  1. Are there lower levels of potentially deleterious genetic variation:
    1. in bumble bees compared to diploid insects?
    2. in male expressed genes compared to female expressed genes within bumble bees?
  2. What genetic variation is at CSD in bumble bees?
  3. Does decreased genetic variation at CSD correlate with population extinction?
Foraging Bombus terrestris worker collecting pollen and nectar for its colony and pollinating flowers as a consequence.

Methodology

The project will use a combination of genomic analysis coupled with fieldwork (bee collection) and laboratory crosses.

Principal methods will be:

  • Bee husbandry (crosses to produce diploid males)
  • Molecular biology (DNA extraction, DNA sequencing)
  • High throughput massively parallel genome sequencing.
  • Bioinformatics (Linux environment, shell scripting, Python programming, use of R for statistics).
  • Quantitative analysis of genetic variation.

Training and Skills

Bioinformatics skills are essential in ‘big data’ modern biology, especially evolutionary and environmental biology. You will gain highly transferable skills in: biological computing and programming (e.g. PERL, Python, R), handling next generation sequencing data in a Linux environment, transcriptome assembly, molecular evolutionary analysis, manuscript preparation and giving presentations.

In addition to CENTA training you will receive tailored training from:

Supervisors directly (e.g. population genetics theory)

Workshops offered by Leicester’s Biostatistics and Bioinformatics Support Hub (BBASH)

University of Leicester courses (e.g. R, Python)

 

Timeline

Year 1: Familiarisation with the literature, sample collection, bee husbandry, DNA extraction, genome sequencing. Bioinformatics skills development.

Year 2: Analysis of bumble bee crosses, bioinformatics analysis of sequencing data. Conference poster presentation.

Year 3: Bioinformatic analysis of sequencing data Manuscript preparation / thesis preparation. Presentation of results at international conference.

Partners and collaboration (including CASE)

This project is being developed in partnership with Twycross Zoo. Part of Twycross’s mission aims to support studies within the following areas:

  • Conservation
  • Native Species
  • Sustainability and Biodiversity

You will be expected to spend ~3 months helping develop visitor information about bumble bees, their conservation status and the influence of their genetics on their persistence. This will be an excellent opportunity to showcase your work to a wide audience.

Further Details

Please contact Dr Rob Hammond, University of Leicester.

Email: rh22@le.ac.uk

Phone: 0116 252 5302

Website: https://www2.le.ac.uk/departments/genetics/people/hammond