Insect Molecular Genetics

16/05/2014 – Heliconius Butterfly wing pattern evolver game now online!

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Come and test your skills as a tropical flycatcher and see if you can spot the differences between tasty and yucky butterflies in this fun game based on the genetic evolution of mimicry. Game developed by David Griffiths as part of a Royal Society exhibit produced by the universities of Cambridge, York and Exeter.

You can link out to a full screen version of the game by clicking here.

18/05/2012 – Heliconius genome is published in Nature.


Our team has carried out groundbreaking DNA sequencing work in the laboratories at the Cornwall Campus, as part of an international study that has revealed the key behind the butterfly’s unusual ability to mimic other butterflies.

A first for science, the genome-sequencing work is the product of an international group of researchers, dubbed the Heliconius Genome Consortium, which examined the genome of the Postman butterfly (Heliconius melpomene), a well-known species that lives in the Peruvian Amazon. Using that data as a guide, we examined the genetic make-up of two other closely-related butterfly species – Heliconius timareta and Heliconius elevatus.

These butterflies are found in the tropical and sub-tropical regions of the Americas, from the Amazon basin to Texas and has been studied by scientists since the Victorian era.

All three species were selected for the study because they each share similar colour patterns on their wings as a way to ward off predators.

The surprising finding, described in a paper published on 16 May in leading scientific journal Nature, is that the various species all look similar because they share the parts of their DNA that deal with colour patterns.

The genetic sharing between species, researchers believe, is the result of hybridisation. Considered extremely rare, particularly in animals, hybridisation occurs when insects of two different species interbreed in the wild.

The resulting hybrid offspring share traits with both mother and father. Though often considered an evolutionary dead-end, hybrids occasionally interbreed with a parent species, in the process introducing new genes that can help populations adapt to new or changing environments.

Professor Richard ffrench-Constant said: “The classical definition of a species is defined by two animals that can’t breed successfully. Here we have shown this definition to be faulty as rare matings can allow large sections of the genome to pass between species. This allows for useful traits such as colour patterns to be swapped wholesale between separate species. This changes the way we need to think about how species evolve.”

A total of 80 researchers in 32 research universities and institutions from eight countries worked on this genome project, while a subset of nine laboratories funded the sequencing of the 290 million DNA bases using new high-throughput technologies, allowing the work to proceed without major dedicated grant funding.

The nine laboratories that funded the sequencing work of the Heliconius Genome Consortium include:

  • University College London, UK, and Harvard University, USA: James Mallet
  • University of Exeter, UK: Richard ffrench-Constant
  • Harvard University, USA: Marcus Kronforst
  • Muséum National d’Histoire Naturelle, Paris, France: Mathieu Joron
  • Boston University, USA: Sean Mullen
  • University of California at Irvine, USA: Robert Reed, Adriana Briscoe
  • University of Edinburgh, UK: Mark Blaxter
  • Smithsonian Tropical Research Institute, Panama: W. Owen McMillan
  • Cambridge University, UK: Chris Jiggins

The study heralds a new era in genome biology, in which genome sequencing has become available to small groups of researchers for their own organism of choice.

04/09/2011 – Latest research featured in Nature video!


09/08/2011 – Latest research is published in Nature

Research reveals how butterflies copy their neighbours to fool birds

The mystery of how a butterfly has changed its wing patterns to mimic neighbouring species and avoid being eaten by birds has been solved by a team of European scientists. The study is published online on Sunday 14th August in the journal Nature.

The greatest evolutionary thinkers, including Wallace, Bates and Darwin, have all wondered how butterflies that taste bad to birds have evolved the same patterns of warning colouration. Now for the first time researchers led by the CNRS (Muséum National d’Histoire Naturelle, Paris) and the University of Exeter (UK) have shown how butterflies perform this amazing trick, known as ‘Müllerian mimicry’.

The study focused on the Amazonian species Heliconius numata, which mimics several other butterfly species at a single site in the rainforest. One population of Heliconius numata can therefore feature many distinct wing colour patterns resembling those of other butterflies, such as the Monarch’s relatives Melinaea, which are unpalatable to birds. This acts as a disguise, protecting them against predators.

The researchers located and sequenced the chromosomal region responsible for the wing patterns in H. numata. The butterfly’s wing-pattern variation is controlled by a single region on a single chromosome, containing several genes which control the different elements of the pattern. Known as a ‘supergene’, this clustering allows genetic combinations that are favoured for their mimetic resemblance to be maintained, while preventing combinations that produce non-mimetic patterns from arising. Supergenes are responsible for a wide range of what we see in nature: from the shape of primrose flowers to the colour and pattern of snail shells.

The researchers found that three versions of the same chromosome coexist in this species, each version controlling distinct wing-pattern forms. This has resulted in butterflies that look completely different from one another, despite having the same DNA. “We were blown away by what we found”, said Dr Mathieu Joron of the Muséum National d’Histoire Naturelle, who led the research. “These butterflies are the ‘transformers’ of the insect world. But instead of being able to turn from a car into a robot with the flick of switch, a single genetic switch allows these insects to morph into several different mimetic forms – it is amazing and the stuff of science fiction. Now we are starting to understand how this switch can have such a pervasive effect”.

Professor Richard ffrench-Constant of the University of Exeter added: “This phenomenon has puzzled scientists for centuries – including Darwin himself. Indeed, it was the original observations of mimicry that helped frame the concept of natural selection. Now that we have the right tools we are able to understand the reason for this amazing transformation: by changing just one gene, the butterfly is able to fool its predators by mimicking a range of different butterflies that taste bad.”

This single supergene also appears important in melanism in other species, including moths. In April 2011, a team led by Liverpool University explained in the journal Science how the Peppered Moth developed its black wings in nineteenth-century Britain’s sooty industrial environment.

“This supergene region not only allows insects to mimic each other, as in Heliconius, but also to mimic the soot blackened background of the industrial revolution – it’s a gene that really packs an evolutionary punch,” added Professor Richard ffrench-Constant.

 

13/06/11 – Two PhD Positions open to study butterflies and moths in the ffrench-Constant lab.

  1. Molecular basis of wing patterning in Heliconius butterflies: You will look atthe binding partners of transcription factors known to be involved in wingpatterning and colouration.
  2. Like moths to a flame: You will look at the impact of the roll out of new more powerful street lighting on moths and their bat predators.

Any enquiries can be directed straight to the Richard on rf222@exeter.ac.uk

 

 

25/03/2011  – Watch a video describing our research on beetle gut enzymes.


Funded Projects

We currently have 3 BBSRC funded research projects:

  • Candidate genes for Heliconius color pattern genes.  Click here for papers.
  • Rapid Virulence Annotation of bacterial genomes.    Click here for papers.
  • Mode of action of a novel bacterial toxin Mcf.            Click here for papers.

We currently have two EU funded research projects:

  • Making better antibiotic coatings with EMBEK1 consortium. Link

  • Drugs from bugs that kill bugs with GAMEXP consortium. Link

Heliconius Papers

  1. Characterization of a hotspot for mimicry: assembly of a butterfly wing transcriptome to genomic sequence at the HmYb/Sb locus.
  2. Genomic hotspots for adaptation: the population genetics of Müllerian mimicry in Heliconius erato.
  3. Genomic hotspots for adaptation: the population genetics of Müllerian mimicry in the Heliconius melpomene clade.
  4. Convergent evolution in the genetic basis of Müllerian mimicry in heliconius butterflies.
  5. Highly conserved gene order and numerous novel repetitive elements in genomic regions linked to wing pattern variation in Heliconius butterflies.
  6. A conserved supergene locus controls colour pattern diversity in Heliconius butterflies.

Bacterial virulence and RVA screening papers

  1. Rapid Virulence Annotation (RVA): identification of virulence factors using a bacterial genome library and multiple invertebrate hosts.
  2. The KdpD/KdpE two-component system of Photorhabdus asymbiotica promotes bacterial survival within M. sexta hemocytes.
  3. Genome-Wide Analysis Reveals Loci Encoding Anti-Macrophage Factors in the Human Pathogen Burkholderia pseudomallei K96243.

Mcf papers

  1. Insecticidal toxins from Photorhabdus bacteria and their potential use in agriculture.
  2. The insecticidal toxin Makes caterpillars floppy (Mcf) promotes apoptosis in mammalian cells.
  3. The insecticidal toxin makes caterpillars floppy 2 (Mcf2) shows similarity to HrmA, an avirulence protein from a plant pathogen.
  4. A single Photorhabdus gene, makes caterpillars floppy (mcf), allows Escherichia coli to persist within and kill insects.