̽��ֱ�� of Cambridge - Chris Jiggins

Exceptional scientists elected as Fellows of the Royal Society 2023

lw355 — Wed, 10 May 2023 10:52:57 +0000

̽��ֱ��Royal Society is a self-governing Fellowship of many of the world’s most distinguished scientists drawn from all areas of science, engineering and medicine.

̽��ֱ��Society’s fundamental purpose, as it has been since its foundation in 1660, is to recognise, promote and support excellence in science and to encourage the development and use of science for the benefit of humanity.

This year, a total of 80 researchers, innovators and communicators from around the world have been elected as Fellows of the Royal Society for their substantial contribution to the advancement of science. These include 59 Fellows, 19 Foreign Members and two Honorary Fellows.

Sir Adrian Smith, President of the Royal Society said: “I am delighted to welcome our newest cohort of Fellows. These individuals have pushed forward the boundaries of their respective fields and had a beneficial influence on the world beyond. This year’s intake have already achieved incredible things, and I have no doubt that they will continue to do so. I look forward to meeting them and following their contributions in future.”

̽��ֱ��Fellows and Foreign Members join the ranks of Stephen Hawking, Isaac Newton, Charles Darwin, Albert Einstein, Lise Meitner, Subrahmanyan Chandrasekhar and Dorothy Hodgkin.

̽��ֱ��Cambridge Fellows are:

Professor Cathie Clarke FRS

Professor of Theoretical Astrophysics, Institute of Astronomy, and Fellow of Clare College

Clarke studies astrophysical fluid dynamics, including accretion and protoplanetary discs and stellar winds. She was the first to demonstrate how protoplanetary disc formation around low-mass young stars is determined by their radiation field. In 2017 she became the first woman to be awarded the Eddington Medal by the Royal Astronomical Society and in 2022 she became director of the Institute of Astronomy.

She said: “It's a great honour to join the many Cambridge astrophysicists who have held this title. I would like to particularly pay tribute to the many junior colleagues, PhD students and postdocs who have contributed to my research.”

Professor Christopher Jiggins FRS

Professor of Evolutionary Biology (2014), Department of Zoology, and Fellow of St John's College

Jiggins studies adaption and speciation in the Lepidoptera (butterflies and moths). In particular he is interested in studying how species converge due to mimicry as a model for understanding the predictability of evolution and the genetic and ecological causes of speciation. He demonstrated the importance of hybridisation and movement of genes between species in generating novel adaptations. He also works on the agricultural pest cotton bollworm and carries out genomic studies of the insect bioconversion species, black soldier fly.

He said: “I am amazed and delighted to receive this honour, and would thank all the amazing students, and postdocs that I have been lucky enough to work with over the years.”

Dr Philip Jones FRS

Senior Group Leader, Wellcome Sanger Institute and Professor of Cancer Development, ̽��ֱ�� of Cambridge, and Fellow of Clare College

Jones studies how normal cell behaviour is altered by mutation in aging and the earliest stages of cancer development. He focuses on normal skin and oesophagus, which become a patchwork of mutant cells by middle age. He has found that different mutations can either promote or inhibit cancer development giving hope of new ways to prevent cancer in the future. He is also a Consultant in Medical Oncology at Addenbrooke’s Hospital in Cambridge.

He said: “I am delighted to be elected to the Fellowship of the Royal Society. This honour is a tribute to the dedication of my research team and collaborators and support of my mentors and scientific colleagues over many years.”

Dr Lori Passmore FRS

Group Leader, Structural Studies Division, MRC Laboratory of Molecular Biology, and Fellow of Clare Hall

Passmore a cryo-electron microscopist and structural biologist who works at the Medical Research Council (MRC) Laboratory of Molecular Biology and at the ̽��ֱ�� of Cambridge. She is known for her work on multiprotein complexes involved in gene expression and the development of new supports for cryo-EM studies. She also studies the molecular mechanisms underlying Fanconi anemia, a rare genetic disease resulting in an impaired response to DNA damage.

She said: “I am so honoured to be recognised alongside such an exceptional group of scientists. I am grateful to all the trainees, collaborators and colleagues whom I have worked with over the past years - science is truly collaborative and this is a recognition of all the courageous work of many people.”

Professor Peter Sewell FRS

Professor of Computer Science, Department of Computer Science and Technology, and Fellow of Wolfson College

Sewell’s research aims to put the engineering of the real-world computer systems that we all depend on onto better foundations, developing techniques to make systems that are better-understood, more robust and more secure. He and his group are best known for their work on the subtle relaxed-memory concurrency behaviour and detailed sequential semantics of processors and programming languages. He co-leads the CHERI cybersecurity project, for which his team have established mathematically-proven security properties of Arm's Morello industrial prototype architecture.

He said: “This honour is a testament to the work of many excellent colleagues over the years, without whom none of this would have been possible.”

Professor Ivan Smith FRS

Professor of Geometry, Centre for Mathematical Sciences, and Fellow of Caius College

Smith is a mathematician who deals with symplectic manifolds and their interaction with algebraic geometry, low-dimensional topology and dynamics. In 2007, he received the Whitehead Prize for his work in symplectic topology, highlighting the breadth of applied techniques from algebraic geometry and topology, and in 2013 the Adams Prize.

He said: “I am surprised, delighted and hugely honoured to be elected a Fellow of the Royal Society. I’ve been very fortunate to work in a rapidly advancing field, learning it alongside many inspirational and generous collaborators, who should definitely share this recognition.”

Professor William Sutherland CBE FRS

Miriam Rothschild Chair of Conservation Biology, Department of Zoology and Professorial Fellow of St Catharine’s College

Sutherland is a conservation scientist who is interested in improving the processes by which decisions are made. This has involved horizon scanning to identify future issues to reduce the surprises of future developments. His main work has been the industrial-scale collation of evidence to determine which interventions are effective and which are not and then establishing processes for embedding evidence in decision making. He has developed a free, online resource, Conservation Evidence, summarising evidence for the effectiveness of conservation actions to support anyone making decisions about how to maintain and restore biodiversity and an open access book Transforming Conservation: a practical guide to evidence and decision making.

He said: “I am delighted that our work on the means of improving decision making in conservation and elsewhere has been recognised in this way and thank my numerous collaborators.”

Seven outstanding Cambridge researchers have been elected as Fellows of the Royal Society, the UK’s national academy of sciences and the oldest science academy in continuous existence.

These individuals have pushed forward the boundaries of their respective fields and had a beneficial influence on the world beyond

Sir Adrian Smith, President of the Royal Society

Courtesy of ̽��ֱ��Royal Society

̽��ֱ��Royal Society, London

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Male butterflies mark their mates with a repulsive smell during sex to ‘turn off’ other suitors

jg533 — Tue, 19 Jan 2021 19:00:00 +0000

Led by Professor Chris Jiggins in the ̽��ֱ�� of Cambridge's Department of Zoology, the team mapped production of the scented chemical compound to the genome of a species of butterfly called Heliconius melponene, and discovered a new gene. They also discovered that the chemical, made in the sex glands of the males, is identical to a chemical produced by flowers to attract butterflies. ̽��ֱ��study, published today in the journal PLOS Biology, shows that butterflies and flowers independently evolved to make the same chemical for different purposes.

Dr Kathy Darragh, lead author of the paper and previously a member of Jiggins' research group, said: “We identified the gene responsible for producing this powerful anti-aphrodisiac pheromone called ocimene in the genitals of male butterflies. This shows that the evolution of ocimene production in male butterflies is independent of the evolution of ocimene production in plants.

“For a long time it was thought insects took the chemical compounds from plants and then used them, but we have shown butterflies can make the chemicals themselves – but with very different intentions. Male butterflies use it to repulse competitors and flowers use the same smell to entice butterflies for pollination.”

There are around 20,000 species of butterflies worldwide. Some only live for a month, but the Heliconius melponene butterflies found in Panama that were studied live for around six months. ̽��ֱ��females typically have few sexual partners and they store the sperm and use it to fertilise their eggs over a number of months after a single mating.

Male butterflies have as many mates as they can and each time they transfer the anti-aphrodisiac chemical because they want to be the one to fertilise the offspring. This chemical, however, is not produced by all Heliconius butterflies. Whilst Heliconius melpomene does produce ocimene, another closely related species that was analysed – Heliconius cydno – does not produce the strong smelling pheromone.

If the smell has such a powerful effect, how do the butterflies know when to be attracted or when to steer clear?

Darragh, now based at the ̽��ֱ�� of California, Davis, explained: “ ̽��ֱ��visual cues the butterflies get will be important – when the scent is detected in the presence of flowers it will be attractive but when it is found on another butterfly it is repulsive to the males – context is key.”

This new analysis of the power of smell – also called chemical signalling - sheds new light on the importance of scent as a form of communication.

Jiggins said: “ ̽��ֱ��butterflies presumably adapted to detect this chemical to find flowers, and then evolved to use it in this very different way. ̽��ֱ��males want to pass their genes onto the next generation and they don’t want the females to have babies with other fathers, so they use this scent to make them unsexy.

“Male butterflies pester the females a lot so it might benefit the females too if the smell left behind means they stop being bothered for sex after they have already mated.”

Reference

Darragh, K. et al. 'A novel terpene synthase controls differences in anti-aphrodisiac pheromone production between closely related Heliconius butterflies.' Jan 2021, PLOS Biology. DOI: 10.1371/journal.pbio.3001022

Adapted from a press release by St John's College, Cambridge

Butterflies have evolved to produce a strongly scented chemical in their genitals, which they leave behind after sex to deter other males from pursuing their mates.

̽��ֱ��males want to pass their genes onto the next generation, and they don’t want the females to have babies with other fathers so they use this scent to make them unsexy.

Chris Jiggins

Luca Livraghi

Two butterflies mating in captivity. Heliconius cydno (left) and Heliconius melpomene (right).

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Butterflies are genetically wired to choose a mate that looks just like them

ta385 — Fri, 08 Feb 2019 10:35:48 +0000

A team of academics from the ̽��ֱ�� of Cambridge, in collaboration with the Smithsonian Tropical Research Institute in Panama, observed the courtship rituals and sequenced the DNA from nearly 300 butterflies to find out how much of the genome was responsible for their mating behaviour.

̽��ֱ��research, published in PLOS Biology, is one of the first ever genome studies to look at butterfly behaviour and it unlocks the secrets of evolution to help explain how new species are formed. Scientists sequenced the DNA from two different species of Heliconius butterflies which live either side of the Andes mountains in Colombia. Heliconians have evolved to produce their own cyanide which makes them highly poisonous and they have distinct and brightly coloured wings which act as a warning to would-be predators.

Professor Chris Jiggins, one of the lead authors on the paper and a Fellow of St John’s College, said: “There has previously been lots of research done on finding genes for things like colour patterns on the butterfly wing, but it’s been more difficult to locate the genes that underlie changes in behaviour. What we found was surprisingly simple – three regions of the genome explain a lot of their behaviours. There’s a small region of the genome that has some very big effects.”

̽��ֱ��male butterflies were introduced to female butterflies of two species and were scored for their levels of sexual interest directed towards each. ̽��ֱ��scientists rated each session based on the number of minutes of courtship by the male – shown by sustained hovering near or actively chasing the females.

Unlike many butterflies which use scented chemical signals to identify a mate, Heliconians use their long-range vision to locate the females, which is why it’s important each species has distinct wing markings. When a hybrid between the two species was introduced, the male would most commonly show a preference for a mate with similar markings to itself. ̽��ֱ��research showed the same area of the genome that controlled the coloration of the wings was responsible for defining a sexual preference for those same wing patterns.

Dr Richard Merrill, one of the authors of the paper, based at Ludwig-Maximilians-Universität, Munich, said: “It explains why hybrid butterflies are so rare – there is a strong genetic preference for similar partners which mostly stops inter-species breeding. This genetic structure promotes long-term evolution of new species by reducing intermixing with others.”

̽��ֱ��paper is one of two published in PLOS Biology and funded by the European Research Council which brought together ten years of research by Professor Jiggins and his team. ̽��ֱ��second study investigated how factors including mate preference act to prevent genetic mixing between the same two species of butterfly. They discovered that despite the rarity of hybrid butterflies – as a result of their reluctance to mate with one another – a surprisingly large amount of DNA has been shared between the species through hybridisation. There has been ten times more sharing between these butterfly species than occurred between Neanderthals and humans.

Dr Simon Martin, one of the authors of the second paper, from the ̽��ֱ�� of Edinburgh, explained: “Over a million years a very small number of hybrids in a generation is enough to significantly reshape the genomes of the these butterflies.”

Despite this genetic mixing, the distinct appearance and behaviours of the two species remain intact, and have not become blended. ̽��ֱ��researchers found that there are many areas of the genome that define each species, and these are maintained by natural selection, which weeds out the foreign genes. In particular, the part of the genome that defines the sex of the butterflies is protected from the effects of inter-species mating. As with the genetics that control mating behaviour, these genes enable each butterfly type to maintain its distinctiveness and help ensure long-term survival of the species. But can the findings translate into other species including humans?

Professor Jiggins said: “In terms of behaviour, humans are unique in their capacity for learning and cultural changes but our behaviour is also influenced by our genes. Studies of simpler organisms such as butterflies can shed light on how our own behaviour has evolved. Some of the patterns of gene sharing we see between the butterflies have also been documented in comparisons of the human and Neanderthal genomes, so there is another link to our own evolution.”

“Next we would like to know how novel behaviour can arise and what kind of genetic changes you need to alter behaviour. We already know that you can make different wing patterns by editing the genes. These studies suggest that potentially new behaviours could come about by putting different genes together in new combinations.”

References

Martin, S et al. Recombination rate variation shapes barriers to introgression across butterfly genomes. PLOS Biology; 7 Feb 2019; DOI: 10.1371/journal.pbio.2006288

Merrill, R et al. Genetic dissection of assortative mating behavior. PLOS Biology; 7 Feb 2019; DOI: 10.1371/journal.pbio.2005902

Male butterflies have genes which give them a sexual preference for a partner with a similar appearance to themselves, according to new research.

There’s a small region of the genome that has some very big effects

Chris Jiggins

Heliconius melpomene amaryllis

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Celebrating 10 years of European research excellence

ag236 — Mon, 13 Mar 2017 12:40:43 +0000

When European government representatives met in Lisbon in the year 2000, and expressed an aspiration that Europe should become the world's leading knowledge economy by 2010, they agreed on the need to create a body to “fund and co-ordinate basic research at European level”.

This was the impetus underlying the creation, in 2007, of the European Research Council (ERC).

Ten years after its foundation, the ERC has become a European success story. It has supported some 6,500 projects through its prestigious grants, and has become a unique model for the fostering and funding of innovative academic research.

To mark the anniversary, events are being held across Europe during ERC Week, running from 13-19 March. At the ̽��ֱ�� of Cambridge, various recipients of ERC grants will be sharing their findings with a wide audience in talks scheduled as part of the Cambridge Science Festival.

̽��ֱ��McDonald Institute for Archaeological Research will be joining in ERC Week celebrations by hosting a conference on Thursday, 16 March.

On the same day, a reception for Cambridge recipients of ERC grants, attended by ERC president Prof. Jean-Pierre Bourguignon, will be held at the Fitzwilliam Museum, which is currently showing the ERC-supported exhibition, “Madonnas and Miracles: ̽��ֱ��Holy Home in Renaissance Italy”.

̽��ֱ��ERC supports outstanding researchers in all fields of science and scholarship. It awards three types of research awards (Starter, Consolidator, Advanced) through a competitive, peer-reviewed process that rewards excellence. Its focus on “frontier research” allows academics to develop innovative and far-reaching projects over five-year periods.

̽��ֱ��United Kingdom has been the largest recipient of ERC awards –between 2007 and 2015, it received 24% of all ERC funding.

To date, the ERC has supported 1524 projects by UK-based academics. Researchers at the ̽��ֱ�� of Cambridge have won 218 of those grants, in fields ranging from Astronomy to Zoology.

“What is special about an ERC grant?”, asks Dr Marta Mirazón Lahr, who was awarded an ERC Advanced Investigator Award for her project “IN-AFRICA”, which examines the evolution of modern humans in East Africa.

“An obvious side is that it’s a lot of money. But I think it’s more than just the money. Because it’s five years, the ERC grant allows you to get a group and build a real community around the project. It also allows you to explore things in greater depth.”

An ERC grant allowed Dr Debora Sijacki, at the Institute of Astronomy, to attract “a really competitive and international team, which otherwise would have been almost impossible to get.”

Being funded for a five-year period, she adds, “gives you time to expand and really tackle some of the major problems in astrophysics, rather than doing incremental research.”

It also allowed her access to facilities: “In my case, it was access to world-leading supercomputers. And without the ERC grant this would have been difficult.”

“Real progress in research is made when researchers can tackle big important questions," says Prof David Baulcombe, of the Department of Plant Sciences, the recipient of two ERC grants. " ̽��ֱ��ERC programme invites researchers to submit ambitious, blue-skies, imaginative proposals. There aren’t many others sources of funding that allow one to do that sort a thing.”

Dr Christos Lynteris, of the Centre for Research in the Arts, Humanities and Social Sciences (CRASSH), is the recipient of an ERC Starting Grant for his project “Visual representations of the third plague pandemic.

“An ERC is a unique opportunity," he says: “it fosters interdisciplinary work. It also fosters analytical tools and the creation of new methods.”

“It offers a great opportunity to work with other people, over a period of 5 years, which is something very unusual, and with quite a liberal framework, so you are able to change and shift your questions, to reformulate them. For me, it means freedom, above everything.”

For Prof. Ottoline Leyser, Director of the Sainsbury Laboratory, it is the “ERC ethos” and its “emphasis on taking things in new directions” that has made all the difference.

̽��ֱ��ERC values an innovative, risk-taking approach “in a way that conventional grant-funding schemes don’t –they usually want to see that slow build rather than the risky step into the unknown.”

Prof. Simon Goldhill, Director of CRASSH, was awarded an ERC Advanced Investigator Award for his project “Bible and Antiquity in 19th Century Culture”. It has given him “the unique opportunity to do a genuinely interdisciplinary collaborative project with the time and space it takes to make such interdisciplinarity work.”

“Most importantly,” he adds, “the financial model offered by this sort of project enables us to do work that is 15 or 20 years ahead of the rest of the world, and Britain and Europe are all the stronger for it.”

̽��ֱ��sentiment is echoed by Prof. Ruth Cameron, of the Department of Materials Science and Metallurgy. ̽��ֱ��impact of an ERC grant for her project “3D Engineered Environments for Regenerative Medicine” has, she says, “exceeded expectations”.

So what has the ERC ever done for us? Quite a lot, say Cambridge academics, as they mark the 10th anniversary of Europe’s premier research-funding body

̽��ֱ��financial model offered by this sort of project enables us to do work that is 15 or 20 years ahead of the rest of the world. Britain and Europe are all the stronger for it.

Prof. Simon Goldhill, CRASSH

Cambridge & the ERC: 10 years of research excellence

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Genetic switch that turned moths black also colours butterflies

tdk25 — Thu, 02 Jun 2016 04:00:22 +0000

̽��ֱ��same gene that enables tropical butterflies to mimic each other’s bright and colourful patterning also caused British moths to turn black amid the grime of the industrial revolution, researchers have found.

Writing in the journal Nature, a team of researchers led by academics at the Universities of Cambridge and Sheffield, report that a fast-evolving gene known as “cortex” appears to play a critical role in dictating the colours and patterns on butterfly wings.

A parallel paper in the same journal by researchers from the ̽��ֱ�� of Liverpool shows that this same gene also caused the peppered moth to turn black during the mid-19th century, when it evolved to find new ways to camouflage itself; a side-effect of industrial pollution at the time.

̽��ֱ��finding offers clues about how genetics plays a role in making evolution a predictable process. For reasons the researchers have yet to understand in full, the cortex gene, which helps to regulate cell division in butterflies and moths, has become a major target for natural selection acting on colour and pattern on the wings.

Chris Jiggins, Professor of Evolutionary Biology and a Fellow of St John’s College, ̽��ֱ�� of Cambridge, said: “What’s exciting is that it turns out to be the same gene in both cases. For the moths, the dark colouration developed because they were trying to hide, but the butterflies use bright colours to advertise their toxicity to predators. It raises the question that given the diversity in butterflies and moths, and the hundreds of genes involved in making a wing, why is it this one every time?”

Dr Nicola Nadeau, a NERC Research Fellow from the ̽��ֱ�� of Sheffield added: “It’s amazing that the same gene controls such a diversity of different colours and patterns in butterflies and a moth. Our study, together with the findings from the ̽��ֱ�� of Liverpool, shows that the cortex gene is important for colour and pattern evolution in this whole group of insects.”

Butterflies and moths comprise the order of insects known as Lepidoptera. Nearly all of the 160,000 types of moth and 17,000 types of butterfly have different wing patterns, which are adapted for purposes like attracting mates, giving off warnings, camouflage (also known as “crypsis”), and thermal regulation.

These wing patterns are actually made up of tiny coloured scales arranged like tiles on a roof. Although they have been studied by biologists for over a century, the molecular mechanisms which control their development are only now starting to be uncovered.

̽��ֱ��peppered moth is one of the most famous examples of evolution by natural selection. Until the 19th Century, peppered moths were predominantly pale-coloured, and used this to camouflage themselves against lichen-covered tree trunks, which made them almost invisible to predators.

During the industrial revolution, however, the lichen on trees in some parts of the country was killed by pollution, and soot turned the trunks black. A corresponding change was seen in the in peppered moths which turned black as well, helping them to remain camouflaged from birds. ̽��ֱ��process is known as industrial melanism – melanism meaning the development of dark coloured pigmentation.

̽��ֱ��Liverpool-led team found that this colour change was produced by a mutation in the cortex gene, which occurred during the mid 1800s, just before the first reported sighting of black peppered moths. Fascinatingly, however, the Cambridge-Sheffield study has now shown that exactly the same gene also influences the extremely bright and colourful patterns of Heliconius – the name given to about 40 different closely-related species of beautiful, tropical butterflies found in South America.

Heliconius colour patterns are used to send a signal to potential predators that the butterflies are toxic if eaten, and different types of Heliconius butterfly mimic one another by using their bright colours as warning signals. Unlike the dark colouring of the peppered moth, it is therefore an evolutionary development that is meant to be seen.

̽��ֱ��researchers carried out fine-scale mapping, looking for parts of the DNA sequence that were specifically different in butterflies with different patterns, in three different Heliconius species, and in each case the cortex gene was found to be responsible for this adaptation in their patterning.

Because Heliconius species are extremely diverse, the study of what causes variations in their patterning can provide more general clues about the genetic switches that control diversification in species.

In most cases, the genes responsible for these processes are known as “transcription factors” – meaning that they are responsible for turning other genes on and off. Intriguingly, what made cortex such an elusive switch to spot was the fact that it does not do this. Instead, it is a cell cycle regulator, which means that it controls when cells divide and thus when different coloured scales develop within a butterfly wing.

“It’s a different gene to the one we might have expected and we still need to do more to understand exactly what it’s doing, and how it’s doing it,” Jiggins said. Dr Nadeau added “Our results are even more surprising because the cortex gene was previously thought to only be involved in producing egg cells in female insects, and is very similar to a gene that controls cell division in everything from yeast to humans.”

Reference

Nadeau N. et al. ̽��ֱ��gene cortex controls mimicry and crypsis in butterflies and moths. Nature, 2 June 2016; DOI: 10.1038/nature17961

Additional image: ̽��ֱ��study reveals that the black colour of the moth (above) and the yellow patches on the butterfly (below) were caused by the same gene, known as “cortex”. Credits: Yikrazuul and Loz, both via Wikimedia Commons.

Heliconius butterflies have evolved bright yellow colours to deter predators, while peppered moths famously turned black to hide from birds. A new study reveals that the same gene causes both, raising fascinating questions about how evolution by natural selection occurs in these species.

It raises the question that given the diversity in butterflies and moths, and the hundreds of genes involved in making a wing, why is it this one every time?

Chris Jiggins

Chris Jiggins, ̽��ֱ�� of Cambridge

Heliconius Melpomene.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Genetic ‘paint box’ shuffled between butterfly species to create new wing patterns

fpjl2 — Fri, 15 Jan 2016 19:01:08 +0000

New research on butterfly genomes has revealed that the genetic components that produce different splotches of colour on wings can be mixed up between species by interbreeding to create new patterns, like a "genetic paint box".

Research on Amazonian Heliconius butterflies has shown that two of the most common colour patterns, found in combination on the wings of many Heliconius species – the dennis red patch on the base of the forewing, and the ray red streaks that fan out across the hindwing – are controlled by separate genetic switches that arose in completely different species.

A team of researchers has traced the merging of these two wing pattern elements to interbreeding between butterfly species that occurred almost two million years ago.

It has been known for some time that exchange of genes between species can be important for evolution: humans have exchanged genes with our now extinct relatives which may help survival at high altitudes, and Darwin's Finches have exchanged a gene that influences beak shape. In butterflies, the swapping of wing pattern elements allows different species to share common warning signs that ward off predators – a phenomenon known as mimicry.

However, the new study, published today in the journal PLOS Biology, is the first to show such mixing of genetic material can produce entirely new wing patterns, by generating new combinations of genes.

"We found that different colour patches on the wings are controlled by different genetic switches that can be turned on and off independently. As these switches were shared between species they got jumbled up into different combinations, making new wing patterns," said senior author Professor Chris Jiggins, from Cambridge ̽��ֱ��'s Department of Zoology.

̽��ֱ��researchers sequenced the genomes from 142 individual butterflies across 17 Heliconius species and compared the DNA data, focusing on the regions associated with the two red colour patterns of dennis and ray on the forewing and hindwing. "In each butterfly genome, we narrowed down around 300 million base pairs of DNA to just a few thousand," said Jiggins.

They found that the genetic switches for these distinct wing splotches operated independently, despite being located next to each other in the genome. ̽��ֱ��sequencing revealed that the switch for each colour splotch had evolved just once, and in separate species, but had been repeatedly shared across all the Heliconius species at occasional points of interbreeding dating back almost two million years.

"By identifying the genetic switches associated with bits of wing pattern, when they evolved and how they diverged, we can actually map onto the species tree how these little regions of colour have jumped between species - and we can see they are jumping about all over the place," said Jiggins.

̽��ֱ��key to this evolutionary butterfly painting is the independence of each genetic switch. " ̽��ֱ��gene that these switches are controlling is identical in all these butterflies, it is coding for the same protein each time. That can't change as the gene is doing other important things," said lead author Dr Richard Wallbank, also from Cambridge's Department of Zoology.

"It is the switches that are independent, which is much more subtle and powerful, allowing evolutionary tinkering with the wing pattern without affecting parts of the genetic software that control the brain or eyes.

"This modularity means switching on a tiny piece of the gene's DNA produces one piece of pattern or another on the wings – like a genetic paint box," Wallbank said.

Reference:
Wallbank RWR, Baxter SW, Pardo-Diaz C, Hanly JJ, Martin SH, Mallet J, et al. (2016) Evolutionary Novelty in a Butterfly Wing Pattern through Enhancer Shuffling. PLoS Biol 14(1): e1002353. doi:10.1371/journal.pbio.1002353

Research finds independent genetic switches control different splotches of colour and pattern on Heliconius butterfly wings, and that these switches have been shared between species over millions of years, becoming “jumbled up” to create new and diverse wing displays.

We can actually map onto the species tree how these little regions of colour have jumped between species

Chris Jiggins

Jiggins group

A range of wing patterns across Heleconius butterfly species.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

How the butterflies got their spots

bjb42 — Thu, 04 Feb 2010 00:00:00 +0000

Heliconius, or passion-vine butterflies, live in the Americas - from the southern United States to southern South America. Although they cannot interbreed, H. melpomene and H. erato have evolved to mimic one another perfectly.

These delicate butterflies have splashes of red and yellow on their black wings, signaling to birds that they contain toxins and are extremely unpalatable. They mimic one another's colour and pattern to reinforce these warning signals.

Scientists have studied these butterflies since the 1860s as a classic case of evolution in action, but only now is modern sequencing technology unlocking the underlying genetics.

̽��ֱ��Cambridge-led team of researchers from UK and US universities, which has been breeding the butterflies in Panama for the past decade, has been searching for the genes responsible for the butterflies' wing patterns and the answer to the question of whether the same genes in two different species are responsible for the mimicry.

According to Dr Chris Jiggins of the Department of Zoology at the ̽��ֱ�� of Cambridge, one of the authors of the study: " ̽��ֱ��mimicry is remarkable. ̽��ֱ��two species that we study - erato and melpomene - are quite distantly related, yet you can't tell them apart until you get them in your hand. ̽��ֱ��similarity is incredible - even down to the spots on the body and the minute details of the wing pattern."

That the two species have evolved to look exactly the same is due to predation by birds. " ̽��ֱ��birds will try anything that looks different in the hope that it's good, so they learn that certain wing patterns are unpalatable and avoid them, but anything that deviates slightly from what they've experienced before is more likely to be attacked," he explains.

These butterflies have been studied since Darwin's day because they are such a striking example of adaptation. For years, scientists have pondered whether when different species evolve to look the same, they share a common genetic mechanism.

According to Jiggins: "It's interesting because it tells us how flexible evolution is. If you get the same wing pattern evolving independently in different populations, do you expect the same genes to be involved?"

Because there are thousands of genes in the butterflies' genome, most scientists felt it was unlikely that the same genes should be involved. But the results of this study suggest that this is, in fact, the case.

̽��ֱ��new results - published today in two parallel papers in the journal PLoS Genetics - show that the regions of the genome associated with the wing patterns are very small - akin to genetic "hotspots".

"This tells us something about the limitations on evolution, and how predictable it is. Our results imply that despite the many thousands of genes in the genome there are only one or two that are useful for changing this colour pattern. It seems like evolution might be concentrated in quite small regions of the genome - or hotspots - while the rest of it does not change very much," says Jiggins.

This is not the only unexpected element of the study. ̽��ֱ��team was also surprised that the obvious candidate genes - such as those involved in colour or wing pattern in other species - do not seem to be involved in the passion-vine butterflies' mimicry.

According to Jiggins: "We think it's more likely to be some novel method of cellular signaling, which is quite intriguing and could be important in many other insect species."

̽��ֱ��next stage of the research is to look at other traits, such as behaviour, because the butterflies have preferences for particular colours and use wing patterns to select mates. "It seems the same regions of the genome control this behaviour as well as the wing pattern. We'd like to understand this," he says.

̽��ֱ��results are published in PLoS Genetics on 5 February 2010.

How two butterfly species have evolved exactly the same striking wing colour and pattern has intrigued biologists since Darwin's day. Now, scientists at Cambridge have found "hotspots" in the butterflies' genes that they believe will explain one of the most extraordinary examples of mimicry in the natural world.

It's interesting because it tells us how flexible evolution is.

Dr Chris Jiggins

whologwhy from Flickr

BUTTERFLY

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On the wings of a butterfly

bjb42 — Fri, 01 May 2009 15:16:36 +0000

On reading Henry Walter Bates’ 1862 account of his travels in the Amazon, Charles Darwin was captivated not only by Bates’ description of the stunning diversity of butterfly species and wing patterns found in the Amazonian jungle, but also by the impressive mimicry between unrelated species. Darwin wrote: ‘It is hardly an exaggeration to say, that whilst reading and reflecting on the various facts given in this Memoir, we feel to be as near witnesses, as we can ever hope to be, of the creation of a new species on this earth.’¹

Bates hypothesised that mimicry evolved to confuse predators. Edible butterflies, for instance, copied the wing patterns of toxic species so that predators would avoid eating them. He also described what looked like evolution in action: he observed a continuum, from variable species, in which different wing patterns were found together in the same locality, through to related species with different wing patterns. Now, 150 years later, modern science has taken this to another level, with new research that aims to study the predictability of evolution by revealing the genetic basis of wing pattern mimicry.

̽��ֱ��importance of pattern

We now recognise that not only do edible species mimic nasty ones (today called Batesian mimicry), but that several nasty species can also benefit from mimicking one another (Müllerian mimicry) – bees and wasps being a familiar example. Many of the Amazonian butterflies described by Bates are in fact Müllerian mimics, and the best-studied group are the genus Heliconius, the passion vine butterflies. Work by Dr Chris Jiggins’ group in the Department of Zoology has focused on Heliconius butterflies as a case study in evolutionary biology.

By testing the role of Heliconius wing patterns in the wild, Dr Jiggins and others have confirmed Bates’ hunch: changes in wing pattern play a big role in determining how successful the butterflies are in both mating and avoiding being eaten. Using flapping models with different patterns, the researchers have shown that the butterflies choose to mate with individuals that look the same as themselves; because of this, over time, different patterns are likely to split into new species. In addition, hybrids between populations with different patterns have intermediate patterns that are not recognised by predators as harmful and therefore suffer disproportionately from attacks, reinforcing the split into new species.

This dual role of wing patterns in signalling both to predators and to potential mates makes pattern a ‘key trait’ for speciation. As Bates suggested, shifts in wing patterns do indeed lead to the evolution of new species.

Selection signatures

One of the current hot topics in evolutionary biology is to what extent we can predict the genetic path of evolution. One particular Heliconius species (Heliconius melpomene) is an ideal system in which to address this question because it has many geographic populations with very different colour patterns.

A major new project focusing on the genetic basis of wing patterns has commenced in the Jiggins lab with funding from the Biotechnology and Biological Sciences Research Council (BBSRC), Royal Society, Leverhulme Trust and Natural Environment Research Council (NERC).

Over the past decade, the researchers have been collecting different forms of H. melpomene from around South America, carrying out genetic crosses at a field station in Panama. These crosses have shown that dramatic differences in colour pattern are controlled by just a handful of genes and that these genes are clustered together on four out of the 21 Heliconius chromosomes. ̽��ֱ��genes act as wing pattern ‘switches’, turning on and off the presence of major pattern elements, such as a large red forewing band. ̽��ֱ��challenge is to find out precisely what these genes are and how they work.

In collaboration with the Wellcome Trust Sanger Institute, regions of the butterfly genome are being sequenced to identify the specific nature of the pattern switches. ̽��ֱ��expectation was that the switches would correspond to well-known genes, perhaps controlling wing development or colour pigments. In fact, the two genomic regions studied so far each contains around 20 genes, none of which is known for its involvement in these processes. This is in itself exciting as it implies that novel mechanisms of pattern determination are operating; current research is focused on determining which, of all these genes, are having an effect in the butterfly.

Genetics of mimicry

What attracted Darwin and others to mimicry as a case study in evolution is its repeatability – the same patterns evolve in distantly related species. A key question for an evolutionary geneticist is therefore whether the patterns are generated by the same genetic mechanisms, or different ones. Again, Heliconius butterflies are a good system to study this.

Heliconius melpomene co-mimics another species, Heliconius erato, all over the neotropics – in any location you care to look you will find that the two species have evolved identical patterns. Recently, in collaboration with research groups in the USA, it has been shown that pattern switches in the two species are controlled by the same regions of DNA, such that genes at identical locations in the genome code for either a red forewing band or a yellow hindwing bar. This implies that evolution of the same mimicry patterns in the two species has been made easier by a shared genetic system. While predation against abnormal wing patterns drives the evolution of mimicry through Darwinian natural selection, a shared developmental system may bias the raw materials in favour of certain kinds of patterns.

Of course, the link between wing pattern adaptation and speciation requires changes in behaviour. ̽��ֱ��mating preferences of divergent populations need to evolve in order to match their wing patterns. Remarkably, crossing experiments currently being carried out in Panama show that the genes underlying these changes in behaviour are closely associated with colour pattern genes. It seems that there are ‘hot spots’ in the genome for evolutionary change, influencing traits as diverse as wing patterns and mating preference.

An enduring example

It is an exciting time to be studying butterfly mimicry. ̽��ֱ��combination of population genetic, developmental and behavioural approaches is starting to answer the issues Darwin and Bates themselves debated – questions that were posed at the very dawn of evolutionary biology. Throughout the intervening decades, Heliconius butterflies have persisted as an example of evolution in action. With the imminent sequencing of the Heliconius melpomene genome, they will no doubt continue to be so for some time yet. Charles Darwin would surely have approved.

¹_{[Darwin, C.R.] 1863. [Review of] Contributions to an insect fauna of the Amazon Valley. By Henry Walter Bates, Esq. Transact. Linnean Soc. Vol. XXIII. 1862, p. 495. Natural History Review 3, 219–224.}

For more information, please contact the author Dr Chris Jiggins (c.jiggins@zoo.cam.ac.uk) at the Department of Zoology.

Since Darwin’s time, Amazonian butterflies have intrigued biologists as examples of evolution in action.

One of the current hot topics in evolutionary biology is to what extent we can predict the genetic path of evolution.

Dr Mathieu Joron

Heliconius melpomene

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