Reporter news

Subscribe to RSS feed

News archive

Media relations

Darwin - past, present and future

As the 150th anniversary of the publication of Darwin’s On the Origin of Species draws to a close, his work is still prompting intellectual debate and research.

Here we look at three very different ways in which the University is drawing on Darwin's legacy to gain a more complete understanding of the man and the implications of his theory.

Specialisation in speciation
A long-term study of periwinkles - snails that live in the intertidal zone, the area that's exposed at low tide and underwater at high tide - is providing a Leeds academic with a real-life example of Darwinism in action.

"I'm seeking to find out not only the mechanisms but also the genes that cause speciation, the evolutionary process through which new biological species come about," explains John Grahame, Biological Sciences.

"Not many people persist for so long with a study of one group, but I realised that periwinkles were very much the kind of organism that was likely to be relevant to questions of speciation. These snails are very local breeders so there's opportunity for local selection to take place."

Working on two coastal sites in Yorkshire, John and his team collect the snails, sorting, identifying, recording shell images and analysing their shapes. "We found that within one species there's a 'break' in form. What we previously thought were just straightforward variations in shell and body form were actually signalling a partial reproductive barrier - a block to gene flow - so the snails aren't totally free to mate.  This realisation is now helping us to understand how a population may divide into two species or speciate," explains John.

"Using amplified fragment length polymorphism (AFLP) - really a mutationfinding technique - we identified fragments of DNA that were varying between two forms in such a way to suggest that selection was going on.

"The next step was to take the genome of the snails and clone it into bacterial artificial chromosomes. You end up with tens of thousands of bacterial clones each with a small portion of snail DNA, with skill - and some luck - you have the entire genome across all the clones. We are now at the stage of linking genomic variation with likely differences between 'fitness' of different shell forms - for example one going for maximising reproductive output, one maximising ability to cling on to the shore.

"In the last year or so the group - which includes collaborators in Sheffield - has been using a new way of getting at DNA and it's been very successful. We think we are seeing several genes now which may be involved with the differences in shell form which are of such significance in resisting predators, for example.

"Why is this important? Well, it's apparent that some species may be good speciators, and others perhaps less so. We're losing biodiversity at a rapid rate so it's vital that we find out more about the process of speciation and the characteristics of good speciators. This knowledge may have a profound effect on how we approach conservation issues in the future.

"My research has everything a biologist could love: fieldwork, variations you can see, rigorous lab techniques and challenging analytical techniques. I still find it tremendously exciting."

Ilkely duo shed new light on Darwin
Charles Darwin's nine-week stay in the Yorkshire spa town of Ilkley is the common thread that has brought together two distinct but complementary strands of research to produce a book that sheds important new light on his life and health. Darwin in Ilkley covers the period just prior to, during and after the publication of On the Origin of Species by Means of Natural Selection in November 1859, when Darwin visited Ilkley to undergo hydropathic or 'water cure' therapy for a mystery illness.

The book is the result of collaboration between Emeritus Professor of Gastrointestinal Pathology Mike Dixon and Greg Radick, Senior Lecturer in History and Philosophy of Science. Each academic examined a specific area of Darwin's life when writing the book - Mike investigated Darwin's health and the treatments he underwent in Ilkley, whilst Greg examined the important correspondence that took place between Darwin and his scientific peers during the same period.

A keen local historian, Mike already had an in-depth knowledge of the treatments offered in Ilkley during the mid-19th century. "Ilkley was a small village when Darwin visited but it was famous for its water cure which is why he went there," explains Mike. "Darwin has often been portrayed as a hypochondriac but I think this is inaccurate; if he seems to be overly anxious about his health it was probably as a   result of the misery caused by persistent misdiagnosis and subsequent ill-advised remedies!"

Mike studied letters written by Darwin during the three months before, during and after his Ilkley stay and believes that some of the contents point to a diagnosis of lactose intolerance. "Like most correspondents of the day, Darwin frequently mentions his health in his letters," explains Mike. "By putting these regular 'bulletins' together and looking at them alongside what Darwin was doing at the time - whether  he was undergoing treatment, and thus on a restricted diet, or whether he was eating normally - we can monitor his symptoms and the possible causes.

"Darwin's wife Emma was a great believer in the health-giving properties of dairy products and it's known that Darwin had a sweet tooth. Eating this rich diet would certainly exacerbate symptoms of lactose intolerance and this is corroborated by the comments in his letters."

Mike isn't the first person to make this diagnosis, but he believes the subject has never been investigated as thoroughly. "Having looked at the evidence in the letters, Darwin's symptoms don't fit with other theories about his illness - which include a chronic disease acquired in South America, inner ear disturbances (Meniere's   disease), panic attacks with agoraphobia and many others. Although people may disagree with my conclusions, I think that using Darwin's letters to study the fluctuations in his health over a relatively short period has set a pattern that others will follow."

Greg's interest focuses on Darwin's intellectual activities in Ilkley, in particular the letters written to and received from his scientific peers. "His correspondence around this time is incredibly rich in its intensity and range as he seeks recruits for his theory, which he knows will be contentious," says Greg. "A complete collection of Darwin's Ilkley letters has been in print for some time but, because of their huge complexity, they don't invite a page by page reading, and historians haven't really dealt with letters from this period in such depth before."

Greg found the letters between Darwin and Charles Lyell - an eminent geologist who wrote one of the founding books of geological science, the Principles of Geology -   especially interesting. As a young man, Darwin had been profoundly influenced by Lyell and he was keen to get his opinion and approval of the theory he was about to make public in the Origin.

"Their correspondence during Darwin's stay in Ilkley is extremely hard-hitting and encompasses the most far-reaching implications of Darwin's theory, including what it means for a belief in the existence of a superintending God," continues Greg.

"Once I started to 'de-code' the letters, they became absolutely riveting and quite moving. You're listening in to a backstage conversation between two friends who are also, on the question of evolution, opponents.

"Our hope is that the book works on a local history level, and that it's also of interest to a much wider audience. Both the areas we've looked at are very important to Darwin scholars but, until now, his time in Ilkley hasn't been quite so thoroughly investigated. We'd like to think that our book makes a valuable contribution to understanding of Darwin's life."

Darwin in Ilkley is published by the History Press at £12.99 and is available to order.

Darwin Day
The University's Darwin Day proved a huge success, with a packed audience listening to key speakers, including the discoverer of DNA fingerprinting, Professor Sir Alec Jeffreys. Guests arriving for the lectures were treated to a display of three specially commissioned panels, representing the development of Darwin's theory: evolution, through observation, analysis and hypothesis. The panels were designed by Jennifer Jiyeon Han with the support of David Bromilow and Vanessa Walker (School of Design) in collaboration with Pamela Rabbitts (Leeds Institute of Molecular Medicine).