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Page 1: Many shades of green

Greg Clarke, the agency’sdirector of promotion andinternational initiatives, said therewere six large-scale collaborativeprojects with aims such asmaking the best use of thecapital’s science base.

London also has a world-classcollection of material forbiomedical scientists andhistorians. Apart from theinternationally renowned NaturalHistory Museum, the WellcomeCollection and Kew Gardens,many smaller bodies hold richhistorical material. The RoyalVeterinary College, the first of itskind in the world, holdsthousands of artefacts and booksdating back to its inception in1791. St Bartholomew’s Hospital,one of the world’s oldesthospitals, founded in 1123, holdsa substantial store of mediaevalartefacts and medicalinstruments, and many othersmaller collections also exist,providing a valuable resource.

The concentration of publicresources in London’s highereducation institutions means thatuniversities and colleges areunder constant pressure todemonstrate that the investmentsare justified.

Michael Driscoll, vicechancellor of MiddlesexUniversity, said it was easy toquestion the need for more than40 higher education institutes inone city. But he believed that thecombination of large and small,specialist and generalinstitutions, served its purposewell.

“London benefits from havingthe most diverse and rich highereducation sector of any city in theworld — not even New York orTokyo compares. It is an asset toBritain, not just London,” he said.

Collaboration is also to be‘steadily enhanced’ at theUniversity of London, thefederation of 19 colleges in thecapital, according to its vicechancellor, Sir Graeme Davies.

But cash remains a problem.The best UK universities trail wellbehind the best in the US in termsof endowed funds and incomeand this will be a key issue inbolstering the city’s case toachieve global status.

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The origin of species, despitethe title of Darwin’s key book,has remained an intriguingquestion for biologists. Withgrowing concern aboutbiodiversity and man’sincreasing threat to it, issues ofspecies richness are of growinginterest and urgency. A newstudy has looked at thedistribution of green lizards ofthe Anolis genus in Cuba.Although Cuba is largecompared with many otherislands in the Caribbean, it hasan extraordinary range of greenlizards — more than 60 speciesin total.

A new study reported in theProceedings of the RoyalSociety series B (publishedonline) has investigated theorigin of this Cuban diversity. Ateam led by Richard Glor atWashington University, St Louis,describes work on the Cubananole lizards.

Researchers have describedtwo main mechanisms forspeciation. Sympatricspeciation is often consideredas the main mechanism in

species-rich isolatedecosystems such as lakes orislands. It is thought thatpopulations may have adaptedto different features of thehabitat or that sexual selectionhas fragmented populations intodifferent species. Alternatively,allopatric speciation is thoughtto result from the physicalseparation of populations whichthen evolve along divergingroutes.

West Indian anoles representa classic example of a species-rich adaptive radiation withinseveral relatively small,geographically isolated areas.On Cuba, where anole diversityis highest, more than 60 speciesoccur over an area of only110,000 square kilometres. Mostanole species on Cuba andother Greater Antillean islandsresult from within-islandprocesses leading someresearchers to believe thatsympatric speciation has playeda role in anole diversification.However, the authors claim,several lines of evidencesuggest that geographical

Many shades of green

Distanced: The great variety of Anolis lizards in Cuba may result from previousinundation fragmenting the island. (Picture: Photolibrary.com)

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Q & A

Chris SomervilleChris Somerville is Director of theCarnegie Institution Departmentof Plant Biology and a professorof Biological Sciences atStanford University. He grew upin the Canadian north and waseducated at the University ofAlberta. He was one of the earlyArabidopsis enthusiasts and hasused the plant to study a varietyof topics in cell and molecularbiology. He is currently exploringthe complexities of plant cell wallbiogenesis.

How did you get into biology? Idid my first degree inmathematics because I had thefalse impression thatunderstanding the structure ofmathematics was equivalent tounderstanding the designprinciples of the universe. When Irealized that this was not correct,I lost interest in mathematics andbecame interested inunderstanding what life was andhow it could create mathematics.I became attracted by theelegance and rigor of lambdagenetics and did a Ph.D. on generegulation in Escherichia coli.

Was anyone a key influence?The person who brought me intoscience as a profession was KenMorgan, a human populationgeneticist who is now at McGillUniversity. Because I knewseveral computer languages, Kenhired me after my first degree asa research assistant to help witha problematic computersimulation of a humanpopulation. We used to work lateinto the evening and ended thedays talking about what wasscientifically interesting and alsoabout how the academic worldfunctions. He encouraged me tolearn biology and provided a lotof good advice about what wasimportant in life. I still find myselfpassing on aspects of hiswisdom to my colleagues,postdocs and students.

My partner and colleagueShauna Somerville has also had a

profound effect on my scientificlife. We jointly envisioned whatmight be possible withArabidopsis when we were livingin Paris on a kind of extendedvacation following my Ph.D. andwe have had adjoining labs forthe past twenty-five years. Wediscuss our work every day andshe has contributed countlessinsights and ideas. We haveacquired complementaryknowledge but I cannot separatemy ideas from hers.

Why do you work on plants?When we were young, Shaunaand I set out to try and dosomething to address the effectsof adding 80 million people a yearto the world population. We were,and are, concerned about theeffects of population growth onthe environment and quality of lifefor hundreds of millions of people.Part of the solution is to increaseplant productivity so that morefood and fibre can be producedwith the available land and waterresources. Our idea was thatdeveloping an effective modelplant would be the most effectiveway to make advances in plantproductivity. This idea led us toArabidopsis. We knew at the timethat it had a very small amount ofDNA and considered that anadvantage because we were stillstruggling with basic cloning andsequencing. That feature turnedout to be a greater than expectedblessing because it ultimatelyenabled the development of thevery powerful genometechnologies that we haveavailable today.

Our experience of the pasttwenty-five years has reinforcedthe original vision and we arenow beginning to see theknowledge obtained from basicresearch on the models appliedto food production. That successhas kept us in the field in spite ofthe limited funding and thewidespread lack of interest inplants among biologists.

Was there a single influentialpaper? The paper that really setthe course of my research was a1977 article by Mary Dell Chilton,Gene Nester and colleaguesshowing that Agrobacterium

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processes have played adominant role in intra-islandanole speciation.

On Cuba, the authorsbelieve one overlookedmechanism of speciation mayhave been the geographicalseparation of regions of theisland during historicallyhigher sea levels.Reconstructions suggest thatthis island consisted of threedistinct archipelagosseparated by deep waterchannels throughout much ofthe Cenozoic era before beingpermanently reunited in thePliocene. Evidence forfragmentation of Cuba duringthe Miocene is compelling,the authors believe.

The researchers thereforecarried out sequenceanalyses of mitochondrial andnuclear DNA from samplestaken from more than 300individuals of two species at54 locations throughout Cuba.

Their results support thehypothesis that partialsubmersion of Cuba duringthe Miocene initiatedspeciation among populationsof green anoles. Despite theirlimited geographical range,historical barriers to geneexchange separated lineagesthat have maintained theirevolutionary distinctnessthrough long periods ofevolutionary time.

If this pattern is general,accumulation of allopatricspeciation over many millionsof years of evolutionaryhistory has probably beenimportant for Anolis speciesdiversification and sympatricspeciation processes are notrequired to explain thegroup’s high speciesrichness.

The generality of theseconclusions should be testedusing other taxa from Cuba,the authors believe. Thelesson appears to be that inthe face of any case ofspecies diversity, a deepstudy of geographical historymay help throw light on thepresent situation.


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