was best known for her
pioneering research in understanding the genetics of mating in basidiomycete fungi.
Lorna Casselton (née Smith) was born on the 18th July 1938, and was the daughter of William Charles Henry Smith and Cecile Smith (née Bowman).
William Smith was a keen amateur naturalist and encouraged his daughters Lorna and Pamela to become biologists.
From an early age Lorna
became very interested in planting and propagating crops and developed a passion for biology and genetics in particular, which would last for her
Lorna first attended Southend High School for Girls and then attended University College London where she gained a BSc in Botany and a PhD in 1964.
sister were the first generation of their family to attend University.
In Dan Lewis's laboratory, Lorna
started working on the basidiomycete fungus Coprinopsis cinerea (then known as Coprinus lagopus and subsequently C. cinerea).
In Dan Lewis' laboratory, Lorna
developed a successful technique for generating diploids of Coprinopsis, which greatly facilitated genetic analysis and therefore provided a deeper insight into the genetics of mating.
years at UCL
as a PhD student indeed led to many of the techniques that were subsequently utilised by Lorna
independent scientific career and she
was both a quick learner and a determined student with ambitions to lead her
own research group.
Lorna first moved to a position as Assistant Lecturer in Royal Holloway College London, before becoming a lecturer and subsequently, Professor of Genetics at Queen Mary College, University of London in 1989.
was later awarded an AFRC/BBSRC Postdoctoral Fellowship, which was followed by BBSRC Senior Research Fellowship in 1995.
It was during this period that Lorna
moved to the Department of Plant Sciences at the University of Oxford
remained for the rest of her
She was appointed Professor of Fungal Genetics in 1997 and a fellow of St Cross College, Oxford between 1993 and 2003, and was an Honorary Fellow of St Hilda's College, Oxford from 2000.
pioneering contributions were to work out the genetic basis of mating in Coprinopsis, as she
had set out to do upon graduating from the Lewis laboratory at UCL
Lorna set about identifying the genes involved in sex determination and through painstaking genetic analysis and molecular biology over more than two decades, she
was able to identify the genes that specify each sex and then show how their products interact with each other to allow recognition between different sexes to occur and for mating to proceed.
students identified the genes residing at the A and B mating type loci, which are unlinked chromosomal loci, each containing multiple genes.
Critically, in a series of seminal research papers Lorna
colleagues, most notably Ursula Kües, showed that the A loci contain two genes that encode homeodomain proteins which form heterodimers which are necessary for successful mating and which transcriptionally regulate sexual reproduction and the onset of meiosis.
was also able to determine how different mating type proteins interact with one another to form heterodimers and in this way to show how compatible mating couples could have sex successfully.
also showed how the B locus contains multiple genes that are involved in pheromone production and a single gene that encodes a cognate pheromone receptor, a Gprotein-coupled receptor.
Therefore in order to mate successfully Coprinopsis has to have different alleles at both A and B loci, which are necessary for the correct pheromone-receptor combination to effect formation of a dikaryon and for an appropriate heterodimeric transcription factor to be produced to regulate sexual reproduction and meiosis.
It was for these key discoveries into the operation of tetrapolar mating systems in fungi that Professor Casselton was elected a Fellow of the Royal Society in 1999.
She was also honoured by the British Mycological Society, who made her an Honorary Member in 2002, and by Societies of Mycology and Fungal Genetics from across the globe.
Lorna was a tenacious and skillful scientist, who pursued a problem of enormous technical difficulty and genetic complexity.
The fact that she
overcame these challenges was a testament to her
strength of character and her
ability to motivate those around her
was relentlessly enthusiastic about her
science, which influenced many other fungal geneticists (including myself), and she
also had very exacting standards.
Lorna was a formidable critic of sloppy thinking and poorly designed experiments and did not suffer fools gladly.
unremitting commitment to scientific excellence was the principal reason she
was so successful in studying such a difficult research question.
also trained some highly successful scientists, including the late Norman Todd (her first PhD student), and leading fungal biologists Ursula Kües and Meritxell Riquelme.
was also, however, fantastic company with a very keen sense of humour- indeed she
had a sparkling wit.
The fact that Lorna
worked on the most intimate details of the 'private lives' of fungi was certainly not lost on her
could add the appropriate level of innuendo into her
presentations to keep the audience fully engaged.
At the Asilomar Fungal Genetics Conferences, of which she
was a regular attendee and Plenary Speaker, she
was once given the honour of delivering an after dinner speech in which regaled the audience with tales of her
life in science and also read us a love poem between two Coprinopsis individual meeting for the first time.
Lorna was an incredibly influence on many of the leading fungal biologists working today across the world and was arguably the most important and prominent fungal biologist of the UK in the last 30 years.
Following her election to the Royal Society in 1999, Lorna served on their governing Council from 2002-2003 and in 2006 she was elected Vice-President and Foreign Secretary of the Royal Society.
As Foreign Secretary, Lorna travelled very widely, visiting 27 different countries during her three and a half years in office.
She was an immensely popular and active Foreign Secretary of the Royal Society, a fantastic ambassador for Fungal Biology and Biology more widely, as well as a strong proponent of the importance of women in science and a recognized leader in her field.
She became a Member of the Academia Europaea in 2008 and was awarded an Honorary Doctorate of Science of University College London in September 2010.
She was appointed Commander of the Order of the British Empire (CBE) in the 2012 Birthday Honours for services to fungal genetics and international science.
was very happily married to William Tollett, a pilot, with whom she
shared a passion for flying and adventure.
is sadly missed by all who knew her
and who respected her
approach to science, her
great skill and tenacity, her
commitment to excellence and her
sheer force of energy.