Tuesday, 9 December 2014

A classical geneticist

Mary Lyon, the geneticist, was born on 15 May 1925 and didn't graduate from Cambridge University in 1946 because the dons then considered women to be untermensch.  Nevertheless, she attended a requisite number of courses and took the degree examinations with the men and parlayed her unofficial paperwork into a PhD. Cambridge finally accorded equality in that they allowed women to graduate properly in 1948. Don't get the impression that there is no gender bias there (or indeed elsewhere) now or that the gate of promotion doesn't get straiter as academics climb the ladder. One recent Irish example. What I'm trying to say is that just to progress normally took gritted teeth, swallowed pride and a well developed sense of self.  If you needed assertiveness training as a woman in science in the 20th century you were really setting yourself to scale Mount Impossible.

Lyon started her PhD work with the legendary RA Fisher, one (with JBS Haldane and Sewell Wright) of the triumvirate of mid-20th century mathematically able scientists who put evolutionary genetics on a solid statistical and mathematical footing.  Fisher could be arbitrary and disagreeable and most of his proteges spread their wings rather quickly and flew elsewhere.  Lyon travelled North to work with CH "Canalisation" Waddington and Douglas Falconer (who wrote the text book) in Edinburgh. A few years later, the Edinburgh mouse geneticists moved South to Harwell near Oxford where all the radiation boffins were housed by the British government. More importantly there were facilities for housing the large numbers of lab mice that were required to do genetic research. Lyon discovered and characterised a number of novel mutants including years of work on the t-complex in the mouse Mus musculus.  It is called a complex because the 30Mbp region of mouse chromosome 17 comprehends a number of different genes. But for ordinary students like myself, who came long after, it was complex in a head-wrecking sort of way.  It was hard enough to follow the t-complex's violation of the laws of normal heredity when it was all worked out and could be carefully and s l o w l y explained. Only someone who was considerably smarter than me could have solved the several conundrums posed by the swamp of real data from numerous crosses so that they could be explained later.

I was writing a couple days ago about Dr. Lyon's eponym lyonisation and that's about all she's known for to the current generation of geneticists, which is a little ironic because her 1961 Nature paper describing the phenomenon of X-chromosome inactivation is a) really short and b) really short on original data and, if the truth of 20/20 hindsight be told, c) short on original ideas. She modestly tribbed one of the giants on whose shoulders she stood by calling the visible evidence of X-chromosome condensation "Barr" bodies. But Lyon put the whole hypothesis and its supporting evidence all down in such a coherent way that it made sense to everyone who read it. That's what it takes to shift the paradigm, that's what Crick and Watson did in their own data-short paper about the structure of DNA in 1953. It didn't make sense to Hans Gr√ľneberg FRS, an establishment mouse geneticist, who went out of his way to rubbish it. This curmudgeonly reaction seems, from a modern perspective, to have been driven by an unwillingness to be dragged into a new way of seeing by a much younger woman.

You can hear more from the horse's mouth in a respectful PLOS Genetics interview with Jane Gitschier.  The portrait at the top of the page is by Dr Lizzie Burns who is making a living with her art.  Having been trained as a molecular biologist (to PhD) she is now employed by the British Medical Research Council to show off the science which they fund and explain science to kids and Jo Public. Mary Lyon is still with us and continued working for years after her official retirement.  She was elected Fellow of the Royal Society in 1972 and has accumulated numerous other awards and prizes. Not particularly charismatic in a Hello magazine celeb sort of way, but solid, hard-working, dependable and insightful, Mary Lyon is a heroine of science. Bonnets off! 


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