It is with sadness that I learned today of the death on 25th December 2014 of Dr Mary Lyon FRS. I had only recently written about her, as someone who had been a source of inspiration to me during my early career:
“I joined the Genetics section of the MRC Radiobiology Unit, Harwell in 1976 and worked there until I left to start nurse training in 1985. Unusually for the time, the Head of section was a diminutive female scientist, Dr Mary Lyon. Gentle and quietly spoken, she nonetheless led a world class research laboratory of distinguished scientists, with vision and determination. As a new postgraduate researcher, I was completely in awe of her and she instilled in me the importance of attention to detail and the scientific approach.
Mary had a formidable intellect and the various awards and prizes she gained over her career were testimony to this, perhaps most notably the internationally prestigious Wolf Prize in Medicine, in 1997. As a Fellow of the Royal Society, she received a Royal Medal in 1984. She put forward the hypothesis of X-inactivation, proposing random inactivation of one of the two X chromosomes in the cells of female mammals during early embryogenesis. Representing an outstanding contribution to human medical genetics as well as mammalian genetics more widely, this mechanism is sometimes referred to as lyonisation, in recognition of her. It led to great advances in understanding of X-linked inherited diseases such as haemophilia – and explained how we get tortoiseshell cats! Mary also made a major contribution to understanding environmental mutagenesis and I had the privilege of conducting some research with her on an aspect of this. Mary Lyon was, and remains, an inspiration to women in science.”