Francis Crick underneath hearth from an embryologist

This letter appeared in Nature in 1970:

Diffusion in Embryogenesis

SIR,—As an embryologist who began work in the course of the heyday of “fields” and “gradients”, I suppose I must be grateful to Dr Francis Crick for permitting me a nostalgic look again at these long-discredited ideas which he has now resurrected—or ought to I say, canonized—with the double halo of his personal popularity and a few elegant arithmetic (Nature, 225, 420; 1970). There’s, nevertheless, one level that he seems to miss: the intense rarity with which sheer diffusion processes happen in dwelling programs. Twenty years in the past my better-informed colleagues instructed me about energetic transport and permeases. Ever since then, if supplies have subtle out and in of my experimental embryos, I’ve regarded it as an indication that they’re dying or lifeless. A sheet of frozen-dried tissue, prolonged between supply and sink, may match Dr Crick’s formulae, but-alas-it wouldn’t differentiate!

Yours faithfully


The Medical Faculty, College of Bristol

Effectively, Francis Crick couldn’t fail to get that message. Depart it to the true embryologists is the bit between the traces. And certainly Elizabeth Marion Deuchar was an actual embryologist within the days earlier than embryology morphed into developmental biology. She was born on 13 February 1927 in Biggleswade, Bedfordshire. After graduating in zoology from Oxford in 1948 she moved to Edinburgh the place as a member of employees of the Agricultural Analysis Council (now BBSRC) on the Animal Breeding Analysis Organisation she labored with Conrad Hal Waddington FRS (1905-1975) for a PhD. From 1953 to 1966 she was Lecturer after which Reader in Embryology at College Faculty London. She then seems to have taken what turned out to be a really totally different path. She resigned with a view to attend theological school. Nevertheless, in 1968 she returned to embryology, within the Division of Anatomy at Bristol. She married in 1972 on the then late age of 45 and moved to the College of Exeter. Elizabeth Deuchar died of most cancers on 26 January 1979 close to Axminster in Devon, aged 52.

The query now could be: was she proper in difficult Crick? The reply should be no as a result of she appears to have confused motion of drugs throughout cell membranes, the place easy diffusion is certainly uncommon, with motion between cells within the extracellular house or, as proven later, from cell to cell via ‘hole’ junctions. The arguments of whether or not a easy diffusion gradient, to which cells reply relying on the focus of a signalling chemical to which they’re uncovered, is modified by, for instance, binding of the substance by cells, proceed.

Ruth Bellairs (1926-2021), her former colleague at College Faculty London, who wrote an obituary for the Journal of Embryology and Experimental Morphology thought extremely of her: 

Elizabeth Deuchar printed over 60 scientific papers and three books, however her affect on the topic went far past that. Other than the truth that she was an inspiring trainer to a number of generations of undergraduates and Ph.D. college students, she was a type of devoted scientists who quietly organise conferences and seminars, sit on committees and provides their time unselfishly to assist others. 

Extra lately, John Wallingford of the College of Texas at Austin, in his 2022 chapter on the historical past of Xenopus in analysis which he kindly despatched to me, mentioned the spat with Crick and reached the identical conclusion as I did. Nevertheless, he additionally consists of one other Deuchar gem:

When a developmental biologist says “in mammals” he most likely means “within the mouse”; by “in birds” he nearly actually means “within the chick”. When he generalizes extra broadly than this about mechanisms of differentiation in “all growing cells” there’s a hazard that he’s referring to work carried out completely on Xenopus. 

—Elizabeth Deuchar (1972) 


Elizabeth Marion Deuchar

Bellairs R. 1980. Dr Elizabeth Marion Deuchar (1927–1979). Journal of Embryology and Experimental Morphology. 57,1–2.

Deuchar EM. 1970. Diffusion in embryogenesis. Nature 225, 671. 10.1038/225671b0

Kuhn T, Landge AN, Mörsdorf D, Coßmann J, Gerstenecker J, Čapek D, Müller P, Gebhardt JCM. 2022. Single-molecule monitoring of Nodal and Lefty in reside zebrafish embryos helps hindered diffusion mannequin. Nat Commun 13, 6101 doi 10.1038/s41467-022-33704-z

Wallingford JB. 2022. A fast historical past of Xenopus. “The common-or-garden batrachian”. In, Xenopus. From Primary Biology to Illness Fashions within the Genomic Period. edited by Abraham Fainsod and Sally A Moody. p1-12. Boca Baton, Florida and Abingdon, Oxford: CRC Press. doi: 10.1201/9781003050230-2 

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