by Professor John Parker
One of the people who realised that Charles Darwin’s theory of evolution required a firmer base in heredity was Cambridge zoologist William Bateson (1861-1926) (right). Bateson began thinking about heredity along the lines laid down by Darwin’s cousin, Francis Galton, based on measurements of parents and their offspring. He soon realised that the way to proceed was to look at distinct differences in characters, not continuous ones like heights and weights, just as Gregor Mendel had already done in his 1865 paper. Mendel was an Austrian scientist and Augustinian monk who had demonstrated that heredity was determined by hard unyielding particles, later called genes, as opposed to Henslow, and his pupil, Darwin’s belief that heredity was soft and malleable, influenced by the environment. The scientific community, however, did not know about Mendel’s work at this time. As a consequence of this misunderstanding, for evolution by natural selection to proceed, Darwin had to propose that the changes in nature generating variation had to occur many times and in a particular direction. Darwin had to invent an imaginary system of particles, called ‘pangenes’, to account for this.
Bateson published a 600-page book in 1894, entitled ‘Materials for the Study of Variation treated with especial regard to Discontinuity in the Origin of Species‘, which he describes as ‘a contribution to the study of the problem of species’. It concerns animal variation, but Bateson began experimental work with plants and animals. He used land in the eastern, then undeveloped, part of the Botanic Garden.
In 1897, Bateson was awarded a grant from the Evolution Committee of the Royal Society and rented an allotment within the Garden of three eighths of an acre adjacent to the experimental area. Bateson experimented with butterflies and collaborated with the superb botanist Miss Edith Saunders, of Newnham College, in the study of plants. Soon they built up and cultivated an impressive list of plant species under investigation, and introduced poultry to the Botanic Garden a couple of years later.
In 1902, Bateson and Saunders reported their findings to the Royal Society. They had carried out genetic studies on: hairiness in red and white campions (Silene), yellow and black fruit colours in deadly nightshade (Atropa belladonna), stem colour and fruit types in thorn apple (Datura), and hairiness, flower colour and seed colour in stocks (Matthiola). In all cases, they confirmed that heredity conformed to a Mendelian pattern. Their poultry crosses demonstrated, for the first time, that Mendel’s results with peas also applied to animals.
Bateson and Saunders were joined in their research by others now famous in the history of genetics including R. C. Punnett now remembered for the ‘Punnett Square’ for working out expectations from Mendelian crosses. Crossing experiments became so extensive that a greenhouse was needed to carry them out. They obtained this through the Curator of the Garden, Richard Irwin Lynch (1879 – 1919), a development approved by the Botanic Garden Syndicate.
William Bateson credits Newnham graduate and biochemist, Muriel Wheldale, for the sweet pea (Lathyrus odoratus) illustrations in his publication, Mendel’s Principles of Heredity, in 1909.
Richard Irwin Lynch himself was drawn into this new science based on hybridisation, which was given the name ‘Genetics’ by Bateson in 1906 at the third International Conference of Genetics, organised by the Royal Horticultural Society. At that meeting there were many contributions from the Botanic Garden. Lynch presented an exhibit and gave a paper on natural hybrids while Edith Saunders exhibited species used in their genetic experiments and gave an authoritative paper on “Complications in the heredity of stocks (Matthiola)”. One of the major contributions to genetics came from studies on sweet peas (Lathyrus odoratus). Bateson and Punnett found that, remarkably, crossing a white- by a white-flowered plant gave a full-coloured offspring. They concluded that two independent genes controlled flower colour, so separating the analysis of genes from the characters they determined.
Many Cambridge people contributed to the Conference, as well as friends of Bateson’s. One of these was Charles Chamberlain Hurst, a gentleman with an estate in Leicestershire. His extraordinary contribution concerned the genetics of tomato and Antirrhinum colours, comb type in fowls, orchid hybrids, and the coat colours of rabbits. His connection with the Botanic Garden came later when he spent the last 25 years of his life here working out the origin of the garden roses. During these studies he made many hybrids named some for the Garden, for example, Rosa x cantabrigiensis, Rosa ‘Cantab’ and Rosa x coryana (for Reginald Cory, who left a major legacy to the Botanic Garden upon his death in 1934).
Bateson began his studies of genetics in the Botanic Garden before Mendel’s paper was re-discovered. As soon as it was, he became the great apostle of Mendel in the English-speaking world. Bateson’s great contributions to science were made in these early days at Cambridge, and are celebrated today in the plantings of the Genetics Garden here. His research centred on experimental breeding with Saunders and Punnett, and his ground-breaking work led to the foundation of genetics as a recognised biological discipline world-wide.
This article first appeared in the Friends Newsletter in 2009, as part of the celebration of the 800th anniversary of the University and the bicentenary of the birth of Charles Darwin.