Forgotten Prophet of Genetics
The Man Who Invented the Chromosome: A Life of Cyril
Darlington. Oren S. Harman. xii + 329 pp. Harvard University
Cyril Darlington was an impressive figure: Well over six feet tall
with a frame to match his height, handsome and debonair, a fresh
rose in his jacket lapel, Oxford's Sherardian Professor of Botany
looked the part. Although he was, in his day, one of the foremost
cytologists in the world, he was also an enthusiastic student of
history and a devoted gardener. He learned to garden as a child and
subsequently expressed this enthusiasm in the genetic garden he
created at the University of Oxford and in the historic Botanic
Garden there; he also planned two arboreta (both achieved). His
passion to account for history in genetic terms led him to write a
mammoth book, The Evolution of Man and Society (1969).
The son of a Lancashire schoolmaster, Darlington graduated from Wye
College with a London University degree and found unpaid work at the
John Innes Horticultural Institute, which was directed at that time
by William Bateson, an "apostle" of Mendelism. Sixteen
years later Darlington became director. By the time he left in 1953
(after 30 years) to assume the chair of botany at Oxford, he had
built for himself and the institute an international reputation.
Like Darwin, Darlington was systematic in preserving documents
pertaining to his life and work. His papers are a treasure trove for
the biographer. Oren Solomon Harman has made full use of them in
The Man Who Invented the Chromosome, supplementing them
with interviews of surviving colleagues. The book has four main
sections, devoted to Darlington's early career, his major creative
period in cytology at the John Innes Horticultural Institute, his
response to Marxism and to Lysenkoism (which in the 1930s resulted
in some Soviet geneticists being declared "enemies of the
people" and shot), and his public statements about his genetic
view of man and society.
Harman encompasses this agenda in an evenhanded manner, avoiding as
far as possible making personal judgments about his subject. This
cannot have been easy, because Darlington's strong hereditarian and
racist pronouncements, many of them laced with derision and
ridicule, invite challenge. But no matter how objectionable
Darlington's utterances on race, class, intelligence, culture and
history, Harman keeps his cool. Instead of fulminating, he lets his
sources mete out the judgments. At the end he muses on the story he
has told: "No one can remain indifferent" to it, he
opines, or to "the lessons it offers about the interplay of
ideas and the way we express and act on them." For Harman,
"the passionate expression and vigorous challenge of new ideas,
and their application to society, is where the future of mankind lies."
The title of the book signals the disputed status of the chromosome
in the 1920s and points toward the imaginative and creative
synthesis of the subject that Darlington achieved. By the time he
entered the field in 1923, a consensus had developed regarding how
chromosomes assemble at the onset of cell division and then split in
two, with each daughter chromosome traveling to opposite poles of
the cell. But the division process leading to the formation of the
sperm and egg was disputed territory. Here, like chromosomes
(paternal and maternal) associate in pairs. Do they associate
end-to-end or side-by-side? Using plants, Darlington established
that it is the latter. He went on to sort out the puzzling case of
the association of chromosomes in rings in the evening primrose, and
as a theorist he both clarified and unified chromosome behavior
across the board in his book Recent Advances in Cytology
(1932), a tour de force. But his method, although it drew
upon a wealth of data, was conjectural, involving a degree of
speculation that empirically inclined biologists were reluctant to accept.
Harman brings out clearly the central feature of Darlington's
conception of cytology: his view that the chromosome is a dynamic
unit—a vital part of "the genetic systems" that
organize and suppress to varying degrees the indeterminacy of
mutation and recombination. Control of cell division, control of the
degree of inbreeding or outbreeding, and control of sterility or
fertility are genetically based, he thought, and the genetics of
these systems is itself subject to selection, just as are the genes
that determine other traits. With such a view, Darlington could not
but deplore the naiveté of the population geneticists'
equations, which to all intents and purposes treat the gene as an
independent unit in heredity. Yet, like the population geneticists,
he wanted to approach the genetic system from an evolutionary point
of view. These ideas he first aired in a chapter of Recent
Advances in Cytology, but in 1939 he expanded on them in
The Evolution of Genetic Systems. Genetic systems, he
explained, "rest on a basis of chromosomes and are related to
one another by processes of natural selection." This
combination of "the material basis with the evolutionary
framework," he declared, "provides the only means of
making sense of biology as a whole."
The greatest strength of Harman's book lies in the exposition and
analysis he provides of Darlington's views on the evolution and
history of man and society. It is, of course, a starkly hereditarian
view, but Harman shows its organic relation with Darlington's
biological conception of genetic systems.
The fact that until now there has been no full-length biography of
Darlington underlines the extent to which he has been forgotten. The
molecular revolution left him behind, and the political climate
rendered his views on man and society increasingly unacceptable.
Harman's biography is therefore especially welcome. It is a valuable
source for the student of the biology of the first half of the 20th
century, and Harman's discussion of Darlington's genetic approach to
the historical and social realms is penetrating.
No biography of a cytologist is likely to make an easy read.
Cytogenetics is a very visual science. Those unfamiliar with its
jargon and visual content will need more assistance than Harman has
provided. Without helpful photographs of the stages in meiosis as
seen through the microscope, it is difficult for the uninitiated to
grasp why interpreting them proved so difficult. Also, Harman would
have been wise to focus more strictly on the relation between
Mendelian heredity and the chromosomes rather than including the
Mendelian-biometric debate and much else. That said, he has provided
a scholarly, powerful and at times devastating, but also subtle,
analysis of his subject.—Robert Olby, History and
Philosophy of Science, University of Pittsburgh
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