Obituary: Professor David Fulker

IN DAVID Fulker, the burgeoning field of behavioural genetics has lost one of its genuine stars.

Recently returning from a 13-year period in the United States, where he had been a Professor at the Institute for Behavioral Genetics and Department of Psychology at the University of Colorado, in 1996 he accepted a Chair in Statistical Genetics in the new Centre for Social, Genetic and Developmental Psychiatric Research at the Institute of Psychiatry in Camberwell, south London. Eventual understanding of the nature of human nature, in both its normal type, called "wild type" by geneticists, and psychiatrically impaired manifestations, requires the combinations of disciplines and approaches found in the new centre.

It usually comes as a surprise to learn that the term "genetics" was the idea of W. Bateson FRS in Britain in 1905, and the critical distinction between "genotype" (unseen, inferred) and "phenotype" (outwardly observable character), as well as the word "gene" for the elements inferred by Mendel in 1865, was only made in 1909 by W. Johannsen.

The speciality of behavioural genetics is the uneasy heir of the overly exuberant efforts of Sir Francis Galton (1822-1911) to answer the basic questions about the relative importance of nature versus nurture in their influence upon human behaviours; Galton was a cousin and contemporary of Charles Darwin.

It can now be firmly concluded from empirical data from the similarities and differences in behavioural traits and disorders gathered on twins, families, and adoptees (contrasting their biological with their adoptive relatives) that genetic factors, so far unspecified, account for some 50 per cent of the differences observed within our species as a whole. This conclusion was greatly bolstered by the fitting of complex mathematical models devised and adapted by David Fulker to the observed data that permitted a partitioning of the differences into genetic ones, environmental ones shared within a family, and environmental ones unique to members of a family.

Fulker, by virtue of some 200 published articles, chapters, and books - empirical as well as theoretical - on behavioural, statistical (quantitative) and molecular genetics, was recognised as an international treasure- resource. He received the coveted Theodosius Dobzhansky Award for Lifetime Contributions to Behavioral Genetics in 1995 and was the Executive Editor of the journal Behavior Genetics from 1985 until his death.

Fulker showed with carefully designed studies (of animals from mice to ourselves) that a major reason for such traits as anxiety, depression, reading disability, alcohol and drug abuse, intellectual abilities, and some varieties of sexual orientation being "familial" (running in families in complex ways) was importantly genetical, but also influenced to an extent by environments/experiences not shared by other members of their families. He had just initiated a study in the UK of 25,000 siblings to help identify the potential genes involved in differences in the expression of anxiety and depression.

He embodied in his thinking ideas that stemmed directly from K. Mather via J.L. Jinks and P.L. Broadhurst, from his days in the Sixties at Birmingham University, where he earned a masters degree in applied genetics and a PhD in psychology. To that he added the newest advances in the search for "quantitative trait loci" (QTLs), sub-regions of whole genes that can be detected, as both an innovator (with such American colleagues as J. DeFries, L. Cardon and S. Cherny) and an original contributor with high-visibility papers on reading dyslexia and sexual identification.

Shortly after his degree at Birmingham he produced a paper that is a classic in the field (with Jinks in 1970) in one of the most prestigious journals in psychology, the Psychological Bulletin, a prescient article that guaranteed the relevance of biometrical genetics and of animal genetics to the study of human behaviour. Fulker had used a sweeping set of animals (fruit flies, rats and mice) and strategies (diallel crosses, twins, adoptees and families) in attaining his goals. He did not shy away from controversial issues, an attitude perhaps learnt from his longtime colleague H.J. Eysenck; Fulker's review in 1975 of L. Kamin's book that disparaged the behavioural genetics research on IQ being a case in point.

Fulker's matter-of-fact and down-to-earth style, never raising his voice to make a point, hid a passionate concern for truth and justice.

David William Fulker, behavioural geneticist: born London 8 March 1937; Senior Lecturer in Psychology and Director of Animal Laboratories, Institute of Psychiatry 1975-85, Professor of Statistical Genetics 1996-98; Professor, University of Colorado 1985-96; married 1981 Angela Elliott (one daughter, one stepdaughter); died Boulder, Colorado 9 July 1998.