Genetic Notes: Embarrassment of the neo-Darwinists

FIFTY YEARS before Charles Darwin's seminal Origin of Species the French biologist Jean Baptiste de Lamarck published his view on how animals evolved. A core idea, uniformly accepted by his peers, was that organisms adapting to a changing environment altered their bodily and behavioural characteristics and passed these acquired characteristics to their progeny. This is Lamarckian inheritance and is probably one of the most emotive issues in contemporary science (apart from the metaphysical issue of whether an all- powerful "God" exists).

Historical ironies abound. Both Charles Darwin and his grandfather Erasmus accepted Lamarckian modes of inheritance. The notion is overt in all of Charles Darwin's evolutionary analyses. Thus in 1868 he published his theory "Pangenesis" to explain the origin of genetic variations in nature because his evolution theory assumed the pre-existence of such genetic variation in populations of plants and animals, which are then subjected to natural selection to sort out the parents for the next generation - a process for which the philosopher Herbert Spencer coined the term "survival of the fittest". Therefore Darwin considered that, during a somatic, or bodily, change necessary for a particular adaptation, the body cells of the excited target organ would emit genetic material or "gemmules" (also termed "pangenes") which were considered to be minute representations of each normal or altered bodily component. These were discharged from the active organ into the bloodstream, thus allowing them to enter the germ cells (eggs and sperm) and be genetically transmitted to the next generation.

Darwin's late-19th-century and 20th-century followers, the neo-Darwinists, have been embarrassed by his genetic speculations and have, where possible, expunged them from the scientific record. Lamarck's contribution to modern genetics has been demonised; many interesting acquired inheritance phenomena have been suppressed.

It began in earnest in 1885 when August Weismann erected his now famous conceptual barrier protecting germ cells from any genetic changes within the soma or body of the organism and thus forbidding any form of acquired inheritance. Despite the intellectual efforts of heavyweight critics such as Arthur Koestler and Sir Fred Hoyle, neo-Darwinism sustained by Weismann's genetic chastity belt has reigned supreme throughout the 20th century, a development which would have mystified if not horrified Darwin.

We have all been witnesses therefore to the triumph of the "Darwinian dogma", that evolution proceeds only by the natural selection of chance events. In this century we have the tragic story of the Austrian biologist Paul Kammerer wonderfully told by Arthur Koestler in his 1971 book The Case of the Mid-Wife Toad and then the bizarre aberration of the so-called Lamarckian theory promulgated by Joseph Stalin's head of Soviet agriculture T.D. Lysenko (who, in the course of a ruinous 30- year career destroyed Soviet agriculture, biology and genetics).

So at the end of a turbulent and violent century neo- Darwinism apparently remains impregnable - much like Communism just before its dramatic implosion. Are neo-Darwinism and Weismannism, which reached their zenith during the Cold War, on the verge of a similar collapse?

We have marshalled and analysed the available molecular evidence on the functioning and evolution of the antibody genes of the immune system in a new book. Without a Lamarckian soma-to-germline gene feedback process it is difficult, if not impossible, to explain a large number of striking features of the DNA sequence structure of these genes. The challenge is for those other scientists, who really understand these data, viz. molecular immunologists, to come up with a better scientific explanation. We don't think there is one - outside of course those non-scientific propositions evoking an "intelligent gene manipulator" or, if you will, a "divine intervener".

Edward J. Steele, Robyn A. Lindley and Robert V. Blanden are the authors of `Lamarck's Signature: how retrogenes are changing Darwin's natural selection paradigm' (Allen & Unwin, pounds 8.99)