Plant culture: thirteen seasonal pieces. January--bark,the skin of a tree

To a remarkable extent current science, and the attitudes ofcurrent scientists, correspond to an idea conceived by FrancisBacon 400 years ago. Bacon dreamed of using science to subjugatenature for mankind. This is illustrated here by a science-eye'sview of bark, a feature of plants particularly apparent in January.But much of the beauty and value of plants is missed by Baconiananalysis. The touching story of Daphne's metamorphosis intoa laurel, her skin becoming bark, shows one such dimension,highlighted in the sculpture by Bernini.     

Linkage disequilibrium: what history has to tell us

Linkage disequilibrium has become important in the context of gene mapping. We argue that to understand the pattern of association between alleles at different loci, and of DNA sequence polymorphism in general, it is useful first to consider the underlying genealogy of the chromosomes. The stochastic process known as the coalescent is a convenient way to model such genealogies, and in this paper we set out the theory behind the coalescent and its implications for understanding linkage disequilibrium.     

Plant tissue culture. Biotechnology. Milestones

Summary The progress in the development of the technologies of plant tissue and cell culture over the past four decades has been remarkable. This article covers my personal reflections on the various topics and is based on my involvement in the field during that period. There are three fundamental technologies which constitute most of what is referred to as plant in vitro technologies or tissue culture. The origin and some of the key persons involved in the development of each of these procedures will be discussed. The technology that is most common is growing plant tissue on gel-solidified nutrient media. That technology is being used in the most vital procedures, namely the regeneration of plants from cultured cells. The culture of plant cells in liquid suspension was developed very shortly after that, and has become a very effective technology for plant regeneration by somatic embryogenesis. The method of meristem culture arose out of a need for developing plants that were virus-free. In many species the technique is now being used to produce virus-free crop plants. Another important technology is the culture of anthers and microspores for producing haploid and homozygous plants. Included with plant tissue culture is the development of the plant protoplast and cell fusion technologies for the production of new plant hybrids. The final aspect of the development concerns the integration of tissue culture with molecular genetics, which has developed into the rapidly expanding field of biotechnology.     

Plant tissue culture: A history

The author has lived in the plant tissue culture history since its beginning and had the opportunity to discuss with all the pioneers. Then in the present contribution he expresses personal memories, some of them being almost unknown. The tissue culture problem was suggested as soon as 1838 by Schleiden and Schwann's cell theory. The first experimental approach was vainly tried by Haberlandt in 1902. Following Carrel's success with animal cells, encouraging results were obtained on plants tissues by Gautheret in 1934 and the problem was definitely solved in 1939, independently by Gautheret, Nobécourt and White. The progress was slow because this new field interested only a few people. However in 1954 the principal chapters of this subject were already opened: Tissue culture, cell culture, improving of nutrients, especially of growth substances, expertness of organ formation and vegetative propagation, attempts to obtain secondary products and application to pathological problems. Later, in 1966 the androgenesis was initiated by Guha and Maheshwari, while Küster's pioneer work on protoplast fusion was exhumed and brought about innumerable investigations. Finally, for the past ten years plant tissue culture has truly exploded and now more than ten thousand people are engaged in this field: International Congress held in July 1982 at Lake Yamanaka, Japan is evidence for this effusive development.     

Meat made us moral: a hypothesis on the nature and evolution of moral judgment

In the first part of the article, an account of moral judgment in terms of emotional dispositions is given. This account provides an expressivist explanation of three important features of moral demands: inescapability, authority independence and meriting. In the second part of the article, some ideas initially put forward by Christopher Boehm are developed and modified in order to provide a hypothesis about the evolution of the ability to token moral judgments. This hypothesis makes evolutionary sense of inescapability, authority independence and meriting. It does so by referring to the selection pressures generated in the Late Pleistocene by large-game hunting. If the hypothesis is correct, we can say that, in a sense, meat made us moral.