Handedness frequency over more than ten thousand years

Although there are quite important geographical variations in the frequency of left-handers around the world, nothing is known about its temporal evolution. During the upper Palaeolithic (ca. 35,000-10,000 YBP), humans painted 'negative hands' by blowing pigments with a tube onto one hand applied on the rock in caves in Western Europe, by blowing pigments on their own hand through a tube held in the other hand. The frequency of left-handers prevailing during this period could thus be assessed. For comparison, the handedness of French university students has been observed for the same task. No difference was detected between the two proportions of left-handers, separated by more than 10,000 years. Implications for the evolution of the polymorphism of handedness are discussed.     

Widespread conservation of genetic redundancy during a billion years of eukaryotic evolution

Genetic redundancy means that two genes can perform the same function. Using a comprehensive phylogenetic analysis, we show here in both Saccharomyces cerevisiae and Caenorhabditis elegans that genetic redundancy is not just a transient consequence of gene duplication, but is often an evolutionary stable state. In multiple examples, genes have retained redundant functions since the divergence of the animal, plant and fungi kingdoms over a billion years ago. The stable conservation of genetic redundancy contrasts with the more rapid evolution of genetic interactions between unrelated genes and can be explained by theoretical models including a 'piggyback' mechanism in which overlapping redundant functions are co-selected with nonredundant ones.     

从事药理学研究四十余年的回顾

张均田教授是我国著名的药理学家、中国药理学会理事长。他毕生致力于神经药理学研究 ,特别是在新药研制和药理实验方法学的创立上都做出了重要贡献。他对促进人才培养方面的精辟见解 ,及其对人生的乐观态度 ,使人深受启发。     

Metazoan evolution: some animals are more equal than others

Comparison of newly available sequence data facilitates reconstruction of the gene inventory of the Urbilateria, the last common ancestor of flies, nematodes and humans. The most surprising outcome is that human genes seem to be closer to the bilaterian roots than previously assumed.