Egalitarian motives in humans

Participants in laboratory games are often willing to alter others' incomes at a cost to themselves, and this behaviour has the effect of promoting cooperation. What motivates this action is unclear: punishment and reward aimed at promoting cooperation cannot be distinguished from attempts to produce equality. To understand costly taking and costly giving, we create an experimental game that isolates egalitarian motives. The results show that subjects reduce and augment others' incomes, at a personal cost, even when there is no cooperative behaviour to be reinforced. Furthermore, the size and frequency of income alterations are strongly influenced by inequality. Emotions towards top earners become increasingly negative as inequality increases, and those who express these emotions spend more to reduce above-average earners' incomes and to increase below-average earners' incomes. The results suggest that egalitarian motives affect income-altering behaviours, and may therefore be an important factor underlying the evolution of strong reciprocity and, hence, cooperation in humans.     

俄罗斯拟松材线虫的致病性

调查表明在俄罗斯目前尚未发现松材线虫的分布,但是有松材线虫的近缘种拟松材线虫的分布。在温室中利用从俄罗斯远东地区天然病死树上分离到拟松材线虫BmRFE,其分离物的接种实验表明,BmRFE分离物可使5年生Pinus koraiensis和Larix olgensis全部死亡,而70 %的P.sylvestris和P.densiflora可存活下来。室外试验的结果表明,用3种拟松材线虫分离物接种黑松,1 a之后只有BmRFE接种的2年生黑松中的线虫存活下来。在第2次试验的南方利用B.mucronatus(BmKOMY)和法国拟松材线虫分离物(BmFr),及两者杂交种分离物接种4年生P.sylvestris,结果表明接种后1 a几乎所有分离物均存活下来了,但是只有接种BmFr的松树表现出病害症状。病状的严重程度与拟松材线虫携带的致病细菌的毒性有关。毒性生测证明拟松材线虫BmRFE分离物携带了致病性最强的细菌。     

Accurate whole-genome sequencing and haplotyping from 10 to 20 human cells

Recent advances in whole-genome sequencing have brought the vision of personal genomics and genomic medicine closer to reality. However, current methods lack clinical accuracy and the ability to describe the context (haplotypes) in which genome variants co-occur in a cost-effective manner. Here we describe a low-cost DNA sequencing and haplotyping process, long fragment read (LFR) technology, which is similar to sequencing long single DNA molecules without cloning or separation of metaphase chromosomes. In this study, ten LFR libraries were made using only ～100?picograms of human DNA per sample. Up to 97% of the heterozygous single nucleotide variants were assembled into long haplotype contigs. Removal of false positive single nucleotide variants not phased by multiple LFR haplotypes resulted in a final genome error rate of 1 in 10?megabases. Cost-effective and accurate genome sequencing and haplotyping from 10-20 human cells, as demonstrated here, will enable comprehensive genetic studies and diverse clinical applications.     

Animal behaviour: continuous activity in cetaceans after birth

All mammals previously studied take maximal rest or sleep after birth, with the amount gradually decreasing as they grow to adulthood, and adult fruitflies and rats die if they are forcibly deprived of sleep. It has therefore been assumed that sleep is necessary for development and serves a vital function in adults. But we show here that, unlike terrestrial mammals, killer-whale and bottlenose-dolphin neonates and their mothers show little or no typical sleep behaviour for the first postpartum month, avoiding obstacles and remaining mobile for 24 hours a day. We find that neonates and their mothers gradually increase the amount of time they spend resting to normal adult levels over a period of several months, but never exceed these levels. Our findings indicate either that sleep behaviour may not have the developmental and life-sustaining functions attributed to it, or that alternative mechanisms may have evolved in cetaceans.