My mother's gift--the link between honesty and hope

Doctors and other care providers often refuse to be direct and straightforward with patients needing end-of-life care because they do not want to take away hope. But the resiliency of hope is not linked with continuing life. Using introspection, a review of the literature, and a sampling of opinions gleaned from members and friends of the Midwest Bioethics Center, the author of this article concludes that all patients should be given full and forthright knowledge about the prognoses--not in spite of the patient's need for hope, but in hope's service.     

Reversing mother's curse revisited

Because of maternal mtDNA inheritance, mtDNA mutations detrimental only in males are not expected to be selected against, an effect termed the "mother's curse." However, if there is positive-assortative mating, equivalent to what was called "inbreeding" by Wade and Brandvain (2009), then selection can act to reduce the frequency of these male-specific detrimental mtDNA mutants. On the other hand, as shown here negative-assortative mating, or "outbreeding, " paradoxically can result in an increase in the frequency of male-specific detrimental mtDNA mutants. The implications of these findings are briefly discussed.     

The primary cilium: keeper of the key to cell division

Assembly of the nonmotile primary cilium of vertebrate cells requires one of the centrioles of the centrosome. A cluster of new studies, including one in this issue of Cell by Pugacheva et al. (2007), reveal that ciliary assembly proteins influence cell-cycle progression and that a centrosomal "mitotic kinase" promotes ciliary disassembly. The link between the cell cycle and the primary cilium may reflect a requirement for liberation of the ciliary centriole to allow the centrosome to form the mitotic spindle.     

Evolutionary ecology: wasp mother's little helpers

The medical application of antibiotics dramatically reduced human infant mortality in the previous century. A new study indicates that ground nesting wasps exploit Streptomyces strains that they rear in their antennae for the same purpose.     

Not my brother's keeper: A thought experiment for Hamilton's rule

The now popular ‘selfish gene’ view defines evolutionary fitness at the gene level - in terms of the number of gene copies residing in future generations (or propelled from previous generations). Yet, most current biology textbooks still apply the concept of fitness to the individual, where it is defined more traditionally as the number of descendants residing in future generations. The existing literature remains ambiguous regarding whether one of these concepts is more meaningful than the other, or whether they both represent legitimate, functional definitions of fitness. In support of the latter view, I present a composite perspective that recognizes the gene as evolutionarily ‘selfish’, but also the individual as a ‘selfish vehicle’ for resident genes. Hamilton's rule explains, based on genetic relatedness, why natural selection has favoured behaviours that compel individuals (as ‘donors’ of help) to act for the good of copies of their genes residing in close kin (‘recipients’). I propose however, that natural selection should particularly favour helping behaviours directed at those recipient kin who have the highest relative probability of being the vehicle for a remarkably adaptive newly mutant gene, weighted by the proportion of genes shared with the donor. According to this ‘adaptive-genetic-novelty-rescue’ (AGNR) hypothesis, these favoured vehicles for shared gene copies are more likely to involve direct descendants (e.g. offspring) than other close kin from one's collateral lineage (e.g. siblings), even when the donor (e.g. a father) shares fewer genes with an offspring (e.g. a son) than with a sibling (e.g. a brother).     

我的驯鹿,我的梦想——玛丽亚·索的诉说

一个不足200人的群体,一群不足800头的驯鹿,得到了政府的大力扶持,却依然在传统与现代的夹缝中徘徊。让我们倾听他们从山林里发出的微弱声音,跟他们一起思考:传统和现代,先进和落后……     

Mother-offspring conflict and interference at mother's mating inMacaca fascicularis

Theory suggests that it is in the interest of an infant to garner more care than its mother is selected to provide and that a rival sibling would curtail care from the mother. Thus delayed conception in the mother would be of advantage to the infant. One method of achieving this result would be to interfere with the mother's potential matings. To test this theory, the conflict between mothers and their infants in relation to maximizing inclusive fitness has been studied inMacaca fascicularis and infant interference has been observed. Focal animal samples were taken on 8 mothers and their 13 infants. Interactions analyzed were those between the mother and (1) an adult male, (2) her infant, (3) an adult female, (4) her infant and an adult male, (5) her infant and an adult female. Only explicit behaviours were analyzed. The infant's interference was found to be significantly related to its mother's mating, and this produced a deterring effect on the male. Infants did not interfere with any female's matings other than those of their mother. The interference was related to the number of mother-male contacts. In mothers that did subsequently conceive, infant interference at mating increased up to the mother's conception date and decreased thereafter. By contrast to the infants direct method, mothers approached the conflict indirectly. There were significantly more contacts and mounts with males in their infant's absence, they reacted negatively to their infant only when it had interfered, they were more lenient in the presence of an adult female than with an adult male, and they avoided their infant's presence at mother-male contacts. No significant sex bias in interference or the number of contacts with mother-male pairs has been found. There are indications of a sibship pattern of interference.     

Human foetuses learn odours from their pregnant mother's diet

Olfactory responsiveness was assessed in 24 neonates born to mothers who had or had not consumed anise flavour during pregnancy. Both groups of infants were followed-up for behavioural markers of attraction and aversion when exposed to anise odour and a control odour immediately after birth and on day 4. Infants born to anise-consuming mothers evinced a stable preference for anise odour over this period, whereas those born to anise non-consuming mothers displayed aversion or neutral responses. This study provides the first clear evidence that through their diet human mothers influence the hedonic polarity of their neonates' initial olfactory responses. The findings have potential implications for the early mother-to-infant transmission of chemosensory information relative to food and addictive products.