MALADAPTED GENE COMPLEXES WITHIN POPULATIONS OF THE INTERTIDAL COPEPOD TIGRIOPUS CALIFORNICUS?

The prevalence of F2 hybrid breakdown in interpopulation crosses of the marine copepod Tigriopus californicus can be explained by disruption of coadapted gene complexes. This study further dissects the nature of hybrid gene interactions, revealing that parental populations may also harbor maladapted gene complexes. Diagnostic molecular markers (14) were assayed in reciprocal F2 hybrids to test for gene interactions affecting viability. Results showed some evidence of nuclear–nuclear coadaptation. Although there were no significant examples of pairwise linkage disequilibrium between physically unlinked loci, one of the two reciprocal crosses did show an overall excess of parental double homozygotes and an overall dearth of nonparental double homozygotes. In contrast, the nuclear–cytoplasmic data showed a stronger tendency toward maladaptation within the specific inbred lines used in this study. For three out of four loci with significant frequency differences between reciprocal F2, homozygotes were favored on the wrong cytoplasmic background. A separate study of reciprocal backcross hybrids between the same two populations (but different inbred lines) revealed faster development time when the full haploid nuclear genome did not match the cytoplasm. The occurrence of such suboptimal gene complexes may be attributable to effects of genetic drift in small, isolated populations.     

IS HIV SHORT‐SIGHTED? INSIGHTS FROM A MULTISTRAIN NESTED MODEL

An important component of pathogen evolution at the population level is evolution within hosts. Unless evolution within hosts is very slow compared to the duration of infection, the composition of pathogen genotypes within a host is likely to change during the course of an infection, thus altering the composition of genotypes available for transmission as infection progresses. We develop a nested modeling approach that allows us to follow the evolution of pathogens at the epidemiological level by explicitly considering within‐host evolutionary dynamics of multiple competing strains and the timing of transmission. We use the framework to investigate the impact of short‐sighted within‐host evolution on the evolution of virulence of human immunodeficiency virus (HIV), and find that the topology of the within‐host adaptive landscape determines how virulence evolves at the epidemiological level. If viral reproduction rates increase significantly during the course of infection, the viral population will evolve a high level of virulence even though this will reduce the transmission potential of the virus. However, if reproduction rates increase more modestly, as data suggest, our model predicts that HIV virulence will be only marginally higher than the level that maximizes the transmission potential of the virus.     

MANDATORY HIV TESTING IN PREGNANCY: IS THERE EVER A TIME?

Despite recent advances in ways to prevent transmission of HIV from a mother to her child during pregnancy, infants continue to be born and become infected with HIV, particularly in southern Africa where HIV prevalence is the highest in the world. In this region, emphasis has shifted from voluntary HIV counselling and testing to routine testing of women during pregnancy. There have also been proposals for mandatory testing. Could mandatory testing ever be an option, even in high‐prevalence settings? Many previous examinations of mandatory testing have dealt with it in the context of low HIV prevalence and a well‐resourced health care system. In this discussion, different assumptions are made. Within this context, where mandatory testing may be a strategy of last resort, the objections to it are reviewed. Special attention is paid in the discussion to the entrenched vulnerability of women in much of southern Africa and how this contributes to both HIV prevalence and ongoing challenges for preventing HIV transmission during pregnancy. While mandatory testing is ethically plausible, particularly when coupled with guaranteed access to treatment and care, the discussion argues that the moment to employ this strategy has not yet come. Many barriers remain for pregnant women in terms of access to testing, treatment and care, most acutely in the southern African setting, despite the presence of national and international human rights instruments aimed at empowering women and removing such barriers. While this situation persists, mandatory HIV testing during pregnancy cannot be justified.     

IS PAYMENT A BENEFIT?

What I call ‘the standard view’ claims that IRBs should not regard financial payment as a benefit to subjects for the purpose of risk/benefit assessment. Although the standard view is universally accepted, there is little defense of that view in the canonical documents of research ethics or the scholarly literature. This paper claims that insofar as IRBs should be concerned with the interests and autonomy of research subjects, they should reject the standard view and adopt ‘the incorporation view.’ The incorporation view is more consistent with the underlying soft‐paternalist justification for risk‐benefit assessment and demonstrates respect for the autonomy of prospective subjects. Adoption of the standard view precludes protocols that advance the interests of subjects, investigators, and society. After considering several objections to the argument, I consider several arguments for the standard view that do not appeal to the interests and autonomy of research subjects.     

HOW DOES EVOLUTIONARY VARIATION IN BASAL METABOLIC RATES ARISE? A STATISTICAL ASSESSMENT AND A MECHANISTIC MODEL

Metabolic rates are related to the pace of life. Hence, research into their variability at global scales is of vital importance for several contemporary theories in physiology, ecology, and evolution. Here we evaluated the effect of latitude, climate, primary productivity, habitat aridity, and species trophic habits, on mass‐independent basal metabolic rates (BMRs) for 195 rodent species. The aims of this article were twofold. First, we evaluated the predictive power of different statistical models (via a model selection approach), using a dimensional reduction technique on the exogenous factor matrix to achieve a clear interpretation of the selected models. Second, we evaluated three specific predictions derived from a recently proposed hypothesis, herein called the “obligatory heat” model (OHM), for the evolution of BMR. Obtained results indicate that mean/minimum environmental temperature, rainfall/primary productivity and, finally, species trophic habits are, in this order, the major determinants of mass‐independent BMR. Concerning the mechanistic causes behind this variation, obtained data agree with the predictions of the OHM: (1) mean annual environmental temperature was the best single predictor of residual variation in BMR, (2) herbivorous species have greater mass‐independent metabolic rates, and tend to be present at high‐latitude cold environments, than species in other trophic categories.     

WHAT IS IT TO BE A DAUGHTER? IDENTITIES UNDER PRESSURE IN DEMENTIA CARE

This article concentrates on the care for people who suffer from progressive dementia. Dementia has a great impact on a person’s well‐being as well as on his or her social environment. Dealing with dementia raises moral issues and challenges for participants, especially for family members. One of the moral issues in the care for people with dementia is centred on responsibilities; how do people conceive and determine their responsibilities towards one another? To investigate this issue we use the theoretical perspective of Margaret Walker. She states that ideas about identity play a crucial role in patterns of normative expectations with regard to the distribution of responsibilities in daily practices of care. The results of this study show how the identity of a family‐member is put under pressure and changes during her loved one’s illness that leads to difficulties and misunderstandings concerning the issue of responsibility. These results offer an insight into the complexities of actual practices of responsibility and highlight the importance for those caring for people with dementia of attending carefully to how they see themselves and how they see other people involved (Who am I? Who do I want to be for the other?). Answers to such questions show what people expect from themselves and from one another, and how they, at any rate, are distributing responsibilities in a given situation. Professional caregivers should take into account that family members might have different ideas about who they are and consequently about what their responsibilities are.