Doing something about tuberculosis

The phenomenal success public health officials enjoyed in controlling tuberculosis (TB) in developed countries has not been mirrored in developing countries, where TB still accounts for 25% of preventable deaths in adults. The fact that there are 8 million new cases each year (95% in developing countries) and 3 million deaths (98% in developing countries) led to the 1993 declaration by the World Health Organization (WHO) that TB poses a global emergency. Because TB is predominantly a disease of impoverished people, indifference has led to the fallacious and naive view that eradication of TB simply requires socioeconomic development. In response to this indifference, the WHO is promoting a "Stop TB--Use DOTS" campaign. DOTS, a strategy based on directly observed therapy, also requires government commitment, a regular supply of drugs, effective diagnoses, and an audit of the efficacy of the strategy. While the treatment of TB is among the most cost-effective of all medical interventions in terms of years of healthy life saved, the DOTS campaign requires a considerable dedication of funds. Renewed interest in TB is leading the US and the UK to increase support for control programs. In addition, a new UK-based charity, "TB Alert," hopes to play a major role in advocating for political commitment to and funding for TB control.     

Morphological differentiation in Carduelis finches: Adaptive vs. constraint models

In this study we show that morphological diversification in the avian genus Carduelis (Carduelinae) has to a large extent been conservative. Using multivariate methods, we found only minor deviations from the common (ancestral) body-plan. In particular, variation in bill morphology was found to be more conservative than variation in other parts of the body. We argue that constraint models of population differentiation can successfully account for the variation in bill morphology in this genus, but are less successful in accounting for variation in other traits. This can be interpreted as a result of long-term overall stabilizing selection for a certain bill morphology which is related to the way the birds open seeds. A trait combination that is adaptive on the evolutionary time scale may thus act as a constraint on changes in bill morphology on the microevolutionary scale. We conclude that the most parsimonious explanation for low divergence in bill morphology in this genus is that all species have retained the ancestral bill morphology. This may mean that each species chooses its environment rather than being moulded by it. This argument seems to apply to bill morphology, but other traits studied in this genus appear to have evolved in a less constrained fashion. A new index of morphometric integration is introduced to describe covariance structures.     

Thermometers: something for statistical geneticists to think about

In human genetics, we measure the strength of statistical evidence using a variety of maximized likelihood ratios, LODs, and empirical p values. I argue here that these statistics have highly undesirable properties as evidence measures when applied to complex disorders. Among other deficiencies, I show that when following up on an interesting finding, they will tend to erroneously indicate diminished evidence as more data are considered (e.g., the LOD will tend to go down at a linked locus as the sample size increases). This violates a fundamental assumption underlying standard linkage and association designs in which we first scan the genome for our best signals, and then follow up at those genomic positions with additional data. I argue here for a coherent theoretical approach to formalizing statistical evidence measures, and derive a set of minimal requirements that any evidence measure should meet, drawing heavily on an analogy with the thermometer. I speculate that measures of evidence that come closer to meeting these requirements will do a better job of finding and characterizing genes, and I propose an alternative evidence metric as a step in this direction.     

Adaptive, pre-adaptive and non-adaptive components of radiations in ancient lakes: a review

Ancient lakes are ideal model systems for evolutionary studies, as they hold hundreds of endemic species. The vast majority of these still occur in the cradle of their origin. We distinguish three different modes of speciation (allo-, para- and sympatric) which have occurred in these habitats. Although radiations from ancient lakes are generally assumed to be adaptive, we cannot fully support this point of view, because non-adaptive radiations also appear to be common, for example through chromosomal changes, hybridization or sexual selection. Even in supposedly adaptive cladogenesis, e.g. as concerns the presumed trophic adaptations of cichlid (Pisces) mouth and tooth shapes, both adaptive and non-adaptive components are acting. Distribution patterns of non-marine ostracods (Crustacea) within and outside of ancient lakes indicate that sexual reproduction might be an additional requirement for successful radiations in ancient lakes, at least in certain groups. This can best be understood by invoking ecology-based hypotheses on the evolutionary superiority of sexual reproduction such as Fisher–Muller accelerated evolution and the Tangled Bank.     

Genomic susceptibility-testing and pregnancy: something old, something new

This essay explores how testing for common and complex or genomic, as opposed to genetic, susceptibility to deep vein thrombosis both challenges and consolidates old social discourses on genes, gender and pregnancy. The nexus between genetics and reproduction usually crystallizes in the moral dilemma of selective termination. This essay examines online discussion among women with a genomic predisposition to deep vein thrombosis, which is associated with miscarriage and stillbirth. It explores the women's exchanges on what to 'do' in order to safely carry to term a foetus, which may always also have the genomic susceptibility. Interpreting DNA not in terms of predicting fate but of suggesting how to modify one's behaviour in order to give and care for life blunts its eugenic edge. However, this interpretation also shoulders discussants with the complicated and laborious responsibility of modifying themselves, their life styles and the life styles of their families--all of which falls within women's traditional labour of love in the privatized age of bioindividuality.     

Chimpanzee behavior: there's no place like home

During times of crisis, humans often seek the comforts of home. New observations indicate that, during periods of food shortage, male chimpanzees behave in similar fashion by returning to the areas they occupied with their mothers in youth.     

There's something about a fair split: intentionality moderates context-based fairness considerations in social decision-making

Fairness considerations are a strong motivational force in social decision-making. Here, we investigated the role of intentionality in response to unfair offers in the Ultimatum Game by manipulating both proposers' degree of control over the selection of offers and the context pertaining to the outcomes of offers proposers can choose from. As a result, the design enabled us to disentangle intention- and context-based decision-making processes. Rejection rates were higher when an unfair offer was intentionally chosen over a fair alternative than when it was chosen by the computer, outside proposers' control. This finding provides direct evidence for intention-based decision-making. Also, rejection rates in general were sensitive to the context in which an offer was made, indicating the involvement of both intention- and context-based processes in social decision-making. Importantly, however, the current study highlights the role of intention-based fairness considerations in basic decision-making situations where outcomes are explicitly stated and thus easy to compare. Based on these results, we propose that fairness can be judged on different, but additive levels of (social-) cognitive processing that might have different developmental trajectories.     

GEIGER: investigating evolutionary radiations

SUMMARY: GEIGER is a new software package, written in the R language, to describe evolutionary radiations. GEIGER can carry out simulations, parameter estimation and statistical hypothesis testing. Additionally, GEIGER's simulation algorithms can be used to analyze the statistical power of comparative approaches. AVAILABILITY: This open source software is written entirely in the R language and is freely available through the Comprehensive R Archive Network (CRAN) at http://cran.r-project.org/.