Seven principles to rule them all

Coen offers a unified explanation of natural selection, development, learning and cultural change, based on seven fundamental principles: population variation, persistence, reinforcement, competition, cooperation, combinatorial richness and recurrence. I discuss whether all seven principles are justified, successfully fit the four processes, encompass life processes only, and have any strong explanatory import. I find each of these claims doubtful.     

One ring to rule them all: trafficking of heme and heme synthesis intermediates in the metazoans

The appearance of heme, an organic ring surrounding an iron atom, in evolution forever changed the efficiency with which organisms were able to generate energy, utilize gasses and catalyze numerous reactions. Because of this, heme has become a near ubiquitous compound among living organisms. In this review we have attempted to assess the current state of heme synthesis and trafficking with a goal of identifying crucial missing information, and propose hypotheses related to trafficking that may generate discussion and research. The possibilities of spatially organized supramolecular enzyme complexes and organelle structures that facilitate efficient heme synthesis and subsequent trafficking are discussed and evaluated. Recently identified players in heme transport and trafficking are reviewed and placed in an organismal context. Additionally, older, well established data are reexamined in light of more recent studies on cellular organization and data available from newer model organisms. This article is part of a Special Issue entitled: Cell Biology of Metals.     

Bayesian random local clocks,or one rate to rule them all

Background  

Relaxed molecular clock models allow divergence time dating and "relaxed phylogenetic" inference, in which a time tree is estimated in the face of unequal rates across lineages. We present a new method for relaxing the assumption of a strict molecular clock using Markov chain Monte Carlo to implement Bayesian modeling averaging over random local molecular clocks. The new method approaches the problem of rate variation among lineages by proposing a series of local molecular clocks, each extending over a subregion of the full phylogeny. Each branch in a phylogeny (subtending a clade) is a possible location for a change of rate from one local clock to a new one. Thus, including both the global molecular clock and the unconstrained model results, there are a total of 2^2n-2 possible rate models available for averaging with 1, 2, ..., 2n - 2 different rate categories.     

One size fits all: a surgical technique for the correction of all types of prominent ears

Patient satisfaction after surgery to correct the prominent ear relates to the degree of retroposition of the ear. Angular breaks in the cartilage seen with other cartilage-transecting procedures (and even after conchal resections), which are noticed by patients, led to the development of this technique. It is an easy operative technique that may be modified to suit all prominent ears, including the constricted cup ear, and it does not leave any sharp, visible ridges in the region of the anti-helix or concha. The procedure combines and modifies a number of techniques that have been described previously, which allows more flexibility in the treatment of this deformity.     

On the use of the Price equation

This paper distinguishes two categories of questions that the Price equation can help us answer. The two different types of questions require two different disciplines that are related, but nonetheless move in opposite directions. These disciplines are probability theory on the one hand and statistical inference on the other. In the literature on the Price equation this distinction is not made. As a result of this, questions that require a probability model are regularly approached with statistical tools. In this paper, we examine the possibilities of the Price equation for answering questions of either type. By spending extra attention on mathematical formalities, we avoid the two disciplines to get mixed up. After that, we look at some examples, both from kin selection and from group selection, that show how the inappropriate use of statistical terminology can put us on the wrong track. Statements that are 'derived' with the help of the Price equation are, therefore, in many cases not the answers they seem to be. Going through the derivations in reverse can, however, be helpful as a guide how to build proper (probabilistic) models that do give answers.     

One ring to bind them. Septins and actin assembly

Septins are GTPases required for cytokinesis and other processes requiring spatial organization of the cell cortex, but their molecular functions in these processes are unknown. In this issue of Developmental Cell, Kinoshita et al. take an important step in elucidating the molecular functions of septins by developing an in vitro assay for septin assembly and exploring the relationship between mammalian septins and actin.     

Genes: philosophical analyses put to the test

This paper describes one complete and one ongoing empirical study in which philosophical analyses of the concept of the gene were operationalized and tested against questionnaire data obtained from working biologists to determine whether and when biologists conceive genes in the ways suggested. These studies throw light on how different gene concepts contribute to biological research. Their aim is not to arrive at one or more correct 'definitions' of the gene, but rather to map out the variation in the gene concept and to explore its causes and its effects.     

From aquatic science to ecosystem health: a philosophical perspective

The development of an ecosystem (social, economic, environmental) approach to water management is traced from its origins in the Great Lakes of North America. The focus on health and integrity of ecosystems is an outgrowth of the Lamarckian concept of The Biosphere as a global system of matter, life, and mind. The driving forces behind the development of an ecosystem approach have been negative feedback from excessive demotechnic growth and faith that we can maintain a healthy relationship with Mother Earth.     

Joseph Hooker: a philosophical botanist

The nineteenth-century British botanist, Joseph Dalton Hooker,was one of the people whose career became a model for that of the modern,professional scientist.However,he preferred to refer to himself as a philosophical botanist, rather than a professional. This paper explores the reasons for this choice,and analyses Hooker's imperial approach to plant classification, the consequences of which are still with us.