Darwin and Mendel: who was the pioneer of genetics?

Although Mendel is now widely recognized as the founder of genetics, historical studies have shown that he did not in fact propose the modern concept of paired characters linked to genes, nor did he formulate the two "Mendelian laws" in the form now given. Furthermore, Mendel was accused of falsifying his data, and Mendelism has been met with scepticism because of its failure to provide scientific explanation for evolution, to furnish a basis for the process of genetic assimilation and to explain the inheritance of acquired characters, graft hybridization and many other facts. Darwin was the first to clearly describe almost all genetical phenomena of fundamental importance, and was the first to present a developmental theory of heredity--Pangenesis, which not only greatly influenced many subsequent theories of inheritance, particularly those of de Vries, Galton, Brooks and Weismann, but also tied all aspects of variation, heredity and development together, provided a mechanism for most of the observable facts, and is supported by increasing evidence. It has also been indicated that Darwin's influence on Mendel, primarily from The Origin, is evident. The word "gene" was derived from "pangen", itself a derivative of "Pangenesis" which Darwin had coined. It seems that Darwin should have been regarded as the pioneer, if not of transmissional genetics, of developmental genetics and molecular genetics.     

Breaching the basement membrane: who, when and how?

The basement membrane (BM), a specialized network of extracellular matrix macromolecules, surrounds epithelial, endothelial, muscle, fat and nerve cells. During development, immune surveillance and disease states ranging from cancer to fibrosis, host cells penetrate the BM by engaging tissue-invasive programs, the identity of which remain largely undefined. Although it is commonly assumed that all cells employ similar mechanisms to cross BM barriers, accumulating evidence indicates that cells might selectively mobilize protease-dependent or -independent invasion programs. New data indicate that protease-dependent transmigration is largely reliant on a group of membrane-anchored metalloenzymes, termed the membrane-type matrix metalloproteinases, which irreversibly remodel BM structure. By contrast, mechanisms that enable protease-independent transmigration remain undefined and potentially involve the reversible disassembly of the BM network. Further characterization of the molecular mechanisms underlying BM transmigration should provide important insights into pathophysiologic tissue remodeling events and also enable the development of novel therapeutics.     

Virulence and resistance in malaria: who drives the outcome of the infection?

Theoretical and experimental studies have established the dynamic nature of virulence and that, like all traits, it has evolved. Understanding parasite evolution offers a conceptual framework for diverse fields and can contribute greatly to decision-making in disease control. Recently, Grech et al. investigated the effects of host genotype-by-parasite genotype interactions on the expression of virulence in an artificial rodent-malaria system. They found that both parasite and host effects explained most of the variance in the virulence, resistance and transmission potential. These findings are a major contribution to the emerging debate on the pros and cons of a coevolutionary approach of virulence evolution; they also hold great potential for more effective control strategies.     

Schistosome monogamy: who,how, and why?

Schistosomes represent a unique animal model for comparative analyses of monogamy. Indeed, schistosomes are classified at the lowest taxonomical level of monogamous species and lack complex social interactions, which could alter our understanding of their unusual mating system. Elements discussed here include the fact that monogamy in schistosomes could be an ancestral state between hermaphroditism and polygyny or polygynandry and the occurrence of mate changes. In addition, hypotheses are proposed to explain monogamy in schistosomes (e.g. female dispersion, the need for paternal care, oviposition site limitation or aggressiveness, and mate guarding). We also propose future experimental and analytical approaches to improve our understanding of the schistosomes' mating system.     

Speciation: don't fly and diversify?

Loss of flight in Japanese carrion beetles is correlated with greater population subdivision and higher speciation rate. This reveals the complex relationship of trait evolution with dispersal power, range size and diversification.     

The Lengthening of a Giant Protein: When, How, and Why?

Subcommissural organ (SCO)-spondin is a giant glycoprotein of more than 5000 amino acids found in Vertebrata, expressed in the central nervous system and constitutive of Reissner’s fiber. For the first time, in situ hybridization performed on zebrafish (Danio rerio) embryos shows that the gene encoding this protein is expressed transitionally in the floor plate, the ventral midline of the neural tube, and later in the diencephalic third ventricle roof, the SCO. The modular organization of the protein in Echinodermata (Strongylocentrotus purpuratus), Urochordata (Ciona savignyi and C. intestinalis), and Vertebrata (Teleostei, Amphibia, Aves and Mammalia) is also described. As the thrombospondin type 1 repeat motifs represent an increasingly large part of the protein during Deuterostomia evolution, the duplication mechanisms leading to this complex organization are examined. The functional significance of the particularly well-preserved arrangement of the series of SCO-spondin repeat motifs and thombospondin type 1 repeats is discussed. Electronic Supplementary Material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Parallel import and pacemakers: who pays the ferryman?

Fifty years after its introduction in clinical cardiology, artificial pacing for patients with bradyarrhythmias has made a huge leap forward.1 The development from bulky, simple fixed-rate pacemakers to small, complex, multi-programmable devices paralleled the vast technological achievements of the second half of the 20th century. In the late 1990s hope emerged even for patients with severe heart failure, with the introduction of biventricular pacing which resulted in an additional class I indication according to the recent guideline of the European Society of Cardiology.2 Consequently, the number of implantations has steadily increased, resulting in more than 10,000 implantations (both first implants and replacements) in the Netherlands in 2007.     

Neuronal variability: noise or part of the signal?

Sensory, motor and cortical neurons fire impulses or spikes at a regular, but slowly declining, rate in response to a constant current stimulus. Yet, the intervals between spikes often vary randomly during behaviour. Is this variation an unavoidable effect of generating spikes by sensory or synaptic processes ('neural noise') or is it an important part of the 'signal' that is transmitted to other neurons? Here, we mainly discuss this question in relation to sensory and motor processes, as the signals are best identified in such systems, although we also touch on central processes.     

Metabolic and hedonic drives in the neural control of appetite: who is the boss?

Obesity is on the rise in all developed countries, and a large part of this epidemic has been attributed to excess caloric intake, induced by ever present food cues and the easy availability of energy dense foods in an environment of plenty. Clearly, there are strong homeostatic regulatory mechanisms keeping body weight of many individuals exposed to this environment remarkably stable over their adult life. Other individuals, however, seem to eat not only because of metabolic need, but also because of excessive hedonic drive to make them feel better and relieve stress. In the extreme, some individuals exhibit addiction-like behavior toward food, and parallels have been drawn to drug and alcohol addiction. However, there is an important distinction in that, unlike drugs and alcohol, food is a daily necessity. Considerable advances have been made recently in the identification of neural circuits that represent the interface between the metabolic and hedonic drives of eating. We will cover these new findings by focusing first on the capacity of metabolic signals to modulate processing of cognitive and reward functions in cortico-limbic systems (bottom-up) and then on pathways by which the cognitive and emotional brain may override homeostatic regulation (top-down).     

ROS signaling in the hypersensitive response: When,where and what for?

Plants generally react to the attack of non-host and incompatible host microorganisms by inducing pathogenesis-related (PR) genes and localised cell death (LCD) at the site of infection, a process collectively known as the hypersensitive response (HR). Reactive oxygen species (ROS) are generated in various sub-cellular compartments shortly after pathogen recognition, and proposed to cue subsequent orchestration of the HR. Although apoplast-associated ROS production by plasma membrane NADPH oxidases have been most thoroughly studied, recent observations suggest that ROS are generated in chloroplasts earlier in the response and play a key role in execution of LCD. A model is presented in which the initial outcome of successful pathogen detection is ROS accumulation in plastids, likely mediated by mitogen-activated protein kinases and caused by dysfunction of the photosynthetic electron transport chain. ROS signaling is proposed to spread from plastids to the apoplast, through the activation of NADPH oxidases, and from there to adjacent cells, leading to suicidal death in the region of attempted infection.Key words: biotic stress, chloroplasts, flavodoxin, hypersensitive response (HR), reactive oxygen species (ROS), ROS signaling     

Decoding ARE-mediated decay: is microRNA part of the equation?

Messenger ribonucleic acids (mRNAs) containing adenine/uridine-rich elements (AREs) in their 3' untranslated region are particularly labile, allowing for the regulation of expression for growth factors, oncoproteins, and cytokines. The regulators, effectors, and location of ARE-mediated decay (AMD) have been investigated by many groups in recent years, and several links have been found between AMD and microRNA-mediated decay. We highlight these similarities, along with recent advances in the field of AMD, and also mention how there is still much left unknown surrounding this specialized mode of mRNA decay.     

‘It's a part of me,I feel naked without it': choice,agency and identity for Muslim women who wear the niqab

In the context of heightened suspicion and anti-Muslim stereotypes in a post-9/11 and 7/7 era, Muslim women who wear the niqab (face veil) are stigmatized, criminalized and marked as ‘dangerous’ to British/Western values. While the wearing of the niqab has elicited a good deal of media, political and public debates, little attention has been paid to the opinions of Muslim women who wear it. Drawing on individual and focus group interviews with Muslim women who wear the niqab in the UK, this article places at the centre of the debate the voices of those women who do wear it, and explores their reasons for adopting it. The findings show that the wearing of the niqab emerges as a personal choice, an expression of religious piety, public modesty and belonging to the ‘ummah’. It is also perceived as a form of agency, and non-conformity to Western consumerist culture and lifestyle.