Phenotypic Heterogeneity in Tumor Progression, and Its Possible Role in the Onset of Cancer

Heterogeneity among isogenic cells/individuals has been known for at least 150 years. Even Mendel, working on pea plants, realized that not all tall plants were identical. However, Mendel was more interested in the discontinuous variation between genetically distinct individuals. The concept of environment dictating distinct phenotypes among isogenic individuals has since been shown to impact the evolution of populations in numerous examples at different scales of life. In this review, we discuss how phenotypic heterogeneity and its evolutionary implications exist at all levels of life, from viruses to mammals. In particular, we discuss how a particular disease condition (cancer) is impacted by heterogeneity among isogenic cells, and propose a potential role that phenotypic heterogeneity might play toward the onset of the disease.

Predicting Evolutionary Transitions in Tooth Complexity With a Morphogenetic Model

The extent to which evolutionary transitions are shaped by developmental bias remains poorly understood. Classically, morphological variation is assumed to be abundant and continuous, but if morphogenesis biases how traits vary than evolutionary transitions might follow somewhat predictable steps. Compared to other anatomical structures, teeth have an exceptional fossil record which documents striking evolutionary trajectories toward complexity. Using computer simulations of tooth morphogenesis, we examined how varying developmental parameters influenced transitions from morphologically simple to complex teeth. We find that as tooth complexity increases, development tends to generate progressively more discontinuous variation which could make the fine-tuning of dietary adaptation difficult. Transitions from simple to complex teeth required an early shift from mesiodistal to lateral cusp patterning which is congruent with patterns of dental complexification in early mammals. We infer that the contributions of primary enamel knot cells to secondary enamel knots which are responsible for patterning lateral cusps may have been an important developmental innovation in tribosphenic mammals. Our results provide evidence that development can bias evolutionary transitions and highlights how morphogenetic modelling can play an important role in building more realistic models of morphological character evolution.

Is the genus Potamophylax (Trichoptera: Limnephilidae) highly polymorphic?

The present deprived state of taxonomy gives no appropriate resources for taxonomists to apply more sophisticated phenomic tools and to carry out more appropriate population sampling. Without fine structure analysis of large population samples there is no hope to discover speciation traits and there is no chance to delineate young incipient sibling species with subtle but stable shape divergences. Phylogenetic species complexes of these incipient species are frequently mistaken with species polymorphism. However, historical polymorphism is a sympatric phenomenon based on discontinuous variation inside a panmictic population and not between geographically isolated populations. I continue to consider Potamophylax mista (Navas, 1918) a valid species following the evidence given by Oláh et al. (2013).

Heterogeneous Turbine Blade Modeling Based on Multi-Color Distance Field

In heterogeneous turbine blades, multiple materials can be synthesized to provide better properties than any single material. In this paper, a new method for turbine blade modeling toward reverse engineering, termed as multi-color distance field, is presented. In this method, the material field describing the material composition continuous or discontinuous variation is associated with the signed distance field describing the geometry model. The method allows the designers to design and optimize no only the geometry but also the material composition of an object. Moreover, both the geometry model and the material information can be easily sliced to manufacture for the object represented using the associated multi-color distance field.