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Mitochondrial DNA (mtDNA) sequences from 686 wild and domestic pig specimens place the origin of wild boar in island Southeast Asia (ISEA), where they dispersed across Eurasia. Previous morphological and genetic evidence suggested pig domestication took place in a limited number of locations (principally the Near East and Far East). In contrast, new genetic data reveal multiple centers of domestication across Eurasia and that European, rather than Near Eastern, wild boar are the principal source of modern European domestic pigs.

Changes in the control of developmental gene expression patterns have been implicated in the evolution of animal morphology. However, the genetic mechanisms underlying complex morphological traits remain largely unknown. Here we investigated the molecular mechanisms that induce the pigmentation gene yellow in a complex color pattern on the abdomen of Drosophila guttifera . We show that at least five developmental genes may collectively activate one cis -regulatory module of yellow in distinct spot rows and a dark shade to assemble the complete abdominal pigment pattern of Drosophila guttifera . One of these genes, wingless , may play a conserved role in the early phase of spot pattern development in several species of the quinaria group. Our findings shed light on the evolution of complex animal color patterns through modular changes of gene expression patterns.

1. In vertebrates, bite force is a measure of whole organism performance that is associated with both cranial morphology and dietary ecology. Mechanistic studies of bite force production have identified morphological features associated with bite force, and linked bite force with diet, but this approach has rarely been used in mammals. 2. Mammals are a good system with which to investigate the function of the feeding apparatus because of the relative simplicity of their skulls and their high dietary diversity. Phyllostomid bats are one of the most trophically and morphologically diverse groups of mammals, but we know little about the relative importance of biomechanical variables in producing bite force or how these variables vary with diet. 3. We combined in vivo measurements of bite force with assessments of muscular and bony morphology to build and validate a model describing the mechanics of bite force production in 25 species of bats. We used this model to investigate how bats with different diets vary in biomechanical parameters that contribute to bite force. In addition to traditional dietary categories, we used a functional definition of diet that reflects the mechanical demands (hardness) of the food items in the natural diet. 4. Our model provided good predictions of in vivo bite forces and highlighted behavioural variation that is inherent in the in vivo data. The temporalis generates the highest moment about the temporomandibular joint (TMJ) axis, but the moment generated by the masseter is the most important variable in explaining variation among species. The dietary classification based on the hardness of the diet was more effective than traditional dietary categories in describing biomechanical differences among groups. The temporalis generated the highest proportion of the moment about the TMJ axis in species with very hard and hard diets, the masseter was most important for species with soft diets, and the medial pterygoid was most important for species with liquid diets. 5. Our results highlight the utility of combining a modelling approach with in vivo data when conducting ecomorphological studies, and the importance of ecological classifications that reflect functional importance of performance traits.

Phenotypic switching between 2 opposing cellular states is a fundamental aspect of biology, and fungi provide facile systems to analyze the interactions between regulons that control this type of switch. A long-standing mystery in fungal pathogens of humans is how thermally dimorphic fungi switch their developmental form in response to temperature. These fungi, including the subject of this study, Histoplasma capsulatum, are temperature-responsive organisms that utilize unknown regulatory pathways to couple their cell shape and associated attributes to the temperature of their environment. H. capsulatum grows as a multicellular hypha in the soil that switches to a pathogenic yeast form in response to the temperature of a mammalian host. These states can be triggered in the laboratory simply by growing the fungus either at room temperature (RT; which promotes hyphal growth) or at 37 °C (which promotes yeast-phase growth). Prior worked revealed that 15% to 20% of transcripts are differentially expressed in response to temperature, but it is unclear which transcripts are linked to specific phenotypic changes, such as cell morphology or virulence. To elucidate temperature-responsive regulons, we previously identified 4 transcription factors (required for yeast-phase growth [Ryp]1-4) that are required for yeast-phase growth at 37 °C; in each ryp mutant, the fungus grows constitutively as hyphae regardless of temperature, and the cells fail to express genes that are normally induced in response to growth at 37 °C. Here, we perform the first genetic screen to identify genes required for hyphal growth of H. capsulatum at RT and find that disruption of the signaling mucin MSB2 results in a yeast-locked phenotype. RNA sequencing (RNAseq) experiments reveal that MSB2 is not required for the majority of gene expression changes that occur when cells are shifted to RT. However, a small subset of temperature-responsive genes is dependent on MSB2 for its expression, thereby implicating these genes in the process of filamentation. Disruption or knockdown of an Msb2-dependent mitogen-activated protein (MAP) kinase (HOG2) and an APSES transcription factor (STU1) prevents hyphal growth at RT, validating that the Msb2 regulon contains genes that control filamentation. Notably, the Msb2 regulon shows conserved hyphal-specific expression in other dimorphic fungi, suggesting that this work defines a small set of genes that are likely to be conserved regulators and effectors of filamentation in multiple fungi. In contrast, a few yeast-specific transcripts, including virulence factors that are normally expressed only at 37 °C, are inappropriately expressed at RT in the msb2 mutant, suggesting that expression of these genes is coupled to growth in the yeast form rather than to temperature. Finally, we find that the yeast-promoting transcription factor Ryp3 associates with the MSB2 promoter and inhibits MSB2 transcript expression at 37 °C, whereas Msb2 inhibits accumulation of Ryp transcripts and proteins at RT. These findings indicate that the Ryp and Msb2 circuits antagonize each other in a temperature-dependent manner, thereby allowing temperature to govern cell shape and gene expression in this ubiquitous fungal pathogen of humans.

External morphology has been shown to influence predation and locomotion of decapod larvae and is, therefore, directly related to their ability to survive and disperse. The first goal of this study was to characterize first-stage blue crab zoeal morphology and its variability across larval broods to test whether inter-brood differences in morphology exist. The second was to identify possible correlations between maternal characteristics and zoeal morphology. The offspring of 21 individuals were hatched in the laboratory, photographed, and measured. Zoeae exhibited substantial variability, with all metrics showing significant inter-brood differences. The greatest variability was seen in the zoeal abdomen, rostrum, and dorsal spine length. A principal component analysis showed no distinct clustering of broods, with variation generally driven by larger zoeae. Using observed morphology, models of drag induced by swimming and sinking also showed significant inter-brood differences, with a maximum twofold difference across broods. In contrast to trends in other decapod taxa, maternal characteristics (female carapace width and mass and egg sponge volume and mass) are not significant predictors of zoeal morphology. These results suggest that brood effects are present across a wide range of morphological characteristics

The adoption of the horse for chariots, wagons and riding had a major impact on human societies, but it has proved difficult to reliably identify early domesticated horses in the archaeological record. This comparative study of equine palaeopathology addresses the problem by analysing wild and domestic horses used for traction or riding. Osteological changes to the skull appear to be the result of mechanical and physiological stress from the use of horses for transport. The results are applied to archaeological examples from the Deer Stone-Khirigsuur Complex of Bronze Age Mongolia (1300–700 BC) and show that those horses were probably bridled and used for transport.

1. On thermally stressful rocky shores, small, slow-moving ectotherms such as limpets exhibit morphological characteristics such as high-spired and heavily ridged shells which may reduce the likelihood of reaching stressful or lethal body temperatures. 2. The effects of shell height and shell surface area on predicted limpet body temperatures were tested with a previously developed heat budget model. The model was parameterized with morphological data from three species (Lottia gigantea, Patella vulgata and Siphonaria gigas), which differ dramatically in their morphology and in the body temperatures they are likely to reach in the field. 3. Limpet models and standard cones with higher height : length ratios lost heat to convection more readily than models with lower spired shells. 4. Heavily ridged shells lost heat to convection more readily than smoother shells, but this effect was only pronounced at high wind velocities. 5. When the heat budget model parameters were applied to a real environmental data set, the model predicts that maximum body temperatures and cumulative thermal stress vary among species. These differences are related primarily to the height : length ratio of the shell, and to a lesser extent to the presence of ridges. 6. These results suggest that some intra- and interspecific variation in limpet morphology may be phenotypic or evolutionary responses to variation in environmental temperatures. Our findings are supported by observed patterns of limpet morphological variation across natural thermal gradients.

Water temperature influences the behavior and distribution patterns of both larval and adult American lobster Homarus americanus. However, very little is known about the responses of juvenile lobsters. The juvenile life stage is a critical period; high levels of mortality, combined with specific behavioral responses, can disconnect larval settlement from patterns of abundance of adults. We assessed behavioral thermoregulation in juvenile lobsters, and determined how thermal preferences can be altered by the presence of shelter and food. Juvenile lobsters avoided temperatures higher than 20 °C and lower than 8 °C, and had a mean temperature preference of 16.2 ± 1 °C. This preference was unaffected by prior acclimation, origin (laboratory-raised or wild), or size. When the animals were subjected to a temperature change (5–20 °C), activity rates peaked at 15 °C, and remained stable thereafter. Activity rates did not change when a shelter was added. The addition of food resulted in an increase in activity associated with food handling. When juvenile lobsters were offered a choice between temperature, shelter, and food, they always chose the environment with a shelter, even when it was in a thermally unfavorable temperature. Juveniles also spent more time in a thermally unfavorable environment when food was present; however, acquisition of a shelter was prioritized over food. Although juveniles had a similar thermal preference to adults, they are more vulnerable to predation; the innate shelter-seeking behavior of juveniles overrode their thermal preference. While temperature is an important environmental factor affecting the physiology, distribution, and growth of aquatic ectotherms, our findings suggest that trade-off behaviors occur in order to maintain optimal fitness and survival of the individual.