scholarly journals Impact of transition to a subterranean lifestyle on morphological disparity and integration in talpid moles (Mammalia, Talpidae)

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Gabriele Sansalone ◽  
Paolo Colangelo ◽  
Anna Loy ◽  
Pasquale Raia ◽  
Stephen Wroe ◽  
...  
Keyword(s):  
Evolutionary Biology ◽  
Morphological Variability ◽  
Phenotypic Integration ◽  
Phenotypic Traits ◽  
Phenotypic Evolution ◽  
Morphological Disparity ◽  
Morphological Diversification ◽  
Phylogenetic Conservatism ◽  
Selective Forces ◽  
Subterranean Species

Abstract Background Understanding the mechanisms promoting or constraining morphological diversification within clades is a central topic in evolutionary biology. Ecological transitions are of particular interest because of their influence upon the selective forces and factors involved in phenotypic evolution. Here we focused on the humerus and mandibles of talpid moles to test whether the transition to the subterranean lifestyle impacted morphological disparity and phenotypic traits covariation between these two structures. Results Our results indicate non-subterranean species occupy a significantly larger portion of the talpid moles morphospace. However, there is no difference between subterranean and non-subterranean moles in terms of the strength and direction of phenotypic integration. Conclusions Our study shows that the transition to a subterranean lifestyle significantly reduced morphological variability in talpid moles. However, this reduced disparity was not accompanied by changes in the pattern of traits covariation between the humerus and the mandible, suggesting the presence of strong phylogenetic conservatism within this pattern.

Deconstructing and reconstructing joint hypermobility on an evo-devo perspective

Rheumatology ◽  
2021 ◽  
Author(s):  
Marco Castori
Keyword(s):  
Evolutionary Biology ◽  
Phenotypic Variability ◽  
Morphological Variability ◽  
Complex Trait ◽  
Joint Hypermobility ◽  
Integration Model ◽  
Ehlers Danlos Syndrome ◽  
Evo Devo ◽  
Derivatives Of ◽  
Continuous Traits

Abstract Joint hypermobility is a common characteristic in humans. Its non-casual association with various musculoskeletal complaints is known and currently defined “the spectrum”. It includes hypermobile Ehlers–Danlos syndrome (hEDS) and hypermobility spectrum disorders (HSD). hEDS is recognized by a set of descriptive criteria, while HSD is the background diagnosis for individuals not fulfilling these criteria. Little is known about the aetiopathogenesis of the spectrum. It may be interpreted as a complex trait according to the integration model. Particularly, the spectrum is common in the general population, affects morphology, presents extreme clinical variability and is characterized by marked sex bias without a clear Mendelian or hormonal explanation. Joint hypermobility and the other hEDS systemic criteria are intended as qualitative derivatives of continuous traits of normal morphological variability. The need for a minimum set of criteria for hEDS diagnosis implies a tendency to co-vary of these underlying continuous traits. In evolutionary biology, such a co-variation (i.e. integration) is driven by multiple forces, including genetic, developmental, functional and environmental/acquired interactors. The aetiopathogenesis of the spectrum may be resolved by a deeper understanding of phenotypic variability, which superimposes on normal morphological variability.

scholarly journals Understanding the nature of wealth and its effects on human fitness

2011 ◽  
Vol 366 (1563) ◽  
pp. 344-356 ◽  
Author(s):  
Monique Borgerhoff Mulder ◽  
Bret A. Beheim
Keyword(s):  
Phenotypic Traits ◽  
Human Diversity ◽  
Material Wealth ◽  
Fitness Consequences ◽  
Model Selection Approach ◽  
Holistic Understanding ◽  
Selection Approach ◽  
Household Assets ◽  
Selective Forces ◽  
Specific Contribution

Studying fitness consequences of variable behavioural, physiological and cognitive traits in contemporary populations constitutes the specific contribution of human behavioural ecology to the study of human diversity. Yet, despite 30 years of evolutionary anthropological interest in the determinants of fitness, there exist few principled investigations of the diverse sources of wealth that might reveal selective forces during recent human history. To develop a more holistic understanding of how selection shapes human phenotypic traits, be these transmitted by genetic or cultural means, we expand the conventional focus on associations between socioeconomic status and fitness to three distinct types of wealth—embodied, material and relational. Using a model selection approach to the study of women's success in raising offspring in an African horticultural population (the Tanzanian Pimbwe), we find that the top performing models consistently include relational and material wealth, with embodied wealth as a less reliable predictor. Specifically, child mortality risk is increased with few household assets, parent nonresidency, child legitimacy, and one or more parents having been accused of witchcraft. The use of multiple models to test various hypotheses greatly facilitates systematic comparative analyses of human behavioural diversity in wealth accrual and investment across different kinds of societies.

The Intellectual Challenge of Morphological Evolution: A Case for Variational Structuralism

2014 ◽  
Author(s):  
Günter P. Wagner
Keyword(s):  
Developmental Biology ◽  
Evolutionary Biology ◽  
Morphological Evolution ◽  
Evolutionary Developmental Biology ◽  
Phenotypic Evolution ◽  
Developmental Variation ◽  
Core Idea ◽  
Intellectual Challenge

This chapter explores variational structuralism, whose core idea is that organisms and their parts play causal roles in shaping the patterns of phenotypic evolution. Drawing on the work of pioneers such as Ron Amundson, it discusses the conceptual incompatibilities between two styles of thinking in evolutionary biology: functionalism and structuralism. It proceeds by explaining the meaning of developmental types and structuralist concepts arising from macromolecular studies. It also examines facts and ideas about bodies, Rupert Riedl's theory of the “immitatory epigenotype,” and Neil Shubin and Pere Alberch's developmental interpretation of tetrapod limbs. Finally, it looks at the emergence of molecular structuralism and the enigma of developmental variation. The chapter argues that typology naturally emerged from the facts of evolutionary developmental biology and that it would be seriously problematic to try to avoid it.

Assessment

2003 ◽  
Author(s):  
Mary Jane West-Eberhard
Keyword(s):  
Evolutionary Biology ◽  
Developmental Plasticity ◽  
Phenotypic Traits ◽  
Phase Polymorphism ◽  
Aesthetic Sense ◽  
Adaptive Assessment ◽  
Important Barrier ◽  
Symbiotic Microorganism ◽  
Adaptive Developmental Plasticity ◽  
Adaptive Switch

A book on developmental plasticity needs a chapter on assessment, if only to show that adaptive environmental assessment occurs. Skepticism regarding the ability of nonhuman organisms to assess conditions well enough to make adaptive decisions has a long history in evolutionary biology, and it has been an important barrier to understanding the evolution of adaptive developmental plasticity. It is worth briefly reviewing this history in order to understand certain preconceptions about assessment that still persist. In the nineteenth century, critics of Darwin’s theory of sexual selection (Darwin, 1871) balked at the idea of an “aesthetic sense” in lowly creatures that would enable female choice of mates (representative papers are reprinted and discussed in Bajema, 1984). Later, the barrier persisted for other reasons. Even though naturalists routinely used the condition-appropriate expression of phenotypic traits to support adaptation hypotheses—a practice that assumes adaptive assessment of conditions as it is defined here—theoretically inclined biologists paid little attention to the question of facultatively expressed traits. Part of the difficulty lay in the problem of explaining how adaptive assessment could evolve within the framework of conventional genetics. Theodosius Dobzhansky, one of the twentieth century’s leading evolutionary biologists, acknowledged this unresolved problem in remarks following a lecture by J. S. Kennedy on the phase polyphenisms of migratory locusts (Kennedy, 1961). Dobzhansky referred to the “challenge to a geneticist” of explaining the adaptive switch between the sedentary and the migratory phenotypes of the locusts, which had been shown to be largely independent of genotype. He suggested that an extrachromosomal factor may be involved, a symbiotic microorganism that acts as a “plasmagene” whose multiplication would eventually stimulate phase change. Although Dobzhansky’s proposal was no more preposterous than some of the regulatory devices that have actually been discovered, Kennedy (1961) minced no words in his reply to this suggestion: . . . [W]e need not feel obliged to invoke a second organism to explain [phase polymorphism] unless we are reluctant to concede an important part to the environment as well as to heredity in moulding development. . . .

scholarly journals Phylogenetic Comparative Methods and the Evolution of Multivariate Phenotypes

2019 ◽  
Vol 50 (1) ◽  
pp. 405-425 ◽  
Author(s):  
Dean C. Adams ◽  
Michael L. Collyer
Keyword(s):  
Phylogenetic Analysis ◽  
Evolutionary Biology ◽  
Generalized Least Squares ◽  
Comparative Methods ◽  
High Dimensional ◽  
Phenotypic Integration ◽  
Phylogenetic Comparative Methods ◽  
Evolutionary Trends ◽  
Phenotype Space ◽  
Multivariate Phenotypes

Evolutionary biology is multivariate, and advances in phylogenetic comparative methods for multivariate phenotypes have surged to accommodate this fact. Evolutionary trends in multivariate phenotypes are derived from distances and directions between species in a multivariate phenotype space. For these patterns to be interpretable, phenotypes should be characterized by traits in commensurate units and scale. Visualizing such trends, as is achieved with phylomorphospaces, should continue to play a prominent role in macroevolutionary analyses. Evaluating phylogenetic generalized least squares (PGLS) models (e.g., phylogenetic analysis of variance and regression) is valuable, but using parametric procedures is limited to only a few phenotypic variables. In contrast, nonparametric, permutation-based PGLS methods provide a flexible alternative and are thus preferred for high-dimensional multivariate phenotypes. Permutation-based methods for evaluating covariation within multivariate phenotypes are also well established and can test evolutionary trends in phenotypic integration. However, comparing evolutionary rates and modes in multivariate phenotypes remains an important area of future development.

Heterochrony, dental ontogenetic diversity, and the circumvention of constraints in marsupial mammals and extinct relatives

Paleobiology ◽  
10.1666/13034 ◽  
2014 ◽  
Vol 40 (2) ◽  
pp. 222-237 ◽  
Author(s):  
Analía M. Forasiepi ◽  
Marcelo R. Sánchez-Villagra
Keyword(s):  
South America ◽  
Deciduous Tooth ◽  
Deciduous Teeth ◽  
Evolutionary Mechanisms ◽  
Morphological Disparity ◽  
Morphological Diversification ◽  
Long Period ◽  
Dental Eruption ◽  
Replacement Pattern ◽  
Ontogenetic Diversity

In marsupial mammals and their extinct relatives—collectively, metatherians—only the last premolar is replaced, but the timing of dental eruption is variable within the group. Our knowledge of fossils metatherians is limited, but is critical to understanding several aspects of the evolution and morphological diversification of this clade. We analyzed the sequence of eruption of 76 specimens of metatherians, including Sparassodonta, an extinct clade of specialized carnivores from South America. In Sparassodonta (1) the P3/p3 erupt simultaneously, in common with some didelphids (in other didelphids, p3 erupts before P3, whereas in the remaining didelphids, some peramelids, one caenolestid, andPucadelphysthis order is reversed); (2) the upper and lower molars at the same locus erupt more in synchrony than in other carnivorous metatherians in which the lower molars clearly precede the upper equivalents; (3) the upper canine in thylacosmilids and proborhyaenids is hypselodont; (4) species with similar molar morphologies have different morphologies of the deciduous premolars, suggesting diverse diets among the juveniles of different taxa; (5) deciduous teeth are functional for a long period of time, with thylacosmilids even retaining a functional DP3 in the permanent dentition. The retention of the DP3 and the hypertrophied and hypselodont upper canine of thylacosmilids represent clear heterochronic shifts. Specializations in the timing of dental eruption and in the deciduous tooth shape of sparassodonts are evolutionary mechanisms that circumvent constraints imposed by the metatherian replacement pattern and increase morphological disparity during ontogeny.

Measuring natural selection on multivariate phenotypic traits: a protocol for verifiable and reproducible analyses of natural selection

2019 ◽  
Vol 65 (3-4) ◽  
pp. 130-136 ◽  
Author(s):  
Facundo Xavier Palacio ◽  
Mariano Ordano ◽  
Santiago Benitez-Vieyra
Keyword(s):  
Regression Analysis ◽  
Natural Selection ◽  
Evolutionary Biology ◽  
Specific Model ◽  
Quadratic Model ◽  
Standard Errors ◽  
Phenotypic Traits ◽  
Linear Gradient ◽  
Selection Gradients ◽  
Model Residuals

The use of multiple regression analysis to quantify the regime and strength of natural selection in nature has been an influential approach in evolutionary biology over the last 36 years. However, many studies fail to report the protocol of estimation of selection coefficients (selection gradients) and the specific model assumptions, thus failing to verify and reproduce the estimation of selection coefficients. We present a brief overview of the Lande and Arnold’s approach and a step-by-step R routine to aid researchers to perform a verifiable and reproducible regression analysis of natural selection. The steps involved in the analysis include: (1) assessing collinearity between phenotypic traits, (2) testing normality of model residuals, and (3) testing multivariate normality of phenotypic traits. We also performed a series of simulations to test the effect of non-symmetrical (skewed) phenotypic traits on the estimation of linear selection gradients. These showed that the bias in the linear gradient increased with increased skewness in phenotypic traits for the quadratic model, whereas the linear gradient of a model with only linear terms was nearly independent of trait skewness. If none of the above assumptions are met, selection gradients need to be estimated from two separate equations, whereas standard errors must be computed using other methods (e.g. bootstrapping). We expect that the procedure outlined here and the availability of analytical codes motivate the verifiability and reproducibility of the Lande and Arnold’s approach in the study of microevolution.

scholarly journals Identification of an ant queen pheromone regulating worker sterility

2010 ◽  
Vol 277 (1701) ◽  
pp. 3793-3800 ◽  
Author(s):  
Luke Holman ◽  
Charlotte G. Jørgensen ◽  
John Nielsen ◽  
Patrizia d'Ettorre
Keyword(s):  
Evolutionary Biology ◽  
Cuticular Hydrocarbon ◽  
Division Of Labour ◽  
Queen Pheromone ◽  
Lasius Niger ◽  
Strong Response ◽  
Selective Forces ◽  
The Right ◽  
Worker Sterility ◽  
Reproductive Division

The selective forces that shape and maintain eusocial societies are an enduring puzzle in evolutionary biology. Ordinarily sterile workers can usually reproduce given the right conditions, so the factors regulating reproductive division of labour may provide insight into why eusociality has persisted over evolutionary time. Queen-produced pheromones that affect worker reproduction have been implicated in diverse taxa, including ants, termites, wasps and possibly mole rats, but to date have only been definitively identified in the honeybee. Using the black garden ant Lasius niger , we isolate the first sterility-regulating ant queen pheromone. The pheromone is a cuticular hydrocarbon that comprises the majority of the chemical profile of queens and their eggs, and also affects worker behaviour, by reducing aggression towards objects bearing the pheromone. We further show that the pheromone elicits a strong response in worker antennae and that its production by queens is selectively reduced following an immune challenge. These results suggest that the pheromone has a central role in colony organization and support the hypothesis that worker sterility represents altruistic self-restraint in response to an honest quality signal.

scholarly journals Rapid action in the Palaeogene, the relationship between phenotypic and taxonomic diversification in Coenozoic mammals

2013 ◽  
Vol 280 (1750) ◽  
pp. 20122244 ◽  
Author(s):  
P. Raia ◽  
F. Carotenuto ◽  
F. Passaro ◽  
P. Piras ◽  
D. Fulgione ◽  
...  
Keyword(s):  
Body Size ◽  
Resource Utilization ◽  
Evolutionary Biology ◽  
Species Level ◽  
Phenotypic Evolution ◽  
Diversification Rates ◽  
Rapid Action ◽  
Hierarchic Level ◽  
The Relationship ◽  
Size Estimates

A classic question in evolutionary biology concerns the tempo and mode of lineage evolution. Considered variously in relation to resource utilization, intrinsic constraints or hierarchic level, the question of how evolutionary change occurs in general has continued to draw the attention of the field for over a century and a half. Here we use the largest species-level phylogeny of Coenozoic fossil mammals (1031 species) ever assembled and their body size estimates, to show that body size and taxonomic diversification rates declined from the origin of placentals towards the present, and very probably correlate to each other. These findings suggest that morphological and taxic diversifications of mammals occurred hierarchically, with major shifts in body size coinciding with the birth of large clades, followed by taxonomic diversification within these newly formed clades. As the clades expanded, rates of taxonomic diversification proceeded independently of phenotypic evolution. Such a dynamic is consistent with the idea, central to the Modern Synthesis, that mammals radiated adaptively, with the filling of adaptive zones following the radiation.

scholarly journals Genome-wide patterns of divergence during speciation: the lake whitefish case study

2012 ◽  
Vol 367 (1587) ◽  
pp. 354-363 ◽  
Author(s):  
S. Renaut ◽  
N. Maillet ◽  
E. Normandeau ◽  
C. Sauvage ◽  
N. Derome ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Genomic Islands ◽  
Next Generation Sequencing Data ◽  
Adaptive Divergence ◽  
Phenotypic Traits ◽  
Lake Whitefish ◽  
Sequencing Data ◽  
Species Pairs ◽  
Selective Forces ◽  
Genomic Regions

The nature, size and distribution of the genomic regions underlying divergence and promoting reproductive isolation remain largely unknown. Here, we summarize ongoing efforts using young (12 000 yr BP) species pairs of lake whitefish ( Coregonus clupeaformis ) to expand our understanding of the initial genomic patterns of divergence observed during speciation. Our results confirmed the predictions that: (i) on average, phenotypic quantitative trait loci (pQTL) show higher F ST values and are more likely to be outliers (and therefore candidates for being targets of divergent selection) than non-pQTL markers; (ii) large islands of divergence rather than small independent regions under selection characterize the early stages of adaptive divergence of lake whitefish; and (iii) there is a general trend towards an increase in terms of numbers and size of genomic regions of divergence from the least (East L.) to the most differentiated species pair (Cliff L.). This is consistent with previous estimates of reproductive isolation between these species pairs being driven by the same selective forces responsible for environment specialization. Altogether, dwarf and normal whitefish species pairs represent a continuum of both morphological and genomic differentiation contributing to ecological speciation. Admittedly, much progress is still required to more finely map and circumscribe genomic islands of speciation. This will be achieved through the use of next generation sequencing data but also through a better quantification of phenotypic traits moulded by selection as organisms adapt to new environmental conditions.

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