scholarly journals The evolution of non-reproductive workers in insect colonies with haplodiploid genetics

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Jason W Olejarz ◽  
Benjamin Allen ◽  
Carl Veller ◽  
Martin A Nowak
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Functional Relationship ◽  
Genetic Relatedness ◽  
Reproductive Potential ◽  
Reproductive Rate ◽  
Distinct Form ◽  
Biological Organization ◽  
Selective Forces ◽  
Widespread Belief

Eusociality is a distinct form of biological organization. A key characteristic of advanced eusociality is the presence of non-reproductive workers. Why evolution should produce organisms that sacrifice their own reproductive potential in order to aid others is an important question in evolutionary biology. Here, we provide a detailed analysis of the selective forces that determine the emergence and stability of non-reproductive workers. We study the effects, in situations where the queen of the colony has mated once or several times, of recessive and dominant sterility alleles acting in her offspring. Contrary to widespread belief based on heuristic arguments of genetic relatedness, non-reproductive workers can easily evolve in polyandrous species. The crucial quantity is the functional relationship between a colony’s reproductive rate and the fraction of non-reproductive workers present in that colony. We derive precise conditions for natural selection to favor the evolution of non-reproductive workers.

scholarly journals Genome size correlates with reproductive fitness in seed beetles

2015 ◽  
Vol 282 (1815) ◽  
pp. 20151421 ◽  
Author(s):  
Göran Arnqvist ◽  
Ahmed Sayadi ◽  
Elina Immonen ◽  
Cosima Hotzy ◽  
Daniel Rankin ◽  
...  
Keyword(s):  
Life History ◽  
Natural Selection ◽  
Genome Size ◽  
Evolutionary Biology ◽  
Large Scale ◽  
Life History Traits ◽  
Single Species ◽  
Reproductive Fitness ◽  
Correlated Evolution ◽  
Seed Beetles

The ultimate cause of genome size (GS) evolution in eukaryotes remains a major and unresolved puzzle in evolutionary biology. Large-scale comparative studies have failed to find consistent correlations between GS and organismal properties, resulting in the ‘ C -value paradox’. Current hypotheses for the evolution of GS are based either on the balance between mutational events and drift or on natural selection acting upon standing genetic variation in GS. It is, however, currently very difficult to evaluate the role of selection because within-species studies that relate variation in life-history traits to variation in GS are very rare. Here, we report phylogenetic comparative analyses of GS evolution in seed beetles at two distinct taxonomic scales, which combines replicated estimation of GS with experimental assays of life-history traits and reproductive fitness. GS showed rapid and bidirectional evolution across species, but did not show correlated evolution with any of several indices of the relative importance of genetic drift. Within a single species, GS varied by 4–5% across populations and showed positive correlated evolution with independent estimates of male and female reproductive fitness. Collectively, the phylogenetic pattern of GS diversification across and within species in conjunction with the pattern of correlated evolution between GS and fitness provide novel support for the tenet that natural selection plays a key role in shaping GS evolution.

scholarly journals Evolutionary biology today and the call for an extended synthesis

2017 ◽  
Vol 7 (5) ◽  
pp. 20160145 ◽  
Author(s):  
Douglas J. Futuyma
Keyword(s):  
Natural Selection ◽  
Evolutionary Theory ◽  
Evolutionary Biology ◽  
Epigenetic Inheritance ◽  
Reaction Norm ◽  
Evolutionary Synthesis ◽  
Historical Background ◽  
Extended Evolutionary Synthesis ◽  
Extended Synthesis ◽  
Proximate Causation

Evolutionary theory has been extended almost continually since the evolutionary synthesis (ES), but except for the much greater importance afforded genetic drift, the principal tenets of the ES have been strongly supported. Adaptations are attributable to the sorting of genetic variation by natural selection, which remains the only known cause of increase in fitness. Mutations are not adaptively directed, but as principal authors of the ES recognized, the material (structural) bases of biochemistry and development affect the variety of phenotypic variations that arise by mutation and recombination. Against this historical background, I analyse major propositions in the movement for an ‘extended evolutionary synthesis’. ‘Niche construction' is a new label for a wide variety of well-known phenomena, many of which have been extensively studied, but (as with every topic in evolutionary biology) some aspects may have been understudied. There is no reason to consider it a neglected ‘process’ of evolution. The proposition that phenotypic plasticity may engender new adaptive phenotypes that are later genetically assimilated or accommodated is theoretically plausible; it may be most likely when the new phenotype is not truly novel, but is instead a slight extension of a reaction norm already shaped by natural selection in similar environments. However, evolution in new environments often compensates for maladaptive plastic phenotypic responses. The union of population genetic theory with mechanistic understanding of developmental processes enables more complete understanding by joining ultimate and proximate causation; but the latter does not replace or invalidate the former. Newly discovered molecular phenomena have been easily accommodated in the past by elaborating orthodox evolutionary theory, and it appears that the same holds today for phenomena such as epigenetic inheritance. In several of these areas, empirical evidence is needed to evaluate enthusiastic speculation. Evolutionary theory will continue to be extended, but there is no sign that it requires emendation.

Evolutionary Design of Intestinal Nutrient Absorption: Enough but Not Too Much

Physiology ◽  
1991 ◽  
Vol 6 (2) ◽  
pp. 92-96 ◽  
Author(s):  
Jared Diamond
Keyword(s):  
Small Intestine ◽  
Absorptive Capacity ◽  
Nutrient Intake ◽  
Evolutionary Biology ◽  
Nutrient Absorption ◽  
Evolutionary Design ◽  
Widespread Belief ◽  
Physiological Systems

Contrary to previous widespread belief, the small intestine possesses only a modest excess of nutrient absorptive capacity over nutrient intake. This problem exemplifies a field that is now emerging at the infrace between physiology and evolutionary biology and that is concerned with the relation between evolved capacities and natural loads of physiological systems.

Evolutionary morphology: beyond the analogous, the anecdotal, and the ad hoc

Paleobiology ◽  
1985 ◽  
Vol 11 (1) ◽  
pp. 120-138 ◽  
Author(s):  
Daniel C. Fisher
Keyword(s):  
Natural Selection ◽  
Ad Hoc ◽  
Reproductive Potential ◽  
Context Dependency ◽  
Evolutionary Morphology ◽  
Structured Design ◽  
Behavioral System ◽  
Essential Components ◽  
History Of

Many questions have emerged recently regarding the importance and methodology of analysis of adaptation. Divergent views reflect both problems of definition and more substantive issues of interpretation. Defining the state of adaptation in terms of its contribution to current fitness, rather than origin by natural selection, is essential if natural selection is to be considered anexplanationof adaptation. The context dependency and relativity of fitness apply also to adaptation. Design criteria are essential components of adaptation, but only to the extent that they are subsumed as elements of the causal interactions determining relative reproductive potential. The local, relational, contingent character of adaptation supports only limited reference to improvement. Most long-term patterns of change can be better described as diffusion within a structured design-space than as progressive improvement of design. The analysis of adaptation is part of a broader inquiry into the processes and constraints that control form and the history of changing form. It offers one perspective on how organisms operate on ecological time scales and how their configurations might be maintained or transformed over evolutionary time. Hypotheses concerning adaptation are sometimes tested by reference to predictions concerning the central tendency or trend of some aspect of an anatomical-behavioral system. These can be interpreted with minimal reference to assumptions of optimality if the analysis is viewed in terms of Bayesian inference. However, an alternative and frequently preferable approach to testing relies on limit-oriented predictions. Analysis of adaptation can be visualized as inferring the pattern and nature of interactions comprising the causal plexus that determines fitness. A comprehensive understanding of form and form-change requires that this be integrated with the perspective offered by studies of development, genetics, phylogenetic history, and external perturbations acting on the system.

scholarly journals The evolution of superstitious and superstition-like behaviour

2008 ◽  
Vol 276 (1654) ◽  
pp. 31-37 ◽  
Author(s):  
Kevin R Foster ◽  
Hanna Kokko
Keyword(s):  
Popular Culture ◽  
Natural Selection ◽  
Simple Model ◽  
Correct Response ◽  
Evolutionary Biology ◽  
Adaptive Behaviour ◽  
Multiple Events ◽  
Cause And Effect ◽  
Pascal’S Wager ◽  
Hamilton's Rule

Superstitious behaviours, which arise through the incorrect assignment of cause and effect, receive considerable attention in psychology and popular culture. Perhaps owing to their seeming irrationality, however, they receive little attention in evolutionary biology. Here we develop a simple model to define the condition under which natural selection will favour assigning causality between two events. This leads to an intuitive inequality—akin to an amalgam of Hamilton's rule and Pascal's wager—-that shows that natural selection can favour strategies that lead to frequent errors in assessment as long as the occasional correct response carries a large fitness benefit. It follows that incorrect responses are the most common when the probability that two events are really associated is low to moderate: very strong associations are rarely incorrect, while natural selection will rarely favour making very weak associations. Extending the model to include multiple events identifies conditions under which natural selection can favour associating events that are never causally related. Specifically, limitations on assigning causal probabilities to pairs of events can favour strategies that lump non-causal associations with causal ones. We conclude that behaviours which are, or appear, superstitious are an inevitable feature of adaptive behaviour in all organisms, including ourselves.

scholarly journals Evolution of correlated complexity in the radically different courtship signals of birds-of-paradise

2018 ◽  
Author(s):  
Russell A. Ligon ◽  
Christopher D. Diaz ◽  
Janelle L. Morano ◽  
Jolyon Troscianko ◽  
Martin Stevens ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Evolutionary Biology ◽  
Evolutionary Dynamics ◽  
Functional Integration ◽  
Empirical Support ◽  
Evolutionary Patterns ◽  
Evolutionary Innovation ◽  
Birds Of Paradise ◽  
Analytical Approaches

Ornaments used in courtship often vary wildly among species, reflecting the evolutionary interplay between mate preference functions and the constraints imposed by natural selection. Consequently, understanding the evolutionary dynamics responsible for ornament diversification has been a longstanding challenge in evolutionary biology. However, comparing radically different ornaments across species, as well as different classes of ornaments within species, is a profound challenge to understanding diversification of sexual signals. Using novel methods and a unique natural history dataset, we explore evolutionary patterns of ornament evolution in a group - the birds-of-paradise - exhibiting dramatic phenotypic diversification widely assumed to be driven by sexual selection. Rather than the tradeoff between ornament types originally envisioned by Darwin and Wallace, we found positive correlations among cross-modal (visual/acoustic) signals indicating functional integration of ornamental traits into a composite unit - the courtship phenotype. Furthermore, given the broad theoretical and empirical support for the idea that systemic robustness - functional overlap and interdependency - promotes evolutionary innovation, we posit that birds-of-paradise have radiated extensively through ornamental phenotype space as a consequence of the robustness in the courtship phenotype that we document at a phylogenetic scale. We suggest that the degree of robustness in courtship phenotypes among taxa can provide new insights into the relative influence of sexual and natural selection on phenotypic radiations.Author SummaryAnimals frequently vary widely in ornamentation, even among closely related species. Understanding the patterns that underlie this variation is a significant challenge, requiring comparisons among drastically different traits - like comparing apples to oranges. Here, we use novel analytical approaches to quantify variation in ornamental diversity and richness across the wildly divergent birds-of-paradise, a textbook example of how sexual selection can profoundly shape organismal phenotypes. We find that color and acoustic complexity, along with behavior and acoustic complexity, are positively correlated across evolutionary time-scales. Positive covariation among ornament classes suggests that selection is acting on correlated suites of traits - a composite courtship phenotype - and that this integration may be partially responsible for the extreme variation we see in birds-of-paradise.

scholarly journals Natural Selection at an Exceptionally Long GGC Repeat in the Human RASGEF1C and Divergent Genotypes in Late-onset Neurocognitive Disorder

2021 ◽  
Author(s):  
Z Jafarian ◽  
S Khamse ◽  
H Afshar ◽  
Khorram Khorshid HR ◽  
A Delbari ◽  
...  
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Late Onset ◽  
Core Promoter ◽  
Human Subjects ◽  
Specific Gene ◽  
Protein Coding ◽  
Repeat Allele ◽  
Complex Disorders ◽  
Selection For

Abstract Across the human protein-coding genes, the neuron-specific gene, RASGEF1C, contains the longest (GGC)-repeat, spanning its core promoter and 5′ untranslated region (RASGEF1C-201 ENST00000361132.9). RASGEF1C expression dysregulation occurs in late-onset neurocognitive disorders (NCDs), such as Alzheimer’s disease. Here we sequenced the GGC-repeat in a sample of human subjects (N = 269), consisting of late-onset NCDs (N = 115) and controls (N = 154). We also studied the status of this STR across vertebrates. The 6-repeat allele of this repeat was the predominant allele in the controls (frequency = 0.85) and NCD patients (frequency = 0.78). The NCD genotype compartment consisted of an excess of genotypes that lacked the 6-repeat (Mid-P exact = 0.004). We also detected divergent genotypes that were present in five NCD patients and not in the controls (Mid-P exact = 0.007). This STR expanded beyond 2-repeats specifically in primates, and was at maximum length in human. We conclude that there is natural selection for the 6-repeat allele of the RASGEF1C (GGC)-repeat in human, and significant divergence from that allele in late-onset NCDs. Indication of natural selection for predominantly abundant STR alleles and divergent genotypes enhance the perspective of evolutionary biology and disease pathogenesis in human complex disorders.

scholarly journals The Evolution of Mass Cell Suicide in Bacterial Warfare

2020 ◽  
Author(s):  
Elisa T. Granato ◽  
Kevin R. Foster
Keyword(s):  
Escherichia Coli ◽  
Natural Selection ◽  
Reproductive Potential ◽  
Time Lapse ◽  
List Type ◽  
E Coli ◽  
Toxin Exposure ◽  
Small Benefit ◽  
Will Self ◽  
Cell Suicide

SUMMARYBehaviours that reliably cause the death of an actor are typically strongly disfavoured by natural selection, and yet many bacteria undergo cell lysis to release anti-competitor toxins [1–4]. This behaviour is most easily explained if only a few cells die to release toxins and help their clonemates, but the number of cells that actually lyse during bacterial warfare is unknown. The challenge is that one cannot distinguish cells that have undergone programmed suicide from those that were simply killed by a competitor’s toxin. We developed a two-colour fluorescence reporter assay in Escherichia coli to overcome this problem. Surprisingly, this revealed conditions where nearly all cells undergo programmed lysis. Adding a DNA-damaging toxin (DNase colicin) to a focal strain causes it to engage in mass cell suicide where around 85% of cells lyse to release their own toxin. Time-lapse 3D confocal microscopy revealed that self-lysis occurs at even higher frequencies (~94%) at the interface between competing colonies. We sought to understand how such high levels of cell suicide could be favoured by natural selection. Exposing E. coli that do not perform lysis to the DNase colicin revealed that mass lysis only occurs when cells are going to die anyway from toxin exposure. From an evolutionary perspective, this renders the behaviour cost-free as these cells have zero reproductive potential. This explains how mass cell suicide can evolve, as any small benefit to surviving clonemates can lead to the strategy being favoured by natural selection. Our findings have strong parallels to the suicidal attacks of social insects [5–8], which are also performed by individuals with low reproductive potential, suggesting convergent evolution in these very different organisms.HIGHLIGHTSA novel assay can detect Escherichia coli undergoing cell suicide to release toxinsWe quantified the frequency of suicidal self-lysis during competitionsUnder some conditions, nearly all cells will self-lyse to release toxinsSelf-lysis makes evolutionary sense as cells will die anyway from competitors’ toxins

The naked ape as an evolutionary model, 50 years later

2018 ◽  
Vol 68 (3) ◽  
pp. 227-246
Author(s):  
Nico M. van Straalen
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Evolutionary Model ◽  
Developmental Constraints ◽  
Body Hair ◽  
Product Evolution ◽  
Adaptive Explanation ◽  
History Of ◽  
Popular Texts ◽  
The Brain

AbstractEvolution acts through a combination of four different drivers: (1) mutation, (2) selection, (3) genetic drift, and (4) developmental constraints. There is a tendency among some biologists to frame evolution as the sole result of natural selection, and this tendency is reinforced by many popular texts. “The Naked Ape” by Desmond Morris, published 50 years ago, is no exception. In this paper I argue that evolutionary biology is much richer than natural selection alone. I illustrate this by reconstructing the evolutionary history of five different organs of the human body: foot, pelvis, scrotum, hand and brain. Factors like developmental tinkering, by-product evolution, exaptation and heterochrony are powerful forces for body-plan innovations and the appearance of such innovations in human ancestors does not always require an adaptive explanation. While Morris explained the lack of body hair in the human species by sexual selection, I argue that molecular tinkering of regulatory genes expressed in the brain, followed by positive selection for neotenic features, may have been the driving factor, with loss of body hair as a secondary consequence.

scholarly journals Fluctuating selection: the perpetual renewal of adaptation in variable environments

2010 ◽  
Vol 365 (1537) ◽  
pp. 87-97 ◽  
Author(s):  
Graham Bell
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Natural Populations ◽  
Phenotypic Variance ◽  
Weak Selection ◽  
Fluctuating Selection ◽  
Environmental Variance ◽  
Strong Selection ◽  
Genomic Studies ◽  
Over Time

Darwin insisted that evolutionary change occurs very slowly over long periods of time, and this gradualist view was accepted by his supporters and incorporated into the infinitesimal model of quantitative genetics developed by R. A. Fisher and others. It dominated the first century of evolutionary biology, but has been challenged in more recent years both by field surveys demonstrating strong selection in natural populations and by quantitative trait loci and genomic studies, indicating that adaptation is often attributable to mutations in a few genes. The prevalence of strong selection seems inconsistent, however, with the high heritability often observed in natural populations, and with the claim that the amount of morphological change in contemporary and fossil lineages is independent of elapsed time. I argue that these discrepancies are resolved by realistic accounts of environmental and evolutionary changes. First, the physical and biotic environment varies on all time-scales, leading to an indefinite increase in environmental variance over time. Secondly, the intensity and direction of natural selection are also likely to fluctuate over time, leading to an indefinite increase in phenotypic variance in any given evolving lineage. Finally, detailed long-term studies of selection in natural populations demonstrate that selection often changes in direction. I conclude that the traditional gradualist scheme of weak selection acting on polygenic variation should be supplemented by the view that adaptation is often based on oligogenic variation exposed to commonplace, strong, fluctuating natural selection.

Sign in / Sign up

Export Citation Format

Share Document