Evolutionary basis of sexual adaptation.
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Biological Evolution↗
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Results for “Evolutionary adaptability”
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Evolutionary implications of the adaptation to different immune systems in a parasite with a complex life cycle.
Many diseases are caused by parasites with complex life cycles that involve several hosts. If parasites cope better with only one of the different types of immune systems of their host species, we might expect a trade-off in parasite performance in the different hosts, that likely influences the evolution of virulence. We tested this hypothesis in a naturally co-evolving host-parasite system consisting of the tapeworm Schistocephalus solidus and its intermediate hosts, a copepod, Macrocyclops albidus, and the three-spined stickleback Gasterosteus aculeatus. We did not find a trade-off between infection success in the two hosts. Rather, tapeworms seem to trade-off adaptation towards different parts of their hosts' immune systems. Worm sibships that performed better in the invertebrate host also seem to be able to evade detection by the fish innate defence systems, i.e. induce lower levels of activation of innate immune components. These worm variants were less harmful for the fish host likely due to reduced costs of an activated innate immune system. These findings substantiate the impact of both hosts' immune systems on parasite performance and virulence.
Adaptation, Physiological↗
Functional evolutionary genetics and plant adaptation: linking phenotype and genotype.
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Adaptation, Physiological↗
Testing evolutionary hypotheses about human biological adaptation using cross-cultural comparison.
Physiological data from a range of human populations living in different environments can provide valuable information for testing evolutionary hypotheses about human adaptation. By taking into account the effects of population history, phylogenetic comparative methods can help us determine whether variation results from selection due to particular environmental variables. These selective forces could even be due to cultural traits-which means that gene-culture co-evolution may be occurring. In this paper, we outline two examples of the use of these approaches to test adaptive hypotheses that explain global variation in two physiological traits: the first is lactose digestion capacity in adults, and the second is population sex-ratio at birth. We show that lower than average sex ratio at birth is associated with high fertility, and argue that global variation in sex ratio at birth has evolved as a response to the high physiological costs of producing boys in high fertility populations.
Adaptation, Physiological↗
Design of graph-based evolutionary algorithms: a case study for chemical process networks.
This paper describes the adaptation of evolutionary algorithms (EAs) to the structural optimization of chemical engineering plants, using rigorous process simulation combined with realistic costing procedures to calculate target function values. To represent chemical engineering plants, a network representation with typed vertices and variable structure will be introduced. For this representation, we introduce a technique on how to create problem specific search operators and apply them in stochastic optimization procedures. The applicability of the approach is demonstrated by a reference example. The design of the algorithms will be oriented at the systematic framework of metric-based evolutionary algorithms (MBEAs). MBEAs are a special class of evolutionary algorithms, fulfilling certain guidelines for the design of search operators, whose benefits have been proven in theory and practice. MBEAs rely upon a suitable definition of a metric on the search space. The definition of a metric for the graph representation will be one of the main issues discussed in this paper. Although this article deals with the problem domain of chemical plant optimization, the algorithmic design can be easily transferred to similar network optimization problems. A useful distance measure for variable dimensionality search spaces is suggested.
Algorithms↗
The adaptive dynamics of function-valued traits.
This study extends the framework of adaptive dynamics to function-valued traits. Such adaptive traits naturally arise in a great variety of settings: variable or heterogeneous environments, age-structured populations, phenotypic plasticity, patterns of growth and form, resource gradients, and in many other areas of evolutionary ecology. Adaptive dynamics theory allows analysing the long-term evolution of such traits under the density-dependent and frequency-dependent selection pressures resulting from feedback between evolving populations and their ecological environment. Starting from individual-based considerations, we derive equations describing the expected dynamics of a function-valued trait in asexually reproducing populations under mutation-limited evolution, thus generalizing the canonical equation of adaptive dynamics to function-valued traits. We explain in detail how to account for various kinds of evolutionary constraints on the adaptive dynamics of function-valued traits. To illustrate the utility of our approach, we present applications to two specific examples that address, respectively, the evolution of metabolic investment strategies along resource gradients, and the evolution of seasonal flowering schedules in temporally varying environments.
Adaptation, Biological↗
Evolutionary traction: the cost of adaptation and the evolution of sex.
The advantage of sexual reproduction remains a puzzle for evolutionary biologists. Everything else being equal, asexual populations are expected to have twice the number of offspring produced by similar sexual populations. Yet, asexual species are uncommon among higher eukaryotes. In models assuming small populations, high mutation rates, or frequent environmental changes, sexual reproduction seems to have at least a two-fold advantage over asexuality. But the advantage of sex for large populations, low mutation rates, and rare or mild environmental changes remains a conundrum. Here we show that without recombination, rare advantageous mutations can result in increased accumulation of deleterious mutations ('evolutionary traction'), which explains the long-term advantage of sex under a wide parameter range.
Adaptation, Biological↗
Adaptive dynamics, game theory and evolutionary population genetics.
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Adaptation, Biological↗
Tandem duplication-driven expansion and UV-B stress adaptation of the LHC gene family in Artemisia annua L.
BACKGROUND: Artemisia annua L., is the primary natural source of the antimalarial drug artemisinin. In nature, fluctuating light is a major environmental stress that affects plant growth and artemisinin biosynthesis. Although the light-harvesting chlorophyll a/b-binding (LHC) superfamily plays a key role in mediating plant responses to fluctuating light, systematic research of this gene family in A. annua has not yet been conducted, limiting our understanding of light adaptation in this medicinally important species. RESULTS: This study investigated the evolutionary dynamics and functional adaptation of the light-harvesting chlorophyll a/b-binding (LHC) superfamily in A. annua, with a focus on the early light‑induced protein (ELIP) subfamily. Comparative genomics of 24 plant species showed that the LHC superfamily recently expanded in the examined Asteraceae lineages through duplication events. In A. annua, 229 LHC genes identified from four haplotype genomes comprised 205 allelic and 24 haplotype-specific loci, with the ELIP subfamily expanding significantly via tandem duplication. Notably, compared to non-Asteraceae plants, ELIPs exhibited a uniform single-exon architecture, indicating it is a genomic feature unique to Asteraceae plants. Population genomics of 41 individuals showed dynamic copy number variations ranging from 1 to 4 copies per locus. Interestingly, a structurally disrupted ELIP allele remained transcriptionally active and produced long aberrant transcripts, showing that this subfamily is still actively evolving. Under UV-B stress, AaELIP loci showed synchronized induction trend but differed in expression levels, suggesting a division into major and auxiliary roles within the expanded tandem cluster. Overall, while the response of ELIPs to light stress is evolutionarily conserved, this dramatic expansion and structural streamlining of AaELIPs may represent a key evolutionary adaptation that enhances the plant's ability to cope with intense light and radiation stress. CONCLUSIONS: Collectively, this study demonstrates a significant expansion of the LHC superfamily in A. annua, especially within the ELIP subfamily, as well as its robust response to UV-B treatment, underscoring the essential role of ELIPs in mediating light stress responses. These findings provide a valuable foundation for future research to uncover the molecular mechanisms underlying A. annua's adaptation to complex light environments.
Artemisia annua↗
Comparative analysis of olfactory receptor repertoires reveals evolutionary dynamics and high-altitude adaptation in Schizopygopsis younghusbandi based on the chromosome-level genomes.
The olfactory receptor (OR) gene represent a significant multigene family in vertebrates, forming the core molecular basis of olfactory perception and playing a crucial role in the environmental adaptation of species. High-altitude ecosystems represent extreme habitats characterized by specific abiotic stresses, including low oxygen levels, low temperatures, and intense ultraviolet radiation. These environments also exhibit low aquatic biodiversity and a limited variety of odor molecules, factors that have influenced the adaptive evolution of the sensory systems in endemic species. However, the genetic mechanisms underlying olfactory adaptation in high-altitude freshwater fish remained inadequately understood. In this study, we performed comparative genomics analyses to reveal the evolutionary processes underlying the adaptive and functional evolution of OR genes in S. younghusbandi, a cyprinid fish endemic to the Qinghai-Xizang Plateau. The results indicated that, compared to their low-altitude relatives, S. younghusbandi possessed a significantly smaller number of OR genes, with only 98 genes, which revealed the contraction of the gene family. Phylogenetic analysis revealed that the OR genes of cyprinid fish could be categorized into two major lineages: type I and type II. The η and δ families, which perceive water-soluble odors, in S. younghusbandi underwent significant and specific expansion, while the ε family was completely absent. This pattern reflected adaptive changes in olfactory recognition to accommodate the simplified odor spectrum of high-altitude water bodies. Chromosomal localization analysis demonstrated that OR genes were clustered, and collinearity analysis confirmed the presence of conserved genomic fragments among species. Selection pressure analysis revealed that the Ka/Ks values of all homologous gene pairs were less than 1, indicating that the OR genes of S. younghusbandi underwent strong purifying selection as a group to preserve core olfactory function. A few genes exhibited relaxed selection characteristics, which may have facilitated the fine-tuning of adaptability to high-altitude environments. In conclusion, this study elucidated the evolutionary dynamics and adaptive characteristics of the OR gene in S. younghusbandi, offering a new perspective on the molecular mechanisms underlying olfactory adaptation at high altitudes and enriching the research on sensory evolution in vertebrates.
Schizopygopsis younghusbandi↗
Evolutionary legacy of the "living fossil" genus Parrotia (Hamamelidaceae): genomic insights into species divergence and polygenic adaptation.
Despite their long evolutionary history, the genomic basis of adaptation and speciation in "living fossil" plants remain largely unexplored. Parrotia, a Tertiary relict tree genus with two extant species, P. subaequalis and P. persica, exhibits a disjunct distribution between East Asia and West Asia. Here, we present the first chromosome-level assemblies for both species, confirmed their sibling relationship, and dated the speciation event to the early Miocene. The recent proliferation of long-terminal repeat retrotransposons has driven the genome expansion in P. subaequalis. We detected widespread heterogeneous genomic differentiation between species. Extensive signals of divergent selection, local adaptation, and elevated Ka/Ks ratios in Parrotia indicate that this genus has undergone adaptive evolution in distinct refugia, challenging the notion of it as an "evolutionary dead end". Our findings provide new insights into the genomic evolution, environmental adaptation, and speciation of this "living fossil" tree genus.
Genome, Plant↗
An adaptive immune optimization algorithm for energy minimization problems.
Based on the immune theory of biology, a novel evolutionary algorithm, adaptive immune optimization algorithm (AIOA), is proposed. In AIOA, density regulation and immune selection is adopted to control the individual diversity and the convergence adaptively. By an application of the algorithm to the optimization of test functions, it is shown that the algorithm is a highly efficient optimization method compared with other stochastic optimization methods. The algorithm was also applied to the optimization of Lennard-Jones clusters, and the results show that the method can find the optimal structure of N</=80 with a very high efficiency. The proposed algorithm may be a good tool for fast global optimization in chemical or biological molecular simulations.
Journal Article↗
The adaptive role of maladaptive neurosis: an evolutionary misconception.
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Adaptation, Psychological↗
Fetal adaptation to stress: Part II. Evolutionary aspects; stress-induced hippocampal damage; long-term effects on behavior; consequences on adult health.
Humans share adaptative capacities to stress with other species, as demonstrated on amphibians: the physiological response to experimental water volume and food deprivation results in the activation of the endocrine axes that drive metamorphosis, in particular the neuroendocrine stress system. Unfavorable effects may, however, occur, probably due to inappropriate timing and/or duration of stress: recent experiments are converging to show a profound impairment of hippocampal functioning in the offspring of mothers exposed to prenatal stress. Moreover, fetal changes are likely one of the risk factors for a number of diseases in adulthood.
Adaptation, Physiological↗
Evolutionary changes in mutation rates and spectra and their influence on the adaptation of pathogens.
The evolutionary tuning of mutational processes may play a key role in prokaryotic evolution, particularly among pathogens. In this paper we review the evidence that genetic systems controlling the rate and spectrum of heritable mutations have evolved to optimize levels of adaptive variation and rates of genetic change.
Adaptation, Physiological↗
Body surface adaptations to boundary-layer dynamics.
Evolutionary processes have adapted nektonic animals to interact efficiently with the water that surrounds them. Not all these adaptations serve the same purpose. This paper concentrates on reduction of drag due to friction in the boundary layer close to the body surface. Mucus, compliant skins, scales, riblets and roughness may influence the flow velocity gradient, the type of flow and the thickness of the boundary layer around animals, and may seriously affect their drag in a positive or negative way. The long-chain polymers found in mucus decrease the pressure gradient and considerably reduced drag due to friction. The effect is probably due to channelling of the flow particles in the direction of the main flow, resulting in a reduction of turbulence. Compliant surfaces could probably reduce drag by equalising and distributing pressure pulses. However, the existing evidence that drag reduction actually occurs is not convincing. There is no indication that instantaneous heating, reducing the viscosity in the boundary layer, is used by animals as a drag-reducing technique. Small longitudinal ridges on rows of scales on fish can reduce shear stress in the boundary by a maximum of 10% compared with the shear stress of a smooth surface. The mechanism is based on the impedance of cross flow under well-defined conditions. The effect has been visualized with the use of particle image velocimetry techniques. The function of the swords and spears of several fast, pelagic, predatory fish species is still enigmatic. The surface structure of the sword of a swordfish is shown to be both rough and porous. The height of the roughness elements on the tip of the sword is close to the critical value for the induction of a laminar-to-turbulent flow transition at moderate cruising speeds. A flow tank is described that is designed to visualize the effects of surface imperfections on flow in the boundary layer in direct comparison with a smooth flat wall. The flow in a 1 m long, 10 cm high and 1 cm wide channel is visualized by illuminating the particles in a thin laser light sheet. The first results show that a rough surface increases the shear stress in the boundary layer and makes it thinner. The function of the roughness on the sword of a swordfish is probably to reduce the total drag by generating premature turbulence and by boundary layer thinning, despite an increased friction over the surface of the sword. The function of the porous surface structures on the sword, and of the porous skins of sharks and of the castor oil fish, will probably be discovered soon using new particle image velocimetry techniques applied under strong magnification to visualize the local behaviour of the flow.
Adaptation, Physiological↗
Interactions of citrate synthases from osmoconforming and osmoregulating animals with salt: possible signs of molecular eco-adaptation?
This study considers differential sensitivity of citrate synthase (citrate oxaloacetatelyase [CoA acetylating]) EC 4.1.3.7. from an osmoconforming animal (sea anemone) and an osmoregulating animal (the pig) to salt. Attention is drawn to the fact that the osmoconforming sea anemone is in essence a sessile creature while the pig is readily mobile and able to change its ionic environment at will. It had been shown earlier that citrate synthase from another osmoconformer (oyster) is also not sensitive to ionic strength while citrate synthase from osmoregulating white shrimp is sensitive to increasing levels of salt. However, these enzymes are characteristically regulated by ATP and alpha-ketoglutarate. Both forms of citrate synthase are denatured by 6 M guanidine hydrochloride and are aided by salt levels in their refolding but the rate and extent of refolding of the osmoconformer citrate synthase are greater than those of the osmoregulator citrate synthase. Catalytic activity of both forms of citrate synthase is inhibited by incubation in distilled water; osmoconformer citrate synthase was inhibited completely in 7 h while osmoregulator citrate synthase was inhibited only 60% in this time and 80% after 22 h in distilled water. The eco-adaptive and evolutionary implications of these findings are discussed.
Adaptation, Physiological↗
Protein and DNA sequence determinants of thermophilic adaptation.
There have been considerable attempts in the past to relate phenotypic trait--habitat temperature of organisms--to their genotypes, most importantly compositions of their genomes and proteomes. However, despite accumulation of anecdotal evidence, an exact and conclusive relationship between the former and the latter has been elusive. We present an exhaustive study of the relationship between amino acid composition of proteomes, nucleotide composition of DNA, and optimal growth temperature (OGT) of prokaryotes. Based on 204 complete proteomes of archaea and bacteria spanning the temperature range from -10 degrees C to 110 degrees C, we performed an exhaustive enumeration of all possible sets of amino acids and found a set of amino acids whose total fraction in a proteome is correlated, to a remarkable extent, with the OGT. The universal set is Ile, Val, Tyr, Trp, Arg, Glu, Leu (IVYWREL), and the correlation coefficient is as high as 0.93. We also found that the G + C content in 204 complete genomes does not exhibit a significant correlation with OGT (R = -0.10). On the other hand, the fraction of A + G in coding DNA is correlated with temperature, to a considerable extent, due to codon patterns of IVYWREL amino acids. Further, we found strong and independent correlation between OGT and the frequency with which pairs of A and G nucleotides appear as nearest neighbors in genome sequences. This adaptation is achieved via codon bias. These findings present a direct link between principles of proteins structure and stability and evolutionary mechanisms of thermophylic adaptation. On the nucleotide level, the analysis provides an example of how nature utilizes codon bias for evolutionary adaptation to extreme conditions. Together these results provide a complete picture of how compositions of proteomes and genomes in prokaryotes adjust to the extreme conditions of the environment.
Adaptation, Physiological↗