scholarly journals Natural selection and the advantage of recombination

2020 ◽  
Author(s):  
Philip J Gerrish ◽  
Benjamin Galeota-Sprung ◽  
Fernando Cordero ◽  
Paul Sniegowski ◽  
Alexandre Colato ◽  
...  
Keyword(s):  
Natural Selection ◽  
Great Difficulty ◽  
Founder Effects ◽  
Evolutionary Potential ◽  
Heritable Variation ◽  
Number Of Factors ◽  
Population Recombination

The ubiquity of recombination (and sex) in nature has defied explanation since the time of Darwin1–4. Conditions that promote the evolution of recombination, however, are well-understood and arise when genomes contain more selectively mismatched combinations of alleles across loci than can be explained by chance alone. Recombination remedies this across-loci imbalance by shuffling alleles across individuals. The great difficulty in explaining the ubiquity of recombination in nature lies in identifying a source of this imbalance that is comparably ubiquitous. Here, we look to natural selection itself as a possible source of pervasive imbalance, with the rationale that the ubiquity of natural selection approximates the ubiquity of sex and recombination in nature. Natural selection is fed by heritable variation which may be produced by any number of factors, such as drift, founder effects, migration and mutation. We ask how natural selection, acting on this variation, affects the across-loci imbalance and hence the evolutionary potential of recombination. Remarkably, we find that the effect of natural selection is to always promote the evolution of recombination, on average, independently of the source of the variation that feeds it. We show this is true for both across- and within-population recombination. Our findings suggest that recombination evolved and is maintained more as an unavoidable byproduct of natural selection than as a catalyst.

scholarly journals Genetic Variation Explains Changes in Susceptibility in a Naïve Host Against an Invasive Forest Pathogen: The Case of Alder and the Phytophthora alni Complex

2020 ◽  
Vol 110 (2) ◽  
pp. 517-525 ◽  
Author(s):  
Miguel A. Redondo ◽  
Jan Stenlid ◽  
Jonàs Oliva
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Transmission Rate ◽  
Alternative Hypothesis ◽  
Simulated Data ◽  
Alnus Glutinosa ◽  
Heritable Variation ◽  
Narrow Sense Heritability ◽  
Black Alder

Predicting whether naïve tree populations have the potential to adapt to exotic pathogens is necessary owing to the increasing rate of invasions. Adaptation may occur as a result of natural selection when heritable variation in terms of susceptibility exists in the naïve population. We searched for signs of selection on black alder (Alnus glutinosa) stands growing on riverbanks invaded by two pathogens differing in aggressiveness, namely, Phytophthora uniformis (PU) and Phytophthora × alni (PA). We compared the survival and heritability measures from 72 families originating from six invaded and uninvaded (naïve) sites by performing in vitro inoculations. The results from the inoculations were used to assess the relative contribution of host genetic variation on natural selection. We found putative signs of natural selection on alder exerted by PU but not by PA. For PU, we found a higher survival in families originating from invaded sites compared with uninvaded sites. The narrow sense heritability of susceptibility to PU of uninvaded populations was significantly higher than to PA. Simulated data supported the role of heritable genetic variation on natural selection and discarded a high aggressiveness of PA decreasing the transmission rate as an alternative hypothesis for a slow natural selection. Our findings expand on previous attempts of using heritability as a predictor for the likelihood of natural adaptation of naïve tree populations to invasive pathogens. Measures of genetic variation can be useful for risk assessment purposes or when managing Phytophthora invasions.

Generation and the Origin of Species (1837–1937): A Historiographical Suggestion

1989 ◽  
Vol 22 (3) ◽  
pp. 267-281 ◽  
Author(s):  
M. J. S. Hodge
Keyword(s):  
Natural Selection ◽  
History Of Science ◽  
Heritable Variation ◽  
Origin Of Species ◽  
Research And Teaching ◽  
History Of ◽  
The Individual

Bernard Norton's friends in the history of science have had many reasons for commemorating, with admiration and affection, not only his research and teaching but no less his conversation and his company. One of his most estimable traits was his refusal to beat about the bush in raising the questions he thought worthwhile pursuing. I still remember discoursing at Pittsburgh on Darwin's route to his theory of natural selection, and being asked at the end by Bernard what were Darwin's views on heredity. I answered with the conventional waffle to the effect that the theory concerned the populational fate rather than the individual production and transmission of heritable variation, so that whatever views Darwin had on heredity had only a subsidiary place in his theorizing. Bernard was not fooled. ‘I would have thought’, he said, ‘that in order to understand anyone's theorising about evolution it would be necessary to look at his views on heredity’.

Genetic and phenotypic component in head shape of common wall lizard Podarcis muralis

2016 ◽  
Vol 37 (3) ◽  
pp. 301-310 ◽  
Author(s):  
Roberto Sacchi ◽  
Marco Mangiacotti ◽  
Stefano Scali ◽  
Michele Ghitti ◽  
Beatrice Bindolini ◽  
...  
Keyword(s):  
Natural Selection ◽  
Morphological Differentiation ◽  
Phenotypic Change ◽  
Adaptive Responses ◽  
Head Shape ◽  
Heritable Variation ◽  
Podarcis Muralis ◽  
Environmental Pressures ◽  
Common Wall ◽  
Wide Range

Head shape in lizards correlates with a wide range of environmental pressures, supporting the hypothesis that patterns of phenotypic change represent adaptive responses to selective processes. However, natural selection promotes evolutionary adaptation only if the trait under selection has enough heritable variation. In this study we used geometric morphometrics and quantitative genetics to assess the heritability patterns of the head shape and size of common wall lizards (Podarcis muralis). Genetic and phenotypic components were estimated using animal models, which showed that more than half of the variation in head morphology is inheritable. Furthermore, at least five independent patterns of genetically determined phenotypic change were detected. These outcomes confirm that morphological differentiation in common wall lizards may reliably be regarded as the result of adaptive processes driven by natural selection.

scholarly journals Natural Selection beyond Life? A Workshop Report

Life ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1051
Author(s):  
Sylvain Charlat ◽  
André Ariew ◽  
Pierrick Bourrat ◽  
María Ferreira Ruiz ◽  
Thomas Heams ◽  
...  
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Dissipative Structures ◽  
Heritable Variation ◽  
Physical Systems ◽  
Research Fields ◽  
Physico Chemical ◽  
Biological Concepts ◽  
Evolution By Natural Selection ◽  
Physical Phenomena

Natural selection is commonly seen not just as an explanation for adaptive evolution, but as the inevitable consequence of “heritable variation in fitness among individuals”. Although it remains embedded in biological concepts, such a formalisation makes it tempting to explore whether this precondition may be met not only in life as we know it, but also in other physical systems. This would imply that these systems are subject to natural selection and may perhaps be investigated in a biological framework, where properties are typically examined in light of their putative functions. Here we relate the major questions that were debated during a three-day workshop devoted to discussing whether natural selection may take place in non-living physical systems. We start this report with a brief overview of research fields dealing with “life-like” or “proto-biotic” systems, where mimicking evolution by natural selection in test tubes stands as a major objective. We contend the challenge may be as much conceptual as technical. Taking the problem from a physical angle, we then discuss the framework of dissipative structures. Although life is viewed in this context as a particular case within a larger ensemble of physical phenomena, this approach does not provide general principles from which natural selection can be derived. Turning back to evolutionary biology, we ask to what extent the most general formulations of the necessary conditions or signatures of natural selection may be applicable beyond biology. In our view, such a cross-disciplinary jump is impeded by reliance on individuality as a central yet implicit and loosely defined concept. Overall, these discussions thus lead us to conjecture that understanding, in physico-chemical terms, how individuality emerges and how it can be recognised, will be essential in the search for instances of evolution by natural selection outside of living systems.

scholarly journals Adaptation to a novel predator inDrosophila melanogaster: How well are we able to predict evolutionary responses?

2014 ◽  
Author(s):  
Michael DeNieu ◽  
William Pitchers ◽  
Ian Dworkin
Keyword(s):  
Natural Selection ◽  
Experimental Evolution ◽  
Phenotypic Selection ◽  
Ancestral Population ◽  
Wing Size ◽  
Short Term ◽  
Heritable Variation ◽  
Size And Shape ◽  
Evolutionary Trajectories ◽  
Short Term Prediction

Evolutionary theory is sufficiently well developed to allow for short-term prediction of evolutionary trajectories. In addition to the presence of heritable variation, prediction requires knowledge of the form of natural selection on relevant traits. While many studies estimate the form of natural selection, few examine the degree to which traits evolve in the predicted direction. In this study we examine the form of natural selection imposed by mantid predation on wing size and shape in the fruitfly,Drosophila melanogaster. We then evolve populations ofD. melanogasterunder predation pressure, and examine the extent to which wing size and shape have responded in the predicted direction. We demonstrate that wing form partially evolves along the predicted vector from selection, more so than for control lineages. Furthermore, we re-examined phenotypic selection after ~30 generations of experimental evolution. We observed that the magnitude of selection on wing size and shape was diminished in populations evolving with mantid predators, while the direction of the selection vector differed from that of the ancestral population for shape. We discuss these findings in the context of the predictability of evolutionary responses, and the need for fully multivariate approaches.

scholarly journals Mendel and Darwin: untangling a persistent enigma

Heredity ◽  
2019 ◽  
Vol 124 (2) ◽  
pp. 263-273
Author(s):  
Daniel J. Fairbanks
Keyword(s):  
Natural Selection ◽  
Darwinian Evolution ◽  
Heritable Variation ◽  
Outright Rejection ◽  
Scientific Environment ◽  
Final Letter

AbstractMendel and Darwin were contemporaries, with much overlap in their scientifically productive years. Available evidence shows that Mendel knew much about Darwin, whereas Darwin knew nothing of Mendel. Because of the fragmentary nature of this evidence, published inferences regarding Mendel’s views on Darwinian evolution are contradictory and enigmatic, with claims ranging from enthusiastic acceptance to outright rejection. The objective of this review is to examine evidence from Mendel’s published and private writings on evolution and Darwin, and the influence of the scientific environment in which he was immersed. Much of this evidence lies in Mendel’s handwritten annotations in his copies of Darwin’s books, which this review scrutinises in detail. Darwin’s writings directly influenced Mendel’s classic 1866 paper, and his letters to Nägeli. He commended and criticised Darwin on specific issues pertinent to his research, including the provisional hypothesis of pangenesis, the role of pollen in fertilisation, and the influence of “conditions of life” on heritable variation. In his final letter to Nägeli, Mendel proposed a Darwinian scenario for natural selection using the same German term for “struggle for existence” as in his copies of Darwin’s books. His published and private scientific writings are entirely objective, devoid of polemics or religious allusions, and address evolutionary questions in a manner consistent with that of his scientific contemporaries. The image that emerges of Mendel is of a meticulous scientist who accepted the tenets of Darwinian evolution, while privately pinpointing aspects of Darwin’s views of inheritance that were not supported by Mendel’s own experiments.

scholarly journals Heritable spouse effects increase evolutionary potential of human reproductive timing

2018 ◽  
Vol 285 (1876) ◽  
pp. 20172763
Author(s):  
Simon R. Evans ◽  
Dominique Waldvogel ◽  
Nina Vasiljevic ◽  
Erik Postma
Keyword(s):  
Life Histories ◽  
Genetic Effect ◽  
Age At First Birth ◽  
Reproductive Timing ◽  
Evolutionary Potential ◽  
Heritable Variation ◽  
Indirect Genetic Effect ◽  
Component Traits ◽  
Human Reproductive ◽  
Female Specific

Sexual reproduction is inherently interactive, especially in animal species such as humans that exhibit extended pair bonding. Yet we have little knowledge of the role of male characteristics and their evolutionary impact on reproductive behavioural phenotypes, to the extent that biologists typically consider component traits (e.g. reproductive timing) as female-specific. Based on extensive genealogical data detailing the life histories of 6435 human mothers born across four centuries of modern history, we use an animal modelling approach to estimate the indirect genetic effect of men on the reproductive phenotype of their partners. These analyses show that a woman's reproductive timing (age at first birth) is influenced by her partner's genotype. This indirect genetic effect is positively correlated with the direct genetic effect expressed in women, such that total heritable variance in this trait is doubled when heritable partner effects are considered. Our study thus suggests that much of the heritable variation in women's reproductive timing is mediated via partner effects, and that the evolutionary potential of this trait is far greater than previously appreciated.

scholarly journals Indirect genetic effects underlie oxygen-limited thermal tolerance within a coastal population of chinook salmon

2014 ◽  
Vol 281 (1789) ◽  
pp. 20141082 ◽  
Author(s):  
Nicolas J. Muñoz ◽  
Katja Anttila ◽  
Zhongqi Chen ◽  
John W. Heath ◽  
Anthony P. Farrell ◽  
...  
Keyword(s):  
Maternal Effects ◽  
Chinook Salmon ◽  
Thermal Tolerance ◽  
Egg Size ◽  
Oncorhynchus Tshawytscha ◽  
Genetic Effects ◽  
Adaptation To Climate Change ◽  
Evolutionary Potential ◽  
Heritable Variation ◽  
Indirect Genetic Effects

With global temperatures projected to surpass the limits of thermal tolerance for many species, evaluating the heritable variation underlying thermal tolerance is critical for understanding the potential for adaptation to climate change. We examined the evolutionary potential of thermal tolerance within a population of chinook salmon ( Oncorhynchus tshawytscha ) by conducting a full-factorial breeding design and measuring the thermal performance of cardiac function and the critical thermal maximum (CT max ) of offspring from each family. Additive genetic variation in offspring phenotype was mostly negligible, although these direct genetic effects explained 53% of the variation in resting heart rate ( f H ). Conversely, maternal effects had a significant influence on resting f H , scope for f H , cardiac arrhythmia temperature and CT max . These maternal effects were associated with egg size, as indicated by strong relationships between the mean egg diameter of mothers and offspring thermal tolerance. Because egg size can be highly heritable in chinook salmon, our finding indicates that the maternal effects of egg size constitute an indirect genetic effect contributing to thermal tolerance. Such indirect genetic effects could accelerate evolutionary responses to the selection imposed by rising temperatures and could contribute to the population-specific thermal tolerance that has recently been uncovered among Pacific salmon populations.

scholarly journals Evolutionary plant breeding for low input systems

2005 ◽  
Vol 143 (4) ◽  
pp. 245-254 ◽  
Author(s):  
S. L. PHILLIPS ◽  
M. S. WOLFE
Keyword(s):  
Natural Selection ◽  
Gene Pools ◽  
Heritable Variation ◽  
Low Input ◽  
Pests And Diseases ◽  
Evolutionary Origins ◽  
Crop Varieties ◽  
Pure Lines ◽  
And Control ◽  
Selection Of

Heritable variation is at the heart of the process of evolution. However, variation is restricted in breeding for uniform crop populations using the pedigree line approach. Pedigree lines are successful in agriculture because synthetic inputs are used to raise fertility and control weeds, pests and diseases. An alternative method promoted for exploring the value of variation and evolutionary fitness in crops is to create composite cross populations. Composite cross populations are formed by assembling seed stocks with diverse evolutionary origins, recombination of these stocks by hybridization, the bulking of F1 progeny, and subsequent natural selection for mass sorting of the progeny in successive natural cropping environments. Composite cross populations can provide dynamic gene pools, which in turn provide a means of conserving germplasm resources: they can also allow selection of heterogeneous crop varieties. The value of composite cross populations in achieving these aims is dependent on the outcome of mass trials by artificial and natural selection acting upon the heterogeneous mixture. There is evidence to suggest that composite cross populations may be an efficient way of providing heterogeneous crops and of selecting superior pure lines for low input systems characterized by unpredictable stress conditions.

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