scholarly journals The microbiome extends host evolutionary potential

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lucas P. Henry ◽  
Marjolein Bruijning ◽  
Simon K. G. Forsberg ◽  
Julien F. Ayroles
Keyword(s):  
Quantitative Genetics ◽  
Host Response ◽  
Evolutionary Models ◽  
Response To Selection ◽  
Evolutionary Potential ◽  
Complex Interplay ◽  
The Mean

AbstractThe microbiome shapes many host traits, yet the biology of microbiomes challenges traditional evolutionary models. Here, we illustrate how integrating the microbiome into quantitative genetics can help untangle complexities of host-microbiome evolution. We describe two general ways in which the microbiome may affect host evolutionary potential: by shifting the mean host phenotype and by changing the variance in host phenotype in the population. We synthesize the literature across diverse taxa and discuss how these scenarios could shape the host response to selection. We conclude by outlining key avenues of research to improve our understanding of the complex interplay between hosts and microbiomes.

scholarly journals Selection, Load and Inbreeding Depression in a Large Metapopulation

Genetics ◽  
2002 ◽  
Vol 160 (3) ◽  
pp. 1191-1202 ◽  
Author(s):  
Michael C Whitlock
Keyword(s):  
Population Structure ◽  
Inbreeding Depression ◽  
Population Subdivision ◽  
Response To Selection ◽  
Mutation Load ◽  
Deleterious Alleles ◽  
Subdivided Population ◽  
Soft Selection ◽  
Mean Fitness ◽  
The Mean

Abstract The subdivision of a species into local populations causes its response to selection to change, even if selection is uniform across space. Population structure increases the frequency of homozygotes and therefore makes selection on homozygous effects more effective. However, population subdivision can increase the probability of competition among relatives, which may reduce the efficacy of selection. As a result, the response to selection can be either increased or decreased in a subdivided population relative to an undivided one, depending on the dominance coefficient FST and whether selection is hard or soft. Realistic levels of population structure tend to reduce the mean frequency of deleterious alleles. The mutation load tends to be decreased in a subdivided population for recessive alleles, as does the expected inbreeding depression. The magnitude of the effects of population subdivision tends to be greatest in species with hard selection rather than soft selection. Population structure can play an important role in determining the mean fitness of populations at equilibrium between mutation and selection.

scholarly journals Aggregatibacter Actinomycetemcomitans: Clinical Significance of a Pathobiont Subjected to Ample Changes in Classification and Nomenclature

2019 ◽  
Author(s):  
Niels Nørskov-Lauritsen ◽  
Rolf Claesson ◽  
Anne Birkeholm Jensen ◽  
Carola Höglund-Åberg ◽  
Dorte Haubek
Keyword(s):  
Clinical Significance ◽  
Host Response ◽  
Aggregatibacter Actinomycetemcomitans ◽  
Oral Microbiota ◽  
Aetiological Agent ◽  
Negative Bacterium ◽  
Complex Interplay ◽  
Gram Negative ◽  
Oral Infections ◽  
Exclusive Or

Aggregatibacter actinomycetemcomitans is a Gram-negative bacterium that is part of the oral microbiota. The aggregative nature of this pathogen or pathobiont is crucial to its involvement in human disease. It has been cultured from non-oral infections for more than a century, while the portrayal as an aetiological agent in periodontitis has emerged more recently. Although A. actinomycetemcomitans encodes several putative toxins, the complex interplay with other partners of the oral microbiota and the suppression of the initial host response may be central for inflammation and infection in the oral cavity. The aim of this review is to provide a comprehensive update on the clinical significance, classification, and characterisation of A. actinomycetemcomitans, which has exclusive or predominant host specificity for humans.

scholarly journals Meta-analysis suggests the microbiome responds to Evolve and Resequence experiments in Drosophila melanogaster

2020 ◽  
Author(s):  
Lucas P Henry ◽  
Julien F Ayroles
Keyword(s):  
Drosophila Melanogaster ◽  
Bacterial Diversity ◽  
Experimental Evolution ◽  
Host Selection ◽  
Host Response ◽  
Meta Analysis ◽  
Response To Selection ◽  
Evolutionary Processes ◽  
History Of ◽  
Host Evolution

Experimental evolution has a long history of uncovering fundamental insights into evolutionary processes but has largely neglected one underappreciated component--the microbiome. As eukaryotic hosts evolve, the microbiome may also evolve in response. However, the microbial contribution to host evolution remains poorly understood. Here, we analyzed the metagenomes from 10 E&R experiments in Drosophila melanogaster to determine how the microbiome changes in response to host selection. Bacterial diversity was significantly different in 5/10 studies in traits associated with metabolism or immunity. Additionally, we find that excluding reads from a facultative symbiont, Wolbachia, in the analysis of bacterial diversity changes the inference, raising important questions for future E&R experiments in D. melanogaster. Our results suggest the microbiome often responds to host selection but highlights the need for more work to understand how the microbiome changes the host response to selection.

scholarly journals Marker-assisted selection using ridge regression

2000 ◽  
Vol 75 (2) ◽  
pp. 249-252 ◽  
Author(s):  
JOHN C. WHITTAKER ◽  
ROBIN THOMPSON ◽  
MIKE C. DENHAM
Keyword(s):  
Linear Regression ◽  
Ridge Regression ◽  
Marker Assisted Selection ◽  
Quantitative Traits ◽  
Selection Response ◽  
Inbred Lines ◽  
Response To Selection ◽  
Satisfactory Method ◽  
The Mean ◽  
Selection Of

In crosses between inbred lines, linear regression can be used to estimate the correlation of markers with a trait of interest; these marker effects then allow marker assisted selection (MAS) for quantitative traits. Usually a subset of markers to include in the model must be selected: no completely satisfactory method of doing this exists. We show that replacing this selection of markers by ridge regression can improve the mean response to selection and reduce the variability of selection response.

scholarly journals Multilevel Selection 1: Quantitative Genetics of Inheritance and Response to Selection: TABLE 1

Genetics ◽  
2006 ◽  
Vol 175 (1) ◽  
pp. 277-288 ◽  
Author(s):  
Piter Bijma ◽  
William M. Muir ◽  
Johan A. M. Van Arendonk
Keyword(s):  
Quantitative Genetics ◽  
Multilevel Selection ◽  
Response To Selection

Invasive fungal infections are associated with severe depletion of circulating RANTES

2005 ◽  
Vol 54 (11) ◽  
pp. 1017-1022 ◽  
Author(s):  
Michael Ellis ◽  
Basel al-Ramadi ◽  
Ulla Hedström ◽  
Hussain Alizadeh ◽  
Victor Shammas ◽  
...  
Keyword(s):  
T Cell ◽  
Fungal Infection ◽  
Invasive Fungal Infection ◽  
Host Response ◽  
Fungal Infections ◽  
Invasive Fungal Infections ◽  
Time Of Death ◽  
Haematological Malignancies ◽  
Platelet Counts ◽  
The Mean

Serum RANTES (regulated on activation, normal T-cell expressed and secreted) concentrations were measured in 14 patients who had haematological malignancies and developed invasive fungal infections (three of them definite, eight probable and three possible). RANTES levels fell substantially from pre-chemotherapy values at the start of and throughout the fungal infection, and recovered in patients who survived the fungal infection. However, in patients who died from the invasive fungal infection, RANTES levels did not recover. For survivors the mean ± sd levels for RANTES were 7656 ± 877 pg ml−1 on the day prior to chemotherapy, 3723 ± 2443 pg ml−1 on the first day of fungal infection diagnosis (significantly different from baseline; P = 0.001) and 9078 ± 2256 pg ml−1 at recovery from the fungal infection (significantly different from lowest value; P < 0.0001). Platelet counts were closely correlated with the RANTES levels (r = 0.63, P < 0.001). The RANTES concentrations for the three patients who died were similar to those who survived at all equivalent timepoints, but were significantly lower at the time of death (792 ± 877) compared to the values at recovery for survivors (P = 0.005). The finding that patients who died from an invasive fungal infection had very low platelet counts and RANTES concentrations suggests that these could play a role in host response to such infections.

Measurement of fleece wettability in sheep and its relationship to susceptibility to fleece rot and blowfly strike

1982 ◽  
Vol 33 (1) ◽  
pp. 141 ◽  
Author(s):  
L Pascoe
Keyword(s):  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Genetic Correlations ◽  
Economic Importance ◽  
Correlated Response ◽  
Response To Selection ◽  
Significant Incidence ◽  
The Mean ◽  
Selection For ◽  
The One

Fleece wettability in sheep is a character believed to be related to susceptibility to fleece rot and blowfly strike. The present study was undertaken to investigate that hypothesis and to assess wettability as a possible character for a selection program. Wool samples were taken from two flocks which had been subject to selection for wool quality and resistance to fleece rot and a third flock which was unselected. The wettabilities of about 800 samples were determined. The results were found to be repeatable and the technique was capable of distinguishing between sheep. Some problems of measurement are discussed. In the one flock with a significant incidence of fleece rot, susceptibility to fleece rot was found to be associated with higher wettabilities. The mean wettability and the variance were found to be significantly higher in the unselected flock than in the two selected flocks. The heritability of wettability was estimated in the two selected flocks and was found to be low. It is argued that there is likely to be more additive genetic variance in the unselected flock and that the observed difference in wettability was due to a correlated response to selection for resistance to fleece rot. It is considered that further work on the heritability of wettability and its genetic correlations with other characters of economic importance could be fruitful.

scholarly journals Parameters and determinants of responses to selection in antibody libraries

2019 ◽  
Author(s):  
Steven Schulz ◽  
Sébastien Boyer ◽  
Matteo Smerlak ◽  
Simona Cocco ◽  
Rémi Monasson ◽  
...  
Keyword(s):  
Adaptive Immune Response ◽  
Evolutionary Process ◽  
Affinity Maturation ◽  
Target Antigen ◽  
Response To Selection ◽  
Evolutionary Potential ◽  
Information Theoretic ◽  
Antibody Libraries ◽  
The Impact ◽  
Selection Of

AbstractAntibody repertoires contain binders to nearly any target antigen. The sequences of these antibodies differ mostly at few sites located on the surface of a scaffold that itself consists of much less varied amino acids. What is the impact of this scaffold on the response to selection of a repertoire? To gauge this impact, we carried out quantitative phage display experiments with three antibody libraries based on distinct scaffolds harboring the same diversity at randomized sites, which we selected for binding to four arbitrary targets. We first show that the response to selection of an antibody library is captured by a simple and measurable parameter with direct physical and information-theoretic interpretations. Second, we identify a major determinant of this parameter which is encoded in the scaffold, its degree of evolutionary maturation. Antibodies undergo an accelerated evolutionary process, called affinity maturation, to improve their affinity to a given target antigen as part of the adaptive immune response. We find that libraries of antibodies built around such maturated scaffolds have a lower response to selection to other arbitrary targets than libraries built around naïve scaffolds of germline origin. Our results are a first step towards quantifying and controlling the evolutionary potential of biomolecules.

scholarly journals Thermal physiology and thermoregulatory behaviour exhibit low heritability despite genetic divergence between lizard populations

2018 ◽  
Vol 285 (1878) ◽  
pp. 20180697 ◽  
Author(s):  
Michael L. Logan ◽  
John David Curlis ◽  
Anthony L. Gilbert ◽  
Donald B. Miles ◽  
Albert K. Chung ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Genetic Divergence ◽  
Common Garden ◽  
Response To Selection ◽  
Thermal Physiology ◽  
Evolutionary Potential ◽  
Thermal Environments ◽  
Performance Curves ◽  
Brown Anole ◽  
Thermoregulatory Behaviour

Ectothermic species are particularly sensitive to changes in temperature and may adapt to changes in thermal environments through evolutionary shifts in thermal physiology or thermoregulatory behaviour. Nevertheless, the heritability of thermal traits, which sets a limit on evolutionary potential, remains largely unexplored. In this study, we captured brown anole lizards ( Anolis sagrei ) from two populations that occur in contrasting thermal environments. We raised offspring from these populations in a laboratory common garden and compared the shape of their thermal performance curves to test for genetic divergence in thermal physiology. Thermal performance curves differed between populations in a common garden in ways partially consistent with divergent patterns of natural selection experienced by the source populations, implying that they had evolved in response to selection. Next, we estimated the heritability of thermal performance curves and of several traits related to thermoregulatory behaviour. We did not detect significant heritability in most components of the thermal performance curve or in several aspects of thermoregulatory behaviour, suggesting that contemporary selection is unlikely to result in rapid evolution. Our results indicate that the response to selection may be slow in the brown anole and that evolutionary change is unlikely to keep pace with current rates of environmental change.

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