Mirre J P Simons

Mirre J P Simons
The University of Sheffield | Sheffield · Department of Animal and Plant Sciences

PhD

About

80
Publications
89,505
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1,457
Citations
Additional affiliations
May 2013 - July 2015
The University of Sheffield
Position
  • PostDoc Position
October 2008 - February 2013
University of Groningen
Position
  • PhD Student

Publications

Publications (80)
Article
Full-text available
Multiple studies have demonstrated that telomere length predicts mortality and that telomeres shorten with age. Although rarely acknowledged these associations do not dictate causality. I review telomerase knockout and overexpression studies and find little support that telomeres cause aging. In addition, the causality hypothesis assumes that there...
Article
Full-text available
Reduced mechanistic target of rapamycin (mTOR) signalling extends lifespan in yeast, nematodes, fruit flies and mice, highlighting a physiological pathway that could modulate aging in evolutionarily divergent organisms. This signalling system is also hypothesized to play a central role in lifespan extension via dietary restriction. By collating dat...
Article
Full-text available
Telomeres are highly conserved regions of DNA that protect the ends of linear chromosomes. The loss of telomeres can signal an irreversible change to a cell's state, including cellular senescence. Senescent cells no longer divide and can damage nearby healthy cells, thus potentially placing them at the crossroads of cancer and ageing. While the epi...
Preprint
Full-text available
Dietary restriction (DR) consistently and universally extends health- and lifespan across taxa. Despite efforts to uncover the mechanisms underpinning DR - and ultimately translate its beneficial outcomes to humans - precise and universal mechanisms have not been identified. In biomedical science, the effects of DR are interpreted as regulating pro...
Preprint
Full-text available
Life-history theory, central to our understanding of diversity in morphology, behaviour and senescence, describes how traits evolve through the optimisation of trade-offs in investment. Despite considerable study, there is only minimal support for trade-offs within species between the two traits most closely linked to fitness - reproduction and sur...
Article
Full-text available
Offspring of older parents in many species have decreased longevity, a faster ageing rate and lower fecundity than offspring born to younger parents. Biomarkers of ageing, such as telomeres, that tend to shorten as individuals age, may provide insight into the mechanisms of such parental age effects. Parental age may be associated with offspring te...
Article
Dietary restriction (DR) is one of the most potent ways to extend health- and lifespan. Key progress in understanding the mechanisms of DR, and ageing more generally, was made when dietary protein, and more specifically essential amino acids (EAA), were identified as the dietary component to restrict to obtain DR’s health and lifespan benefits. Thi...
Preprint
Full-text available
Variants of SARS-CoV2 that achieved global dominance (Alpha and Delta) have been associated with increased hospitalisation risk. A quantification of this risk across studies is currently lacking for Delta. Furthermore, how risk for severe disease changes in both vaccinated and unvaccinated individuals is important as the underlying risks determine...
Article
Full-text available
Costs of reproduction shape the life-history evolution of investment in current and future reproduction and thereby aging. Androgens have been proposed to regulate the physiology governing these investments. Furthermore, androgens are hypothesized to play a central role in carotenoid-dependent sexual signaling, regulating how much carotenoids are d...
Preprint
Full-text available
Dietary restriction (DR) is one of the most potent ways to extend health- and lifespan. Key progress in understanding the mechanisms of DR, and ageing more generally, was made when dietary protein, and more specifically essential amino acids (EAA), were identified as the key dietary component to restrict to obtain DRs health and lifespan benefits....
Preprint
Full-text available
Offspring of older parents in many species display decreased longevity, a faster ageing rate and lower fecundity than offspring born to younger parents. Biomarkers, such as telomeres, that tend to shorten as individual age, may provide insight into the mechanisms of parental age effects. Parental age could determine telomere length either through i...
Article
Full-text available
Dietary restriction (DR) is a key focus in ageing research. Specific conditions and genotypes were recently found to negate lifespan extension by DR, questioning its universal relevance. However, the concept of dietary reaction norms explains why DR's effects might be obscured in some situations. We tested the importance of dietary reaction norms b...
Article
Full-text available
1.The longitudinal study of populations is a core tool for understanding ecological and evolutionary processes. Long‐term studies typically collect samples repeatedly over individual lifetimes and across generations. These samples are then analysed in batches (e.g. qPCR‐plates) and clusters (i.e. group of batches) over time in the laboratory. Howev...
Article
Full-text available
Dietary restriction (DR) extends life span across taxa. Despite considerable research, universal mechanisms of DR have not been identified, limiting its translational potential. Guided by the conviction that DR evolved as an adaptive, pro-longevity physiological response to food scarcity, biomedical science has interpreted DR as an activator of pro...
Preprint
Full-text available
Dietary restriction (DR) is a key focus in ageing research. Specific conditions and genotypes were recently found to negate lifespan extension by DR, questioning the universal relevance of DR. However, the conceptual framework of dietary reaction norms explains why DRs effects might not be apparent in some situations. When dietary reaction norms sh...
Article
Full-text available
In some eukaryotes, germline and somatic genomes differ dramatically in their composition. Here we characterise a major germline–soma dissimilarity caused by a germline-restricted chromosome (GRC) in songbirds. We show that the zebra finch GRC contains >115 genes paralogous to single-copy genes on 18 autosomes and the Z chromosome, and is enriched...
Preprint
Full-text available
Research on the mechanisms of ageing has identified ways via which lifespan can be extended in model organisms, increasing the potential for translation of these findings to our own species. However, the large majority of research on animal models involves dietary, genetic or pharmacological treatments throughout life - limiting translational poten...
Preprint
Full-text available
Variation in individual life histories, and physiology, determines the rates at which new life is generated (reproduction) and lost (death) in a population. Studying the demography of deaths thus reveals fundamental aspects of the biology of individuals within a population. We studied mortality senescence, the increase in mortality rate with age, i...
Preprint
The longitudinal study of populations is a core tool for understanding ecological and evolutionary processes. These studies typically collect samples over individual lifetimes and across multiple generations, building up a continuously growing biobank from which samples are then analysed in clusters over time in the laboratory. To ensure data are c...
Article
Full-text available
Reproduction is predicted to trade-off with long-term maternal survival, but the survival costs often vary between individuals, cohorts and populations, limiting our understanding of this trade-off, which is central to life-history theory. One potential factor generating variation in reproductive costs is variation in developmental conditions, but...
Data
Individual-level information for cox models on number of children born and maternal survival. (CSV)
Data
Individual-level information for cox models on number of children survived to adulthood and maternal survival. (CSV)
Data
File containing Figure A explaining conception behind calculation of mean rye for a period which covers pregnancy and first year of life and Tables A-F with mixed-effects Cox regression models of the effects of number of children born and survived to adulthood (respectively) and early-life environment (rye yields, spring temperature, infant mortali...
Preprint
Full-text available
Genomes can vary within individual organisms. Programmed DNA elimination leads to dramatic changes in genome organisation during the germline-soma differentiation of ciliates, lampreys, nematodes, and various other eukaryotes. A particularly remarkable example of tissue-specific genome differentiation is the germline-restricted chromosome (GRC) in...
Article
Full-text available
The Smurf Assay (SA) was initially developed in the model organism Drosophila melanogaster where a dramatic increase of intestinal permeability has been shown to occur during ageing. We have since validated the protocol in multiple other model organisms and have utilised the assay to further our understanding of ageing. The SA has now also been use...
Article
Full-text available
Finding a high quality territory is essential for many animals to reproduce successfully. Despite its importance for fitness, we know little about the process of territory prospecting in wild birds, and whether individual traits and behaviours, such as personality, co-vary with territory prospecting. Here, we use long-term data from a wild, insular...
Article
Full-text available
Reduced somatotrophic signaling through the growth hormone (GH) and insulin-like growth factor pathways (IGF1) can delay aging, although the degree of life-extension varies markedly across studies. By collating data from previous studies and using meta-analysis, we tested whether factors including sex, hormonal manipulation, body weight change and...
Article
Full-text available
Reproductive success is associated with age in many taxa, increasing in early life followed by reproductive senescence. In socially monogamous, but genetically polygamous species, this generates the interesting possibility of differential trajectories of within-pair and extra-pair siring success with age in males. We investigate these relationships...
Article
Full-text available
Objectives: The study of assortative mating for height has a rich history in human biology. Although the positive correlation between the stature of spouses has often been noted in western populations, recent papers suggest that mating patterns for stature are not universal. The objective of this paper was to review the published evidence to exami...
Article
One predicted cost of female infidelity in socially monogamous species is that cuckolded males should provide less parental care. This relationship is robust across species, but evidence is ambiguous within species. We do not know whether individual males reduce their care when paired with cheating females compared with when paired with faithful fe...
Article
Full-text available
Senescence is a decrease in functional capacity, increasing mortality rate with age. Sexual signals indicate functional capacity, because costs of ornamentation ensure signal honesty, and are therefore expected to senesce, tracking physiological deterioration and mortality. For sexual traits, mixed associations with age and positive associations wi...
Article
Full-text available
Selectively logged tropical forests retain high species richness and functional diversity, but species composition changes after logging, suggesting that some species are more vulnerable to logging than others. We did a meta-analysis to summarise the effect of logging on the abundance of individual bird and mammal species in tropical forests of Bor...
Article
Full-text available
Life-history theory concerns the trade-offs that mold the patterns of investment by animals between reproduction, growth, and survival. It is widely recognized that physiology plays a role in the mediation of life-history trade-offs, but the details remain obscure. As life-history theory concerns aspects of investment in the soma that influence sur...
Presentation
Full-text available
Finding a good nest site is essential for birds. However, the process of nest prospecting is not well described in wild populations. Here, we use a long-term dataset to test two hypotheses regarding winter nest prospecting behaviour: (1) first-time breeders show higher winter nest prospecting behaviour than older individuals, who most likely alread...
Article
Full-text available
Animal research often relies on catching wild animals; however, individuals may have different trappability, and this can generate bias. We studied bias in mist netting, the main method for catching wild birds. The unusually high resighting rate in our study population—house sparrows (Passer domesticus) on Lundy Island (England)—allowed us to obtai...
Article
Full-text available
The vitamin A-redox hypothesis provides an explanation for honest signaling of phenotypic quality by carotenoid-dependent traits. A key aspect of the vitamin A-redox hypothesis, applicable to both yellow and red coloration, is the hypothesized negative feedback of tightly regulated Vitamin A plasma levels on the enzyme responsible for sequestering...
Article
Full-text available
Sexual selection has resulted in a wide array of ornaments used in mate choice, and such indicator traits signal quality honestly when they bear costs, precluding cheating. Carotenoid-dependent coloration has attracted considerable attention in this context, because investing carotenoids in coloration has to be traded off against its physiological...
Article
Full-text available
Carotenoid-dependent sexual coloration is one of the best-studied sexual signals, but how the honesty of such signals is maintained remains uncertain. The main hypotheses focus on acquisition limits, and physiological use of carotenoids in immune function and regulating oxidative stress. A hypothesis that has received less attention states that car...
Article
Full-text available
Human cortisol levels follow a clear circadian rhythm. We investigated the contribution of alternation of sleep and wakefulness and the circadian clock, using forced desynchrony. Cortisol levels were best described by a multiplication of a circadian and a wake-time component. The human cortisol response is modulated by circadian phase. Exposure to...
Article
Full-text available
Telomere length and the rate of telomere attrition vary between individuals and have been interpreted as the rate at which individuals have aged. The biology of telomeres dictates shortening with age, although telomere elongation with age has repeatedly been observed within a minority of individuals in several populations. These findings have been...
Article
Full-text available
Dietary restriction (DR) extends lifespan in multiple species from various taxa. This effect can arise via two distinct but not mutually exclusive ways: a change in aging rate and/or vulnerability to the aging process (i.e. initial mortality rate). When DR affects vulnerability, this lowers mortality instantly, whereas a change in aging rate will g...
Article
Full-text available
Biomarkers of aging are essential to predict mortality and aging related diseases. Paradoxically, age itself imposes a limitation on the use of known biomarkers of aging, because their associations with mortality generally diminish with age. How this pattern arises is however not understood. With meta-analysis we show that human leucocyte telomere...
Data
Biomarkers of aging are essential to predict mortality and aging-related diseases. Paradoxically, age itself imposes a limitation on the use of known biomarkers of aging because their associations with mortality generally diminish with age. How this pattern arises is, however, not understood. With meta-analysis we show that human leucocyte telomere...
Article
Full-text available
Mechanisms maintaining honesty of sexual signals are far from resolved, limiting our understanding of sexual selection and potential important parts of physiology. Carotenoid pigmented visual signals are among the most extensively studied sexual displays, but evidence regarding hypotheses on how carotenoids ensure signal honesty is mixed. Using a p...
Data
Full-text available
Plotted in the order of table 1 and data S1 are the separate datasets of effect sizes plotted against their corresponding sample sizes. The title depicts the relationship plotted. (PDF)
Data
Excel file of the datasets collected for the separate meta-analyses. (XLSX)