Double GELIFES lustrum!
1st Adaptive Life lustrum - Postponed, new date to be announced
This year, the Adaptive Life research programme has been succesfully running for five years. In this 1st lustrum symposium we will portray the PhD projects that were specifically made possible due to the generous funding by the University and Faculty for the Adaptive Life programme, as well as all other projects that fall under the Adaptive Life umbrella.
|09:15||Opening Ton Groothuis|
|09:30||Martijn Schenkel: Evolution of multifactorial sex determination along an environmental gradient|
|09:45||Apu Ramesh: Migration syndromes in three-spined sticklebacks|
|10:00||Anne-Marie Veenstra-Skirl: Mutational influence on the evolution of resistance to the antimicrobial peptide nisin in Lactococcus lactis|
|10:45||Elodie Wilwert: Where I go is what I see?|
|11:00||Sasirekha Munikumar: Endophytic fungi-mediated abiotic stress tolerance in bittersweet|
|11:15||Natalie van Dis: Microevolution in action - Mechanism of adaptation to climate change in the winter moth|
|11:30||Raphael Scherrer: The genomic architecture of adaptive speciation|
|12:00||Tiphaine Bailly: Social modulation of egg-laying in Drosophila melanogaster|
|12:15||Sjoerd van Hasselt: The ecology of sleep - New insights on sleep homeostasis from EEG studies in barnacle geese|
|12:30||Pratik Gupte: Causes and consequences of animal movement|
|12:45||Selin Ersoy: Across context consistency in individual movement behaviour of red knots (Calidris canutus)|
|15:45||Merijn Driessen: Mosaic ageing of the immune system in zebra finches|
|16:00||Yoran Gerritsma: The developmental plasticity of personality traits in zebra finches|
|16:15||Plenary discussion on AL’s future|
|17:00||Closure & Tea break|
Supervisors: Leo Beukeboom, Ido Pen, Jean-Christophe Billeter
Evolution of multifactorial sex determination along an environmental gradient
Sex determination (SD) is an essential developmental process, but the mechanisms by which it is regulated are very diverse. SD mechanisms are generally categorized according to the type of initial regulatory signals involved, which may be genetic (GSD) or environmental (ESD). In many GSD systems, environmental conditions can still affect SD, e.g. when increased temperatures causes individuals to develop into females despite having a male genotype. It is unclear how such SD systems evolve, and under what conditions this results in between-population differentiation in SD mechanisms within a single species. We have developed a theoretical model based on the multifactorial sex determination system of the Housefly Musca domestica to study the evolution of such systems. In our model, temperature positively affects the activity of a female-determining gene F, which generates a product that induces female development. Male development is induced by breakdown of F product by a product derived from a second gene called M. Our model features a number of subpopulations distributed across a linear gradient in which temperature increases from one end to the other, so that F activity is differently affected in each subpopulation. I will discuss this model and its predictions, such as how environmental influences on SD affect the evolution of GSD mechanisms and under what conditions this can lead to the evolution of different SD mechanisms in a single species.
Supervisors: Franjo Weissing, Marion Nicolaus, Ton Groothuis
Migration syndromes in three-spined sticklebacks
It is widely accepted that animals of the same populations differ consistently in suites of correlated behaviors (animal personalities or behavioral syndromes). Most of earlier empirical knowledge comes from comparative approaches where long-isolated (>10,000 years / generations) populations facing different ecological conditions were studied. However, it is less clear whether behavioral divergence between isolated populations is possible on a much shorter time scale (decades). We study three-spined sticklebacks (Gasterosteus aculeatus), in river-based and land-locked populations in the North of the Netherlands. The extensive water management has led to a series of unintended "experiments" in the field, with populations of migratory sticklebacks being land-locked for different durations along the same river systems. Three-spined sticklebacks are ideally suited for investigating the causes and consequences of personalities in adaptation to novel environments. This is because they are widespread over a variety of habitats, with a plethora of morphological and behavioural variation, along with complex social and parental system, and there are many tools (genetics, genomics, transcriptomics) available for their study. Our findings suggest that, over only 50 generations, migratory stickleback populations were able to cope with forced residency and that the observed population differences likely reflect selection on personalities and morphology. Further experiments are underway to confirm the adaptive nature of the observed differences and unravel their underlying mechanisms (evolutionary change or plasticity). We will discuss these differences in the light of various mechanisms, competing hypotheses and investigate the plausibility and empirical relevance of these hypotheses on the basis of individual-based evolutionary simulations.
Supervisors: Sander van Doorn, Oscar Kuipers
Mutational influence on the evolution of resistance to the antimicrobial peptide nisin in Lactococcus lactis
Genetic variation is the second driver of evolution, next to natural selection and relies on mutations from replication errors. However, different mutation mechanisms create different genetic architectures in the individuals of populations, resulting in different foundations for following adaptation steps. Do these genetic differences also facilitate different adaptive pathways? To answer this question, we created mutator strains in Lactococcus lactis that depict either a higher point mutation rate or an additionally higher intrachromosomal cross-over rate. We compared these mutator strains to a non-mutator negative control strain in serial batch transfer experiments during seven weeks, by selecting for growth at progressively higher concentrations of the antimicrobial peptide NisinZ. The final, tolerated concentrations were on average lowest for the control strain and highest for the point mutator strain, with the hyperrecombinator strain tolerating slightly lower levels of NisinZ than the pure point mutator. The disadvantage of the control strain was also observed in lag phases and growth rates of the adapted strains at their respective concentrations. Earlier experiments revealed that the hyperrecombinator phenotype was toxic to the cells and lead to a higher mortality in the population. We conclude that higher mutation rates do grant an adaptive advantage when facing an ever increasing selection pressure, however that higher mortality reduces the speed of adaptation.
Supervisors: Rampal Etienne, Louis van der Zande, Martine Maan
Where I go is what I see?
Local adaptation to heterogeneous habitats can be a potent selective force in species divergence. One mechanism that may facilitate local adaptation is habitat choice. Making the choice of moving towards a new favourable habitat may initiate niche expansion and can, by exposing populations to new selective forces, ultimately lead to evolutionary change. To adequately assess habitats, organisms rely on sensory systems. Here, we aim to investigate the role of visual perception on habitat choice. Visual perception, a crucial determinant of fitness in many taxa (involved in i.e. foraging, mate choice), is mediated by photoreceptors, detecting different wavelengths of light depending on the absorption properties. Visual pigments are composed of an opsin protein covalently bound to a light-absorbing Vitamin-A-derived chromophore (i.e. either A1 or A2 derived). Recent work has identified the gene that produces the enzyme cyp27c1 responsible for converting A1 into A2. Expression of cyp27c1 are highly correlated with A2 proportion in the eye and red-shifted sensitivity. In this study, we investigate visual habitat matching in cichlid fish, which form one of the most species-rich families of vertebrates and widely recognized for studying as good model system for studying rapid adaptation to new environments. We aim to explore differences in habitat choice between species occupying different visual niches and align these differences to cyp27c1 expression.
Supervisors: Dick van Elsas, Theo Elzenga, Nataraja Karaba
Endophytic fungi-mediated abiotic stress tolerance in bittersweet
As a result of climate change, the abiotic stress factors such as drought, salinity, and flooding are predicted to increase in the coming decades. Plant adaptation mechanisms to these abiotic stresses are complex and controlled by polygenic traits. While understanding the adaptation mechanisms of plants to abiotic stress, plant associated microbes are often not being taken into consideration. Symbiotic association with endophytic fungi can provide fitness benefits to several crops. Endophytic fungi-mediated stress tolerance can be an alternative approach to develop abiotic stress tolerant crops. Though Solanum dulcamara has a wide ecological amplitude, ranging from wetlands to coastal dunes, the mechanisms behind its adaptation strategy is still a mystery. We hypothesize that S. dulcamara depends on their endophytic fungal community as an adaptation strategy to cope up with unfavorable environmental conditions. We use S. dulcamara, a wild relative of potato, thus as a model plant to unravel the potential stress tolerance derived from the host-symbiont relationship. We have isolated, identified and characterized endophytic fungi from S. dulcamara grown under contrasting habitats. We found that there is a huge variation in the composition of endophytic fungi across these habitats. These fungal endophytes were tested for their abiotic stress tolerance ability. By infecting sterile plants, the ability to impart stress tolerance in S. dulcamara will be tested. The potential candidate could be exploited to improve other solanaceous crops such as potato and tomato.
Natalie van Dis
Supervisors: Bregje Wertheim, Marcel Visser, Roelof Hut
Microevolution in action - Mechanism of adaptation to climate change in the winter moth
To assess the evolutionary potential of species to adapt to climate change, we need to gain insight into the underlying mechanism of adaptation to determine how selection can act on populations. The winter moth (Operophtera brumata) represents a unique opportunity to investigate the mechanism of microevolution to climate change in real-time. It is one of the few species shown to have genetically adapted to climate change and the only species for which yearly historical data and samples are available. In my PhD project, I aim to uncover the mechanism of genetic adaptation to climate change in the winter moth. I will determine the genes that are important in how winter moths respond to increased winter temperatures and map changes over time in the winter moth genome in response to climate change.
Supervisors: Rampal Etienne, Sander van Doorn, Michael Fontaine
The genomic architecture of adaptive speciation
Adaptive speciation is at the core of the emergence of biodiversity. By responding to natural selection, be it is through competition or local adaptation, and sexual selection, leading to reproductive isolation, species have evolved into the myriad forms we see today. While the ecological conditions favorable to adaptive speciation have been the object of extensive theoretical and empirical scrutiny, the conclusions derived so far often rely on restrictive assumptions regarding the genotype-phenotype map. Previous studies have assumed traits underlain by one or a few loci, or multiple loci contributing additively to the phenotype, whereas in nature quantitative traits are commonly underlain by gene regulatory networks offering ample opportunity for epistasis, i.e. gene-gene interactions, between hundreds of loci. Here, we explore the favorable conditions to speciation when the trait responsible for ecological adaptation is underlain by a gene regulatory network. Using agent-based simulations we compare the behavior of an adaptive speciation model with two ecological niches in a two-patch landscape under a polygenic genotype-phenotype map, with or without epistatic interactions between loci. We show that epistatic interactions relax the conditions under which adaptive speciation is expected. Because of a skewed distribution of mutational effects, epistasis increases the genetic variance in the population, which in turn facilitates the evolution of assortative mating. In contrast, additive traits rely on stronger disruptive selection to reach sufficient ecological variation for reproductive isolation to evolve. Our results highlight the importance of the interplay between the ecology and the genetics of species in the process of diversification.
Supervisors: Jean-Christophe Billeter, Bregje Wertheim, Rampal Etienne
Social modulation of egg-laying in Drosophila melanogaster
Being part of a group facilitates cooperation between group members, but may also lead to competition for shared resources if there are too many individuals. To solve this problem, individuals may modulate their behaviour and physiology according to group size and group composition. However, so far, we do not know what mechanisms can lead to such a social context-dependent modulation. In the fruit fly Drosophila melanogaster, females actively attract conspecifics to lay eggs communally by depositing aggregation pheromones on suitable sites. This increases the likelihood of survival and growth of the offspring through cooperation in fending off the growth of fungi competing for the same resources. Given the tractability of Drosophila, this system is a valuable tool for the elucidation of mechanisms that modulate behaviour in response to the social environment.
In this study, we show that Drosophila females start to lay eggs faster when in group than alone and that this egg-laying advancement is density-dependent. Investigation of the social parameters influencing egg-laying latency reveals that it is the mere presence of a group of Drosophila that triggers this behaviour in a focal female since it happens independently of the group member’s mating status, sex or species. This is explained mechanistically by our finding that females detect group size via the motion detection visual pathway – a pathway that does not allow for precise recognition of species and sex. We find that the presence of others affects egg-laying through hormonal stimulation of oocyte maturation and ovulation. We finally show that food and light interact with social context to modulate egg-laying latency indicating sensory integration of social and non-social cues. This study thus reveals extensive neuronal and hormonal mechanisms that modulate behaviour in response to the presence of others, shedding light on how individuals adapt to their social environment.
Sjoerd van Hasselt
Supervisors: Peter Meerlo, Theunis Piersma, Niels Rattenborg, Gert-Jan Mekenkamp, Alexei Vyssotski
The ecology of sleep - New insights on sleep homeostasis from EEG studies in barnacle geese
Sleep is considered to be of crucial importance for performance and health; yet, much of what we know about sleep is based on studies in a few mammalian model species under strictly controlled laboratory conditions. Data on sleep in different species under more natural conditions may yield new insights in the regulation and functions of sleep. We therefore performed a study with miniature EEG dataloggers in barnacle geese (Branta leucopsis) under semi-natural conditions, group-housed in a large outdoor aviary with natural temperature and light. A total of 16 geese were implanted with epidural electrodes to record brain activity (EEG) and neck muscle activity (EMG) using miniature dataloggers. Recordings were performed during winter and summer. Every recording had a minimal duration of 8 days which gave us detailed information on how sleep was affected by environmental factors. Sleep in the geese was highly variable across the seasons. During winter, sleep was mainly condensed during the night phase whereas during summer the animals became largely arrhythmic. Moreover, they slept 1.6 hours less in summer compared with winter. Seasonal variation in sleep time was best explained by photoperiod. Additionally, sleep was also affected by moon phase, with 3h less sleep during full moon compared with new moon. This study demonstrates that barnacle geese have high phenotypical flexibility in sleep under semi natural conditions and shows that environmental factors have a major impact on the organization of sleep and wakefulness.
Supervisors: Franjo Weissing, Ton Groothuis, Allert Bijleveld, Theunis Piersma
Causes and consequences of animal movement
All life exists and evolves in a spatial context. The ability to change that context through movement is thus an important aspect of the life-history strategy of individuals. I study the causes and consequences of animal movement at two different scales and using different methods. At the evolutionary scale, I use individual based simulations with thousands of agents to examine how movement strategies evolve on fluctuating environments, and how adaptable these strategies are in a time of environmental change. At the ecological scale and in collaboration with NIOZ, I use high resolution tracking data from the Wadden Sea ATLAS system to study how wintering red knots (Calidris canutus) move over the coastal mudflats of the Wadden Sea, whether they show individual consistency, and the consequences of their movement strategies. Here, I present a brief overview of my work in these fields.
Supervisors: Allert Bijleveld, Theunis Piersma, Ton Groothuis, Franjo Weissing
Across context consistency in individual movement behaviour of red knots (Calidris canutus)
Movement ecology investigates the internal and external factors that affect movement. One of the internal factors is the individual differences. Consistent individual differences, also known as animal personalities, are now seen as one of the possible causes that affect movement. There are not many empirical studies merging personality research and movement ecology. The key limitation for that is that it relies on the assumption that behaviour in a captivity correlates with natural behaviours expressed in the field. Here we aim to scale-up from movements in the experimental laboratory settings to large-scale movements in a natural setting to study personality dependent movement in the wild populations. In captivity, red knots have been shown to differ consistently in their exploratory behaviour. In this study, we investigate whether individual differences in exploratory behaviour link to differences in their movement in the wild, the Dutch Wadden Sea. We first present a field method to quantify exploratory behaviour within 1-3 days after catching. Using time-of-arrival method, we then tracked the foraging movements of 137 red knots over a series of low tide periods to quantify individual movement patterns in the wild. We found that exploration personality predicts space use in the wild; exploratory birds visit more patches for shorter time periods, and travel more during low tide. Our results show that even in the big flock of birds, movement is linked to individual, rather than environmental mechanisms and it is important to take personality into account to understand movement and spatial distributions in the wild.
Supervisors: Simon Verhulst, Ido Pen, Irene Tieleman
Mosaic ageing of the immune system in zebra finches
That every organism ages and eventually dies is a universal trait of life. The rate of aging is however not the same for every organism. Recent research into the dynamics of various bodily traits has shown that there is a remarkable diversity in their rate of decline with age, ranging from stasis to gradual decrease in various different combinations. This phenomenon is known as mosaic aging.
The immune system is one of the most complex physiological systems, and has a high diversity of different components that are being studied. This complex system is ideal for studying mosaic aging patterns, since decline of the various immune components is not always synchronous and can be influenced by environmental factors.
Together with models, we use an experimental approach where we study mosaic aging of the immune system in zebra finches. We use different combinations of three manipulations in external condition, which we know affect lifespan. This enables us to dive into the dynamics of, and conditions required for, synchronous or mosaic ageing, and will give insight into the importance of various immune components, based on the investment into maintaining them throughout life
Supervisors: Simon Verhulst, Sietse de Boer
The developmental plasticity of personality traits in zebra finches
While the ecological and evolutionary consequences of consistent variation in behaviour, or personality, are well studied, the causes of this variation remain poorly understood. Part of the variation in such personality traits can be attributed to genetics, with reported heritability rates of up to 50%. Nevertheless, these traits show substantial phenotypic plasticity and can be profoundly affected by environmental conditions. Here, it is often suggested that environmental conditions experienced during early life, during development, can have life-lasting consequences on the way an individual behaves. This process is termed developmental plasticity.
Within my research project, I investigate the effect of an early developmental environment manipulation on adult personality traits in the zebra finch. Furthermore, I aim to investigate the mechanisms underlying the behavioural expressions of personality. These mechanisms are (1) the metabolic machinery of an individual, and (2) the expression of selective neuromolecular mechanisms, including oxytocin, dopamine & serotonin.
Venue: Hanze Plaza, Protonstraat 16, 9743 AL Groningen
24 June: GELIFES's 5th Anniversary
Five years ago the merger of two the former institutes CEES and CBN into the new Groningen Institute for Evolutionary Life Sciences was officially finalized with a symposium on the integrative theme of the new institute. This year we will celebrate our first GELIFES lustrum with another symposium presenting the results from both exciting new collaborations, and tried and trusted partnerships of yore.
|Last modified:||12 March 2020 3.21 p.m.|