Browsing by study line "no specialization"
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(2020)Early life conditions have long-term effects on the fitness and survival of individuals. Foetal development is an especially crucial period and even small changes may have large impacts on the development of individuals. Mammal foetuses may be exposed to additional testosterone either from their male littermates or their mother. This additional prenatal androgen exposure leads to masculinization of female features and behavior. In males the effects of additional prenatal androgen exposure are less drastic due to their own testosterone production. The anogenital distance, defined as the distance between the anus and genitalia, has been used to determine the sex of young mammals since males have longer anogenital distances than females. An elongated anogenital distance is an indicator of additional prenatal androgen exposure in females, and in some species also in males. It correlates with for example increased aggressiveness in both females and males. In females a longer anogenital distance has also been connected to delayed puberty and decreased fertility. I studied the effects of additional prenatal androgen exposure on weight and important life-history traits in banded mongooses (Mungos mungo) with data from a long-term study. Banded mongooses are small co-operatively breeding mammals living in family groups of 10-30 individuals across sub-Saharan Africa. Breeding is extremely synchronized within groups and in most cases all pregnant females give birth on the same day. The resulting communal litter is cared for by most adults in the group regardless of relatedness. Adults escort the pups until three months of age, providing the pup with food, grooming and protection. This early life care has long-term fitness benefits for the pups. Pregnant females may change the phenotype of their offspring via maternal effects. When the competition faced by breeding females is more intense, they compensate by investing more resources to their foetuses, making them bigger. Using the anogenital distance as a proxy for additional prenatal androgen exposure, I measured its effects on weight at early life and maturity, the amount of care received as pups and whether the individual reproduced in its lifetime or not. I hypothesized that a longer anogenital distance may be an indicator of increased competitiveness in the banded mongoose. It could lead to a cumulative advantage since more aggressive individuals may be able to access more food and care, which leads to higher maturity weight and lifetime reproductive success. I also measured the effects of resource abundance and intensity of competition during gestation on the anogenital distance of the pups. I hypothesized that mothers may prepare their offspring for future competitive environment by exposing them to androgens during gestation. In males a longer anogenital distance predicted higher weight both at early life and maturity. Higher weight at the beginning of the escorting increased the amount of care received, which in turn increased weight at maturity. A longer anogenital distance therefore has both direct and indirect fitness benefits in male banded mongooses. In females, a longer anogenital distance predicted lighter weight at maturity, suggesting that it may have negative effects on female growth and development. This study offers evidence that additional prenatal androgen exposure has long-term fitness consequences on banded mongooses and that these consequences are sex specific. Future research should focus on confirming the connection between additional prenatal androgen exposure and longer anogenital distance in this species, as well as assessing the effects of prenatal androgen exposure on survival, puberty and growth of especially female individuals.
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(2024)Työssä kuvataan eri puolilta Suomea toukokuussa 1976 eläinsuojista kerättyjen talvehtineiden hibernaatiossa olleiden naaraiden insektaariossa munimien munien morfologiaa. Valomikroskoopilla munista määritettiin yläpinnan kirjailu, mitattiin munan kokonaispituus, yläpinnan leveys,kellukkeiden pituus sekä laskettiin kellukkeiden kaarien määrä. Munan yläpinnan kirjailuun ja yläpinnan leveyden - munan kokonaispituuden väliseen suhteeseen perustuvien määritysten avulla aineistosta oli todettavissa kaksi lajia: Anopheles messeae messeae Falleroni sekä Anopheles beklemishevi beklemishevi Stegnii & Kabanova. A. b. beklemishevi määritetään Suomesta ensimmäistä kertaa. SEM- ja TEM-kuvauksissa tutkitaan Hintonin (1968) mainitsemia piirteitä, joiden hän katsoo eroavan eri Anopheles lajeilla. Lajinmäärityksen kannalta SEM-tarkastelu ei ole tarpeellinen, sillä mainittavia eroja ei löytynyt kuin yläpintaa ympäröivän reunuksen ja kellukkeiden liittymäkohdasta. Lisäksi työssä esitetään em. lajien levinneisyys ja vertaillaan saatuja levinneisyyskarttoja vanhoihin malarian levinneisyyttä Suomessa ja muualla Pohjoismaissa käsitteleviin tietoihin.
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(2021)Biodiversity is decreasing globally due to human activity. At times, on-time monitoring of the state of habitats and biodiversity is challenging. One useful way to study these is to use certain species as indicators for the state of habitats and biodiversity. One group that are often used, are birds. They are easy to detect and they have specialized to most terrestrial ecosystems. Changes in the population sizes of different bird species can reflect changes in different habitats and their biodiversity. Therefore, it is essential that different bird monitoring practices produce reliable and comparable results. I compared datasets produced by two different Finnish bird census programs in my thesis. The census programs were national breeding bird survey program and Hanko Bird Observatory´s migratory bird census program. Both programs produce data on population abundances and changes in population sizes. Because methods between these programs differ greatly, their data may differ for some species. I compared the datasets by comparing population change indexes of the same species. I also tested whether species traits would be associated with the comparability of the datasets. These traits were mean body size, migratory behavior, favored habitats, and number of sightings for each species. I made models for all combinations of traits. I used a generalized linear model in my analysis. I compared the models by using Akaike´s information criterion (AIC) with correction for small sample sizes (AICc). My results showed that both national breeding bird survey program and Hanko Bird Observatory´s migratory bird census program produce parallel population trends for species. From the tested species traits, only migratory behavior was associated with comparability of the datasets. The datasets were highly comparable for long- and short-distance migratory birds but only moderately comparable for resident birds. This is likely due to migratory bird census program recording the local population dynamics of resident birds of Hanko peninsula. These local population trends may differ from the national trends of the same species. The breeding bird survey program should better reflect the national population trends. My results also showed that more numerous common bird species are declining faster than uncommon species. This is an alarming scenario because it points at extensive habitat degradation and biodiversity loss. Also, population trends of species favoring mires and mountains were clearly declining compared to species favoring other environments. This may be due to endangering of mire and mountain habitats due to climate change and human land use such as peatland drainage. Strong declines of species may also be explained by changes in the wintering areas of these species. Finnish breeding bird survey program and Hanko Bird Observatory´s migratory bird census program both produce overall comparable data on population trends of birds. They could be used to complement one another and to provide supporting evidence on the validity of bird population trends. Producing quality bird census data is highly important in tracking the state of biodiversity and when deciding on conservation acts. The data on the census programs provide support for the research on state of Finnish and European habitats and biodiversity.
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(2020)Conservation actions towards large carnivores have been successful in Europe, and the formerly lawfully persecuted species have started to reclaim their historical range. Coexistence with the predators is needed if their conservation should continue to succeed, as Europe does not host wilderness areas large enough to separate large carnivores from humans. As the importance of top-down regulation in ecosystems is recognized, the protection of these predators becomes essential. In Finland, all four large carnivore species, brown bear, grey wolf, Eurasian lynx and wolverine, have established populations, though their presence is not easily accepted by some. Large carnivores pose a threat to livestock and cause fear in the locals living in their territories. Wolf – hunting dog conflict is especially prominent in Finland south of reindeer husbandry area and the poaching of wolves hinders the population’s management. Attitudes towards large carnivores are often influenced by personal background, such as education level, ecological knowledge and respondent’s position in possible human – wildlife conflict. Residence can have an effect, as well, since conditions between living in urban or rural areas often differ. Hypothesis for this study are 1) attitudes towards large carnivores get worse while getting closer to protected areas, 2) attitudes towards large carnivores differ between eastern and western study areas, and 3) a higher education level increases positive attitudes towards large carnivores. The effect of ecological knowledge, prior experiences with large carnivores, age, sex and position in conflict was also explored. Study was conducted as a questionnaire, with face-to-face interviews and web survey distribution targeting two areas in Finland with large carnivore occupancy, one in the West and one in the East. A link between negatively perceived personal experiences and negative opinions towards large carnivores and their management was found. Living in the western area, where large carnivores have resided for a shorter time, predicted attitudes towards stricter management of the species. Third level education influenced attitudes positively. By understanding local attitudes towards large carnivores, it is possible to better understand the conflict between humans and predators, and so, find more likely solutions. Conservation actions where locals have been included, have been documented as successes. Regional differences in attitudes should be further studied and included in future decision making.
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(2023)Three-dimensional (3D) cellular cultures have been shown to represent tissue formations and functions more accurately than two-dimensional (2D) cultures and have been successfully utilized more accurately in model organisms, e.g., to understand cellular modular functions. However, the applications in non-model organisms are limited, and to our knowledge have not been implemented in ectotherms. At an ecological scale, the technique can enhance our understanding by providing insights on cellular and tissue level molecular mechanisms. A potential implementation of this method in Atlantic salmon is to elucidate the molecular function of the vestigial-like 3 (vgll3) gene, which plays a central role in salmonid maturity, potentially by regulating energy allocation via regulating adipogenesis. In this thesis, a proof of principle study was implemented, where the feasibility of obtaining and maintaining a suspension 3D adipose tissue culture in Atlantic salmon (Salmo salar) was assessed. The harvested visceral white adipose tissue from around the intestinal tissue of mature Atlantic salmon (salmon past smolt stage) was first separated into stromal vascular fraction (SVFs) and mature adipose fraction (MAFs). SVFs contain preadipocytes (precursors of adipocyte cells) in addition to a variety of other cell types. MAFs are mature adipocytes. Both MAFs and SVFs were successfully maintained in-vitro for over four weeks. SVFs were then successfully differentiated into mature adipocytes, demonstrating the feasibility of studying adipogenesis in Atlantic salmon. Proof of this methodology and its further implications may help us to understand the cellular functions of vgll3 and may subsequently help to better understand its causal relation to the maturation process in Atlantic salmon.
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(2024)Korkeasaari Zoo has several large ruminants adapted to distinct climates and habitats. It is well known, that ensuring the possibility of the animals to live in captivity, that resemble their natural habitat, is important for their welfare. However, thermal environment of zoo-housed animals is not often studied, even though it can have major impact on animal welfare. Especially for cold-adapted species the shade availability during hot, sunny days is essential and therefore needs high attention. In my thesis, I monitored the shade use and behaviour of musk ox (Ovibos moschatus), yak (Bos grunniens), takin (Budorcas taxicolor), wisent (Bison bonasus), Przewalski’s wild horse (Equus przewalskii) and kulan (Equus hemionus kulan) in their enclosures in Korkeasaari zoo by using ZooMonitor application. Species were chosen by their different level of warm adaption for comparison. I found out the shade availability in each enclosure during different times of the day with aerial photographs. The purpose was to find out if there is a need to enhance the shaded areas to ensure animal welfare. Research questions were 1) How much shade is available in each enclosure? 2) Is shade use dependent on a) temperature b) time of the day? 3) Are less warm adapted species (musk ox, yak, takin) seeking shade more obviously than more warm adapted species (wisent, kulan, wild horse)? To analyse, behavioural space use data was assessed in the form of a heat map with aerial photographs to evaluate location preferences for each animal in each enclosure. Behaviour Budget reports were used to display the percent of time engaged in behaviours. In conclusion, musk ox has shade in their enclosure 43% in the morning, 18% in the noon and 36% in the afternoon. Its shade use is dependent on time. Yak, kulan and wild horse has shade 33% in the morning, 18% in the noon and 21% in the afternoon. Shade use of yak and kulan is dependent on temperature. Shade use of wild horse is dependent on time. Takin has shade 93% in the morning, 73% in the noon and 77% in the afternoon. Its shade use is dependent on temperature and time. Wisent has shade 57% in the morning, 43% in the noon and 14% in the afternoon. Its shade use is dependent on time. Less warm adapted species are seeking shade more frequently than more warm adapted species, but surprisingly kulan stronger than wisent and almost equally as yak. Combined, shaded areas are important for zoo-housed animals to thermoregulate. The least warm adapted musk ox needs more shaded areas as they are scarce in their enclosure. Providing more shaded areas increases the space available for the animals.
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(2020)The Miocene epoch (c. 23-5 million years ago) was a noteworthy geological time period in which significant changes took place both in the climate regimes as well as in vegetation characteristics, bringing about novel adaptations in many herbivorous lineages. These adaptations constituted morphological, dietary, and ecological factors in a relatively short period of evolutionary time. Among these herbivores were the proboscideans, the living and extinct elephants, which were among the most dominant and largest herbivores at the time. Despite that proboscideans were diverse and large group of hundreds of species, yet the understanding of dietary and ecological patterns of majority of Miocene sympatric species is still limited. The aim of this study was to analyse the molar surfaces of Miocene proboscideans (e.g. Deinotherium and Gomphotherium) from Eurasia to provide a reconstruction of the feeding preferences of the study species based on observed dental wear. The dental wear indicates the abrasiveness of the diet, thus allowing broad categorization to either browser (<10% grass in the diet), mixed-feeder (10-90% grass in the diet) or grazer (>90% grass in the diet). Secondly, this study aimed for providing estimation of the environmental characteristic and vegetation patterns of the study localities by comparing to the previous studies and to hypsodonty value (proxy of general openness and aridity of the environment). Proboscidean dietary signals from the key localities of Maragheh (Iran) and Pannonian basin (Austria) were compared with the paleobotanical studies. Thus, the general estimation of spatial and temporal variation of the environment characteristics in the study localities were based on these parameters. The materials of fossilized molars were analysed by mesowear angle method, in which the measured angles show the diet abrasiveness due the nutritional targets’ differences. The results allowed the reconstruction of the feeding preferences which suggested that majority of Miocene proboscideans were browsers and browse-dominated mixed feeders or pure mixed-feeders. Instead, Choerolophodon pentelici was found grass-dominant mixed-feeder. The wide spectrum of feeding preferences allowed diet flexibility according available vegetation and also these sympatric species to co-exist by niche partitioning. Thus, demonstrating clearly the connection between diets and environments thought the diet. As a conclusion, in the diet of the paleocommunities of proboscideans had, on average, more grass-dominant components in open and dry environment likely due the presence of grass-dominant vegetation. Instead, in the wet conditions the closed-canopy forest environments enhanced browsing. Further, the results indicated shift in feeding preferences of proboscideans prior to Miocene climate and environment changes. These results are in line with the findings of the previous studies of modern elephants’ diet- environment relationships. The further studies would provide insight to the relative amounts of the grass in the diet of Miocene proboscideans.
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(2020)As biodiversity is being lost worldwide at an accelerating rate due to anthropogenic activities, the frequency and severity of many infectious diseases has been observed to increase. Together these patterns have brought forth an urgent need to understand the possible linkages between biodiversity and disease risk. Two contradicting hypotheses have been proposed to explain the diversity-disease relationship. The dilution effect hypothesis suggests that increasing host community species diversity ‘dilutes’ disease risk, whereas the amplification effect hypothesis predicts disease risk to increase with increasing diversity. Even though most of the studies support the dilution effect, there remains an intensive debate regarding the generality of this effect. As most of the research efforts to understand the relationship between diversity and disease have focused on animals and crop plants or have been carried out experimentally, one of the research gaps is how relevant the dilution effect is in wild plant communities. In nature, plants and their diseases are affected simultaneously by multiple abiotic and biotic environmental factors that might confound or supersede the effects of diversity. It is also poorly understood, whether we might expect dilution effects to occur not only on diversity gradients driven by anthropogenic diversity loss, but also on natural diversity gradients. To study the possible association between host community species diversity and disease risk in the wild and to test whether this association could be detected after accounting for the effects of abiotic factors, I surveyed grassland vascular plant communities for their species diversity and foliar disease symptoms along a natural diversity gradient driven by elevation. I also recorded data on the mean soil surface temperature in the surveyed plant communities and used structural equation modelling to differentiate and compare the effects of biotic and abiotic variables on disease risk. The data were collected on Mount Calanda in the Swiss Alps during summer 2019. In this thesis I show that host community species diversity and disease risk are negatively associated with each other along a natural diversity gradient driven by elevation. Furthermore, this negative effect can be detected even after accounting for the effects of elevation and mean soil surface temperature on disease. Together the results support the occurrence and the ecological relevance of the dilution effect in wild plant communities along natural diversity gradients and suggest that diversity might protect wild plant communities from increased disease risk. Future studies should aim to identify the exact mechanisms of the association to help us better understand when and where we might expect dilution effects to occur in the wild. This knowledge can be used to predict how epidemics, that affect the well-being of ecosystems, humans and wildlife, are born in the changing world.
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(2024)Dispersal is a vital life-history trait in terms of species survival, reproduction, and persistence, among others. We know that temporal and spatial differences in the environment alter the risks and rewards involved in dispersal, thus influencing dispersal behaviour and ability. Less known, however, is how exactly seasonal shifts and land use together affect dispersal ability. Butterflies are a well-known and ecologically important study group whose traits are majorly influenced by environmental conditions. Here, I study how the dispersal ability of the green veined white butterfly (Pieris napi) is influenced by when they fly, as well as land use in their local habitat. I collected butterflies of two subsequent generations during the late spring and summer of 2023 in the Åland archipelago (Finland). I then measured the flight metabolic rates and forewing lengths of these butterflies to estimate their dispersal ability. The results described here indicate that P. napi females flying in late spring and early summer are more capable of dispersing than those flying later in the summer. Land use had seemingly no effect on P. napi dispersal ability. Identifying the factors that influence dispersal is key in understanding and securing the future for species in a changing world.
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(2023)Macrozooplankton is an understudied size class of plankton in the Arctic, but even though species composition is similar around the Svalbard archipelago, the relative composition can act as a proxy for climate change. This study investigated if the fjords around Svalbard are similar in species composition and if any differences could be explained. 11 fjords were sampled with a focus on common and indicator species in terms of abundance, relative composition and length distribution. I found low presence of T.libellula and high abundances of T.abyssorum and T.inermis. T.abyssorum was the only species whos abundance was significantly correlated to water mass (Atlantic water), but T.libellula, T.abyssorum, T.inermis, T.longicaudata and A.digitale all showed significant differences in length distribution. This study provides further understanding of species composition in the different high Arctic fjords around Svalbard.
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(2024)Climate change and overexploitation are an increasing threat in marine ecosystems as human activities have risen over the past decades. One of the main tools for protecting biodiversity and ecosystem functions is the designation and implementation of Marine Protected Areas (MPAs). Despite their potential for conservation, recent assessments question the effectiveness of MPAs to conserve ecologically resilient ecosystems. In this thesis, I aim to assess the effectiveness of MPAs in Finland using long-term phytoplankton data, which have been collected for almost 60 years (1960-2020) in the Finnish territorial waters from over 700 sites and contain 991 different phytoplankton taxa. Phytoplankton is the basis of marine food networks and thus shifts in phytoplankton communities can affect higher trophic levels. I compared the total biomass, species richness and species diversity of the phytoplankton communities between protected and unprotected sites. To control for the confounding effects of environmental variables that affect phytoplankton biomass and distribution, and to isolate the effect of protection, I employed nonparametric distance matching; essentially, this process selects comparable pairs of samples from protected and unprotected sites. I found that even though there was a general increase in species diversity with time, protection had no effect on phytoplankton biomass, species richness or species diversity. The size and age of the MPAs did not affect the protection outcomes. However, strictly protected MPAs harbored lower biomass compared to unprotected sites, which could indicate that MPAs can help reduce the effects of eutrophication. These results suggest that MPAs in Finland still have room to be improved and there is a need to accurately assess their effectiveness in order to successfully safeguard biodiversity. Considering the phytoplankton component during the designation and planning of the MPA network in Finland could be valuable for marine conservation.
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(2021)Post-transcriptional modifications (PTMs) in RNA are present in all known RNA species and conserved in all kingdoms of life. Transfer RNA (tRNA) has been shown to have numerous conserved modifications, which exemplifies the importance of modifications having impact on the structure of the tRNA and its function as carrier of the amino acids. Ribosomal RNAs (rRNA) are universally modified as well, and modifications are situated at functionally important spots of the ribosome. Given the fact that types and sites of modifications are conserved, it is likely that these modifications have been selected for and that they optimize the ribosomal structure and functions. Stress, such as temperature or infection by a pathogen, is known to change the presence or abundance of modifications in RNA molecules and thereby affect translation efficacy. In line with that, this master’s thesis project sought to gain insight into the dynamics of PTMs in tRNA and rRNA upon oxidative stress, with the goal of utilizing recently optimized UPLC/MS method for identifying modified ribonucleosides. As the specific aim of the thesis was to estimate the change in PTMs in tRNA and rRNA in response to oxidative stress with 0.5 mM and 2 mM hydrogen peroxide H2O2, 3 immediate goals were: (i) to isolate total tRNA from yeast grown in stress conditions, (ii) to isolate rRNA from yeast 80S ribosomes, and (iii) to identify present modifications using mass spectrometry. Yeast was cultured in presence of H2O2 as a stressor in mentioned concentrations, and both treatments considered showed a difference in survival when compared to the control. Rough cell concentration estimates (OD600) did not show the effect of the stressor on cell survival clearly, but when number of viable cells per mL was estimated, it was clear that growth of the stressed yeast cultures was hindered 2 hours after exposure to H2O2 but recovered during the 24 hours. Firstly, using UPLC/MS analysis, 29 modifications were identified in tRNA from control and H2O2 treated yeast. Most identified modifications showed no change in abundance in treatments, which is to be verified with additional replicates. However, distinct dynamics of stress-related change was found for several modifications, revealing additional modifications that may play a role in stress related modificome reprogramming to the previously known signature modifications of oxidative stress. It was expected that recovery of culture growth after 24 hours may be accompanied with modification level recovery. However, that was not demonstrated here as downregulation at 2 hours followed by upregulation at 24 hours was seen for 2-methylthio-N6-methyladenosine, N4-acetylcytidine and 5-methoxycarbonylmethyl-2-thiouridine, and the reverse was shown for N4-methylcytidine. Upregulation in both time points was also shown here for some modifications. Taken together, these results confirm a complex and dynamic control of tRNA modifications in cellular survival responses. Modifications found to be affected by oxidative stress are most frequently located on the wobble position 34 and anticodon loop position 37, so it is expected that changes in their modification levels could directly affect the tRNA function in translation, making them a specific target for future research. Secondly, modifications in rRNA from control yeast cultures were identified, such as expected methylations of all 4 canonical nucleosides. However, further analysis will be needed to confirm the other identified modifications, due to the potential mRNA and tRNA contamination. Optimizing the method for rRNA modifications identifications by acquiring more modified nucleosides specific for the rRNA to use as standards in the analysis, analyzing rRNA types separately and using tandem mass spectrometry would enable getting a deeper understanding of which modifications are present and where they are positioned. Finally, it would enable reliable identification of the signals of novel modifications present in rRNA, such as the tRNA modification 5-carbamoylmethyluridine signal found here. In conclusion, this thesis work lays the foundation to study the evolutionary conserved function of PTM changes during stress as modulators of translation, using the methodological approaches discussed in-depth within the thesis, primarily to confirm the intriguing results found here.
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(2020)Behaviour is a key component in ecological interactions and studying its role in adaptation is central in our understanding of natural selection and phenotypic variation in the wild. Predation is an important driver shaping animal behaviour in the wild, since predators have been shown to select against particular behavioural phenotypes. However, it is not easy to demonstrate that specific behaviours are adaptive to certain levels of predation, since behaviours are often correlated with each other forming multivariate phenotypes and display notable phenotypic plasticity. I studied how predation shapes genetically determined behaviour of the nine-spined stickleback (Pungitius pungitius) through variation in historical predation pressures and by inducing phenotypic plasticity. This was achieved through rearing 65 full-sib families of nine-spined sticklebacks derived from four coastal marine (predator-sympatric) and four pond (predator-naïve) populations in a common garden experiment and quantifying their behaviour in the laboratory in the presence and absence of natural predators. Since the fish used were F1-generation offspring from artificial crosses, I was also able to estimate the heritability and genetic correlations of the studied behaviours. Pond sticklebacks tended to be more explorative and took more risks during foraging than marine sticklebacks regardless of predation risk. In all fish, predator presence decreased the propensity to take risks during foraging, but not exploration tendency. Since the fish were reared in a common garden setting, there is a genetic basis for these population differences. Both behaviours were heritable in all populations. In this study, I observed genetically based and heritable behavioural differences between pond and marine stickleback populations. Despite showing similar levels of behavioural plasticity as marine sticklebacks, pond sticklebacks were still inappropriately active in the presence of predators and would have a low survival probability in a predator-sympatric environment. In risk-taking during foraging, the behavioural trend caused by acute predation risk was directionally the same as that caused by evolutionary history of predation risk, implying that the behavioural differentiation between marine and pond populations in this behaviour is due to predation. These results provide evidence of local adaptation in behaviour to differing levels of predation in these populations, and that this adaptation comes about as differences in the overall level of behaviour rather than in phenotypic plasticity.
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(2022)Woodland strawberry (Fragaria vesca) is a perennial herb in the Rosaceae family with dimorphic leaves, summer and winter leaves, adapted to seasonal climate. Woodland strawberry produces a new set of leaves in spring that are photosynthetically active throughout the summer season (summer leaves), and the leaves senescence in autumn when they are replaced by a new set of leaves (winter leaves). The winter leaves retain photosynthetic capacity under the snow cover throughout the winter season, which prolong the photosynthetic period of the species. With the world-wide climate warming, the thickness of winter snow is decreasing, which can affect overwintering and spring phenology of plants. This thesis focuses on springtime ecophysiology and phenology of the senescing winter leaves and the formation of new summer leaves of woodland strawberry genotypes of different European origin. The 15 different genotypes of woodland strawberry are from Iceland, Italy and Norway, and they originate from different environments that are geographically separated from each other, so the populations are genetically distinct. In this study, these genotypes were kept at two different overwintering sites, coastal site at the Åland islands with mild temperatures, and continental site in Lammi with a persistent snow cover. According to the results all 15 genotypes showed earlier development of the summer leaves and earlier senescence of winter leaves in the group with Åland as overwintering site than in the group with Lammi. Another important finding is that the first summer leaves produced in spring begun to senesce shortly after they are fully developed and were replaced by later formed summer leaves. Specifically, the dates of summer leaf formation, flowering and stolon production were advanced, and the dates of winter leaf senescence were also advanced. The value of different leaf types to chlorophyll fluorescence was also lower at the Åland site. Therefore, it can be concluded that overwintering conditions have an effect on the subsequent phenological development in spring. In the context of global climate change, the spring development of woodland strawberry will be earlier, and the senescence of winter leaves will also be earlier.
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(2021)Rapid environmental changes over the last 100 years have led to substantial range shifts across taxonomic groups. Understanding what facilitates successful shifts is important for predicting ecological consequences and planning efficient conservation actions. Interestingly, the very process of range expansion can affect the success of the shift by causing genetic changes in the expanding populations. Theory predicts that without sufficient gene flow, repeated founder events and strong genetic drift can result in allele frequency gradients and loss of genetic diversity along the expansion axis. Empirical studies testing these expectations in environment-driven range shifts are still relatively scarce, and how range expansions affect genetics in highly mobile species remains unclear. In this study, I investigated the genetic consequences of a recent range expansion in a long-distance migratory passerine, the reed warbler (Acrocephalus scirpaceus). Utilizing genome-wide data from restriction site-associated DNA sequencing (RAD-seq), I studied whether the expansion was reflected in either population structure or genetic diversity of the recently established Finnish range edge population. Despite philopatry and genetic differentiation to the range core populations, principal component analysis (PCA) and a model-based Bayesian clustering approach (fineRADstructure) revealed a lack of spatial population structure along a putative colonization route. Levels of genetic diversity, based on expected heterozygosity, nucleotide diversity, and private allele count, were found to be very similar between range edge (Finland) and range core (Central Europe). The results likely indicate high levels of gene flow both within the new population and across greater spatial distances during or after the range expansion. Due to a detected sequencing batch effect, however, the exact diversity estimates must be considered preliminary. These findings suggest that species with high enough dispersal propensity may escape the predicted genetic costs of range expansions, retaining high levels of genetic variation at range margins. This study provides valuable insights for understanding range shifts in mobile taxa, and highlights the need to investigate further the traits of species that enable the preservation of evolutionary potential during range shifts.
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(2018)As a genome editing tool, CRISPR-Cas9 has provided a robust way to generate mutations in the gene of interest, at a certain time point, and in selected cell populations. The impairment of dopaminergic neurons in the substantia nigra is addressed to be one of the main pathologies of Parkinson’s disease. The histopathology of Lewy Bodies, with an undetermined role, accompanies the demise of DA neurons. Development of strategies for the prevention the neurodegeneration has a potential to slow down the progression of Parkinson’s disease. In this study, a novel, neuron-specific CRISPR-Cas9 system was developed for the purpose of dissecting neuroprotective pathways in primary dopaminergic neurons. The optimization of the tool was done by targeting EGFP at TH-positive neurons obtained from transgenic animals expressing EGFP in dopaminergic neurons. Complete loss of EGFP was achieved at day 6 after the introduction of the CRISPR-Cas9 via lentiviral vectors. There were no survival or transduction efficiency differences. Two significant pathways for the survival of dopaminergic neurons, the microRNA biogenesis and GDNF/RET signaling were selected to collect the preliminary data. Dicer, Trbp, Translin, Ago-2 and Ret were targeted with single sgRNAs, which were specifically designed to create indel mutations in these genes, and specific lentivirus vectors were produced with each guide. After transduction with the lentivirus vectors, survival of the TH-positive neurons was unaffected. Data obtained from the quantitative PCR suggested that there was 50-70% decline in transcript levels of Trbp. However, the unchanged transcript levels of the other miRNA-related targets suggest the need for further optimization of the specific guides. Knockdown of Ret was validated by inhibition of pharmacological benefits of GDNF. Overall, this research has shown the further development of this CRISPR-Cas9 tool would be useful to dissect neuroprotective signaling pathways in dopaminergic neurons.
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(2024)Secondary growth in plant vasculature tissues originate from meristematic tissue vascular cambium. Vascular cambium produces xylem inwards and phloem outwards in the plant root and stem. Vascular cambium regulatory mechanisms are not completely known, and while plants and especially trees are dependent on the mechanical support and transportation systems the vasculature provide, increased knowledge of the vascular cambium and especially xylem development is valuable. In this thesis, I explored Arabidopsis thaliana single-cell RNA-sequencing data from secondary growth stage via cloning transcriptional reporter lines, and later utilized the transcriptomics data to find potential xylem development regulators. By loss-of-function mutant and inducible overexpression line screening, I found two genes in a family of MYB transcription factors to be potential regulators in xylem development. Loss-of-function mutant did not show significant phenotype, but overexpression lines under constitutive 35S promoter showed extreme halt of growth, and a stain-filled vessel phenotype in a fixed and resin-embedded Arabidopsis cross-section. Under developing xylem -specific promoters, inducible overexpression lines showed the same phenotype, and while grown to the secondary growth stage, I detected some patterning defects. Thus, these results indicate, that these MYBs expressed in the xylem parenchyma in the single-cell transcriptomics data, might have a function in xylem development.
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(2018)Life historyresearch seeks to explain how natural selection and ecological challenges shape organisms to optimize their fitness. A strong immune defense is energetically demanding to upkeep and there may be trade-offs among other life history traits. Investing a lot of energy to upkeep a strong immune defense in conditions where there are less pathogens and parasites might have negative fitness effects. Heliconius eratois a neotropical species of butterfly found widely in South America. The immune defense, ecologicalfactors affecting its immune defense, and possible life history trade-offs of the butterfly are currently not well known. Environmental moisture conditions have been shown to affect the diversity, quality and amount of microorganisms and parasites. The aim of this thesis was to use real-time quantitative PCR (RT-qPCR) to quantify immune gene expression of individuals of the butterfly species Heliconius eratocollected from different environmental moisture conditions. Additionally, individual variation in encapsulation rates, a physiological measure of immunity, was compared across the moisture gradient. Results indicate reduced expression of the gene encoding the antimicrobial peptide attacin in dry conditions, but no difference in encapsulation rates across the moisture gradient. Additionally, differential expression of the prophenoloxidase encoding gene was found between male and female butterflies. These results indicate a possibility of differential immune threats in different environmental moisture conditions in H. erato, but requires further study.
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(2021)In the process of decomposition soil carbon is transformed into CO2 by microbial respiration, which makes decomposition a key process for understanding carbon cycling an releases of CO2. Since the northern permafrost regions contain half of all belowground carbon and the tundra regions are expected to be markedly affected by climate warming, it is of particular interest to understand how warming will affect decomposition in the tundra. Decomposition is however influenced by many factors, from climatic factors such as temperature and precipitation to the belowground organisms inhabiting the soils and the aboveground system dictating the litter that falls to the ground and is decomposed. Further, grazing has been shown to oppose some of the effects of warming on tundra. In this thesis I analyzed data collected from two long-term field experiments, one in Kilpisjärvi (NW Finland) and the other close to Kangerlussuaq Fjord (SW Greenland), both using fencing for manipulation of grazing regime and open-top chambers for artificial warming. My aim was to not only investigate how warming and grazing affect decomposition, but also to understand whether the magnitude of changes in decomposition can be explained by changes in plant community traits and soil characteristics. I found that in contrast to my hypothesis, warming decreased decomposition in Kangerlussuaq, where the soil was drier and contained less carbon than in Kilpisjärvi. I found no effects of grazing on decomposition, plant community traits nor soil characteristics in neither of the study locations. Neither did I find any consistent associations between changes in decomposition and changes in plant community traits, indicating that the effect of litter quality on decomposition is minor in these areas likely rather limited by climate. I found an association for increased decomposition when plant community C:N ratio and C:P ratio increased as a response to warming, but only in Kilpisjärvi, and since increased plant community C:N and C:P ratios are linked to resistant litter this positive effect is unlikely driven by enhanced litter quality. However, I did find a positive relationship between increased root biomass and increased decomposition as a response to warming that was consistent across areas and grazing regimes, indicating that warming can boost decomposition in different tundra habitats by promoting root growth.
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