Molecular Mechanisms of Sexual Dimorphism in Threespine Stickleback

Sexual dimorphism is commonly understood as differences in external features, such as morphological features or coloration. However, it can more broadly encompass behavior and physiology and at the core of these differences is the genetic mechanism – mRNA and protein expression. How, and which, molecular mechanisms influence sexually dimorphic features is not well understood thus far. DNA, RNA and proteins are the template required to create the phenotype of an individual, and they are connected to each other via processes of transcription and translation. As the genome of males and females are almost identical with the exception of the few genes on the sex chromosome or the sex-determining alleles (in the case of organisms without sex chromosomes), it is likely that many of the downstream processes resulting in sexual dimorphism are produced by changes in gene regulation and result from a regulatory cascade and not from a vastly different gene composition. Thus, in this thesis a systems biology approach is used to understand sexual dimorphism at all molecular levels and how different genomic features, e.g. sex chromosome evolution, can affect the interplay of these molecules. The threespine stickleback, Gasterosteus aculeatus, is used as the model to investigate molecular mechanisms of sexual dimorphism. It has well-characterized ecology and behavior, especially in the breeding season when sexual dimorphism is high. Moreover, threespine stickleback has a recently evolved Y chromosome in the early stages of sex chromosome evolution, characterized by a lack of recombination leading to degeneration (i.e. gene loss). The aim of my thesis is to investigate how the genotype links to the molecular phenotype and relates to differences in molecular expression between males and females. Based on previous research on sex differences in mRNA expression, I investigated sex-biased protein expression in adult fish outside the breeding season to see if differences persisted after translation. As sex-biased expression also prevailed in the proteome and previous transcription expression seemed to be related to the sex chromosomes, I investigated the genome level with a particular focus on the sex-chromosomes. I characterized the status of Y chromosome degeneration in the threespine stickleback and its effects on gene function. Furthermore, since the degeneration process leaves genes in a single copy in males, I examined whether the resulting dosage difference of messenger RNA for hemizygous genes is compensated as it is in other organisms. In addition, threespine sticklebacks have wellcharacterized behavioral differences related to the male’s social status during the breeding season. To understand the connection between the genotype and behavior, I examined gene expression patterns related to breeding behavior using dominant and subordinate males as well as female

Impacts of capacity remunerative mechanisms on cross-border trade

The European ambitious targets to increase the share of renewable generation pose a challenge to the generation adequacy. Many European member states are concerned that energy-only markets alone might not be able to deliver sufficient capacity required to meet the future electricity demand and back up shortfalls of energy from renewable energy sources (RES) during periods of low wind and sun. Many EU members consider to re-design their energy-only markets and establish different forms of capacity remunerative mechanisms (CRMs) to maintain the security of supply. There is a certain concern that market design changes at the level of EU member countries might conflict with the European goal of a single market. As soon as many European markets are highly interconnected, uncoordinated CRMs might create negative crossborder effects and hinder the achievement of the Internal Electricity Market in Europe. The pros and cons of capacity markets are well examined at the national level. However, the cross-border effects of capacity markets within the European market aiming at higher integration have received less attention. This doctoral dissertation examines the cross-border effects of unilateral implementation of CRMs applying both theoretical and case study analyses. The results show that capacity remunerative mechanisms (CRMs) may cause negative cross-border effects, especially if they are implemented unilaterally.

Natural born weight gainers: The mechanisms of obesity in transgenic mice overexpressing neuropeptide Y

Neuropeptide Y (NPY) is a neurotransmitter promoting energy storage by activating Y-receptors and thus affecting food intake, thermogenesis and adipose tissue metabolism. NPY is expressed both in the central and sympathetic nervous system. Hypothalamic NPY is known to stimulate feeding, but the effects of noradrenergic neuron NPY are more ambiguous. Chronic stress stimulates fat accumulation via NPY release from noradrenergic neurons. Furthermore, polymorphism in the human Npy gene has been associated with metabolic disturbances and increased NPY secretion after sympathetic stimulation. The main objective of this study was to clarify the mechanisms of noradrenergic neuron NPY in the development of obesity. The metabolic phenotype of a homozygous mouse overexpressing NPY in the brain noradrenergic neurons and sympathetic nervous system (OE-NPYDβH mouse) was characterized. OE-NPYDβH mice had an increased fat mass and body weight, which caused impairments of glucose metabolism and hyperinsulinaemia with age. There were no differences in energy intake or expenditure, but the sympathetic tone was down-regulated and the endocannabinoid system activated. Furthermore, peripheral Y2-receptors in energy-rich conditions played an important role in mediating the fat-accumulating effect of NPY. These results indicate that noradrenergic neuron NPY promotes obesity via direct effects in the periphery and by modulating the sympatho-adrenal and endocannabinoid systems. Additionally, NPY in the central noradrenergic neurons is believed to possess many important roles. The phenotype of the OE-NPYDβH mouse resembles the situations of chronic stress and Npy gene polymorphism and thus these mice may be exploited in testing novel drug candidates for the treatment of obesity.

Interactions of decision mechanisms in an entrepreneurial firm’s journey to become a major player in its industry

This study discusses the interactions of different decision-making mechanisms in the process of change of a successful entrepreneurial dairy firm in Vietnam. The purpose of the study is to construct a theoretical framework, which explains the interactions between effectual and causal decision-making processes in different phases of business, and to provide a real life example with practical recommendations for entrepreneurs and managers. In order to achieve this purpose, a preliminary theoretical framework was built, using process theories applied to different decision making modes, referred to as causation and effectuation. The case was studied through ethnographic research method, with three semi-structured interviews, one unstructured interview, secondary data and observations within four months in 2013-2014. After the data was analyzed, a modified framework was drawn from the result. The finding of this study shows that there was an interaction between effectual and causal decision-making processes in different stages of the company’s development. The entrepreneur applied effectual decision-making process to develop a unique business model and a new dairy market segment. However, when a new market demand arose, the company’s resources became insufficient, they thus had to shift to causation process to adapt to market change. Simultaneously, with better-accumulated resources, the entrepreneur continued the effectuation process to create another brand new dairy market segment. This study, thus, contributes to effectuation theory, emphasizing the necessity of combining effectual and causal decision-making processes in different phases of business. It is suggested that business would develop with an effectual process until a business model is viable for growth. It continues to use this process up to a certain degree. When the market changes, the company needs to collect more means to adapt to the changes. They need to set new goals and this is a shift to the use of causal process, which builds on prediction. It uses goals and teleology as driving mechanisms and tries to exploit and fill potential resource gaps to achieve these goals. At the same time, there are new iterations that look to establish new lines or types of business with the given means, which are now well established. This again employs effectual mechanisms, which are based on evolutionary process, until they reach the stage of viable tested business model. Moreover, this study hopes to provide know-how to entrepreneurs and managers of small companies in similar situations, suggesting how to combine effectual and causal decision-making processes to deal with various circumstances in different times.