The origin of the first RNA polymers is central to most current theories regarding the origin of life. However, difficulties associated with the prebiotic formation of RNA have lead many researchers to conclude that simpler polymers, or proto-RNAs, preceded RNA. These earlier polymers would have been replaced by RNA over the course of evolution. A remaining difficulty for this theory is that the de novo synthesis of a feasible proto-RNA has not yet been demonstrated by plausible prebiotic reactions. This thesis focuses on two problems associated with prebiotic proto-RNA synthesis: The formation of nucleosides and the necessity of reversible backbone linkages for error correction in nucleic acid polymers. "The Nucleoside Problem", or the lack of success in forming pyrimidine nucleosides by plausible prebiotic reactions, represents a significant stumbling block to the RNA world hypothesis. Nearly four decades ago Orgel and coworkers demonstrated that the purine nucleosides adenosine and inosine are synthesized by heating and drying their respective bases and ribose in the presence of magnesium, but these reaction conditions do not yield the pyrimidine nucleosides uridine or cytidine from their respective bases. In this thesis a potential solution to The Nucleoside Problem is hypothesized based upon a proposed chemical mechanism for nucleoside formation. This hypothesis is supported by the successful synthesis of 2-pyrimidinone nucleosides by a plausible prebiotic reaction in good yield, demonstrating that pyrimidine nucleosides could have been available in the prebiotic chemical inventory, but that uridine and cytidine were likely not abundant. Reversible backbone linkages are necessary to provide a mechanism for error correction in non-enzymatic template-directed syntheses of proto-RNAs. In this thesis, acetals are explored as low-energy, reversible linkage groups for nucleosides in polymers. The synthesis of glyoxylate-acetal nucleic acids (gaNAs) through simple heating-drying reactions from neutral aqueous solutions is demonstrated, and these linkages are shown to be hydrolytically stable under a considerable range of solution conditions. Computational models demonstrate that the glyoxylate linkage is an excellent electronic and isosteric replacement for phosphate. Molecular dynamics simulations also indicate that a gaNA duplex would have structural properties that closely match a phosphate-linked RNA helix, suggesting the possibility for cross-pairing between gaNAs and RNAs, allowing for sequence transfer and genetic continuity through the evolution from proto-RNAs to RNA. The principles illustrated in this thesis by 2-pyrimidinone nucleoside and gaNA synthesis can be extended to other prebiotic condensation reactions. Factors affecting condensation yield, such as thermodynamics, kinetics, reactant solubility, and salt effects, are summarized herein.

Evolutionäre Herangehensweisen hatten in der Persönlichkeitspsychologie nicht den gleichen Erfolg wie in anderen Bereichen der Psychologie. In dieser Dissertation werden zwei alternative evolutionäre Herangehensweisen an die Persönlichkeitspsychologie diskutiert und angewendet. Die evolutionsgenetische Herangehensweise fragt, warum genetische Varianz in Persönlichkeitsunterschieden existiert. Im ersten Teil dieser Dissertation werden verschiedene evolutionsgenetische Mechanismen, die genetische Varianz erklären können, verglichen. Auf Grundlage evolutionsgenetischer Theorie und empirischen Befunden aus der Verhaltensgenetik und Persönlichkeitspsychologie wird geschlussfolgert, dass ein Mutations-Selektions-Gleichgewicht genetische Varianz in Intelligenz gut erklären kann, während ausgleichende Selektion durch Umweltheterogenität die plausibelste Erklärung für genetische Unterschiede in Persönlichkeitseigenschaften ist. Komplementär zur evolutionsgenetischen Herangehensweise beginnt die „Life History“-Herangehensweise damit, wie Menschen ihre Ressourcen in evolutionär relevante Lebensbereiche investieren. Im zweiten Teil der Dissertationsschrift wird diese Herangehensweise am Beispiel von Investitionsunterschieden in Langzeit- versus Kurzzeit-Paarungstaktiken (wie im Konstrukt der Soziosexualität abgebildet) erläutert. Zwei neue Maße zur Erfassung von Soziosexualitätskomponenten werden vorgestellt. Während das revidierte Soziosexuelle Orientierungsinventar (SOI-R) ein Fragebogen zur Erfassung der Facetten „Verhalten“, „Einstellung“ und „Begehren“ ist, wurde mit dem Single-Attribute Impliziten Assoziationstest (SA-IAT) eine neue Methode zur indirekten Erfassung impliziter Soziosexualität entwickelt. Beide Maße zeigten konkurrente Validität in Onlinestudien, aber nur der SOI-R erwies sich als prädiktiv für Paarungstaktiken, einschließlich beobachtetem Flirtverhalten sowie der Zahl der Sexualpartner und Veränderungen im Beziehungsstatus innerhalb der nächsten 12 Monate. / Evolutionary approaches have not been as successful in personality psychology as they were in other areas of psychology. In this thesis, two alternative evolutionary approaches to personality psychology are discussed and applied. The evolutionary genetic approach asks why genetic variance in personality differences exists. In the first part of this thesis, three evolutionary genetic mechanisms that could explain genetic variance in personality differences are assessed: selective neutrality, mutation-selection balance, and balancing selection. Based on evolutionary genetic theory and empirical results from behavior genetics and personality psychology, it is concluded that selective neutrality is largely irrelevant, that mutation-selection balance seems best at explaining genetic variance in intelligence, and that balancing selection by environmental heterogeneity seems best at explaining genetic variance in personality traits. Complementary to the evolutionary genetic approach, the life history approach starts with how people allocate their resources to evolutionarily relevant life tasks. In the second part of this thesis, differences in the allocation to long-term versus short-term mating tactics (as reflected in the construct of sociosexuality) are used as a case to exemplify this approach. Two new measures for the assessment of sociosexuality components are presented. While the revised Sociosexual Orientation Inventory (SOI-R) is a questionnaire that assesses the facets Behavior, Attitude and Desire, the sociosexuality Single-Attribute Implicit Association Test (SA-IAT) is a new methodic development aimed to assess implicit sociosexuality indirectly. Both measures showed concurrent validity in online studies, but only the SOI-R facets were predictive of mating tactics, including observed flirting behavior, as well as for the number of sexual partners and changes in romantic relationship status over the following 12 months.

Nach einem ausführlichem Überblick über den Kenntnisstand der Genetik und Neurowissenschaft von allgemeiner Intelligenz und einer methodischen Anmerkung zur Notwendigkeit der Berücksichtigung latenter Variablen in den kognitiven Neurowissenschaften am Beispiel einer Reanalyse publizierter Ergebnisse wir das am besten etablierte Gehirnkorrelat der Intelligenz, die Gehirngröße, aus evolutionsgenetischer Perspektive neu betrachtet. Schätzungen des Koeffizienten additiv-genetischer deuten an, dass es keine rezente direktionale Selektion auf Gehirngröße gegeben hat, was ihre Validität als Proxy für Intelligenz in evolutionären Studien in Frage stellt. Stattdessen deuten Korrelationen der Gesichtssymmetrie älterer Männer mit Intelligenz und Informationsverarbeitungsgeschwindigkeit an, dass organismusweite Entwicklungsstabilität eine wichtige Grundlage von unterschieden in kognitiven Fähigkeiten sein könnte. Im zweiten Teil dieser Arbeit geht es vornehmlich um die Alterung kognitiver Fähigkeiten, beginnend mit einem allgemeinen Überblick. Daten einer Stichprobe von über 130 Individuen zeigen dann, dass die Integrität verschiedener Nervenbahnen im Gehirn hoch korreliert, was die Extraktion eines Generalfaktors der Traktintegrität erlaubt, der mit Informationsverarbeitungsgeschwindigkeit korreliert. Der einzige Trakt mit schwacher Ladung auf diesem Generalfaktor ist das Splenium des Corpus Callosum, welches mit Veränderungen der Intelligenz über 6 Jahrzehnte korreliert und den Effekt des Bet2 adrenergischem Rezeptorgens (ADRB2) auf diese Veränderung mediiert, möglicherweise durch Effekte auf neuronale Komopensationsprozesse. Schließlich wird auf Basis neuer Analyseverfahren für Magnetresonanzdaten gezeigt, dass vermehrte Eiseneinlagerungen im Gehirn, vermutlich Marker für zerebrale Mikroblutungen, sowohl mit lebenslang stabilen Intelligenzunterschieden als auch mit der altersbedingten Veränderung kognitiver Fähigkeiten assoziiert sind. / After an extensive review of what is known about the genetics and neuroscience of general intelligence and a methodological note emphasising the necessity to consider latent variables in cognitive neuroscience studies, exemplified by a re-analysis of published results, the most well-established brain correlate of intelligence, brain size, is revisited from an evolutionary genetic perspective. Estimates of the coefficient of additive genetic variation in brain size suggest that there was no recent directional selection on brain size, questioning its validity as a proxy for intelligence in evolutionary analyses. Instead, correlations of facial fluctuating asymmetry with intelligence and information processing speed in old men suggest that organism-wide developmental stability might be an important cause of individual differences in cognitive ability. The second half of the thesis focuses on cognitive ageing, beginning with a general review. In a sample of over 130 subjects it has then been found that the integrity of different white matter tracts in the brain is highly correlated, allowing for the extraction of a general factor of white matter tract integrity, which is correlated with information processing speed. The only tract not loading highly on this general factor is the splenium of the corpus callosum, which is correlated with changes in intelligence over 6 decades and mediates the effect of the beta2 adrenergic receptor gene (ADRB2) on cognitive ageing, possibly due to its involvement in neuronal compensation processes. Finally, using a novel analytic method for magnetic resonance data, it is shown that more iron depositions in the brain, presumably markers of a history of cerebral microbleeds, are associated with both lifelong-stable intelligence differences and age-related decline in cognitive functioning.

The Kin Selection Hypothesis proposes that the genes associated with male androphilia (i.e., sexual attraction/arousal to adult males) may be maintained over evolutionary time if the fitness costs of not reproducing directly are offset by increasing one’s indirect fitness. Theoretically, this could be accomplished by allocating altruism toward kin which would increase the recipient’s ability to survive and reproduce. Evidence for this hypothesis has been garnered through research conducted in Samoa however, no support has been garnered from research conducted in more industrialized cultures (i.e., USA, UK, Japan). In this thesis, I use a Canadian population to examine: (1) the role geographic proximity plays in the expression of androphilic male avuncularity and (2) whether androphilic males direct altruism toward the children of friends who might represent proxies for nieces and nephews in more industrialized cultures. Other sociocultural factors that potentially influence the expression of androphilic male avuncularity are also discussed. / ix, 81 leaves ; 29 cm

Evolutionary biology is not a specialty, like genetics or development - it is an explanation of what is investigated by all biological specialties. Thus, the goal of this dissertation was to study both micro- and macroevolutionary processes in a multi-disciplinary framework.<p>Population genetics, conservation, and phylogeny inference. The Jamaican boa (Epicrates subflavus) is an endemic species, whose natural populations greatly and constantly declined since the late 19th century, mainly due to predation by introduced species, human persecution, and habitat destruction. Using species-specific nuclear microsatellite loci and mitochondrial sequences, we investigated the population structure of this endangered reptile. All analyses pinpointed to an Eastern versus (Western+Central) pattern of differentiation in agreement with geological data and patterns of differentiation uncovered in other vertebrate and invertebrate Jamaican species. The same molecular markers were employed on 80 Jamaican boas of the European captive breeding program. This approach allowed us to (i) clarify all ambiguities in the studbook, (ii) correct parental allocation errors and (iii) assess the genetic diversity and the level of inbreeding of the current captive population. These results provide important insights for guiding the development of proper ex-situ and in-situ species survival and habitat management plans for this vulnerable snake. In the same framework of classical evolutionary genetics, we performed preliminary analyses of cytochrome b-like sequences in representatives of all cetacean families (but one), and revealed the presence of at least four nuclear mitochondrial pseudogenes that were independently inserted into the nuclear genome. <p>Evo-Devo. The emergence of Evolutionary Developmental biology has caused a partial shift in the criteria for the selection of model species. Thus far, the main criterion was the relevance of a species for understanding human biology, whereas in the frame of the new discipline, it is the understanding of the generative mechanisms underlying biological diversity that is put forward. We discussed a few criteria and limitations of major relevance to the choice of model species for Evo-Devo studies, and applied a pragmatic approach to identify possible model species within Amniotes. <p>Moreover, we developed MANTiS, an application pipeline that aims at integrating genomic, functional and expression data with evolutionary concepts, thus constituting the missing link between multi-species genome comparisons and functional analyses. Using MANTiS, we proceeded in the analysis of 35 metazoan full genomes for identifying all lineage-specific gene gains and losses. These results were combined with functional and expression analyses, and we demonstrated the much higher performance of MANTiS against popular databases of ortholog clusters (InParanoid, OrthoMCL, RoundUp).<p>Finally, preliminary results of our attempt to adapt the new revolutionary technology of DNA sequencing in microfabricated high-density picoliter reactors (developed by 454/Roche) to the ultra-fast sequencing of brain full transcriptomes in multiple reptilian species are highly promising. As an example, the Crocodylus sample generated more than 72 Mbases (per run), which were successfully assembled in approximately 31,000 contigs. One third of the latter could be matched to known sequences in the transcriptome of related species. After fine-tuning of the in silico analyses, and incorporation of genomic sequence data, we expect our approach to provide important insights not only in the evolution of central nervous system novelties in vertebrates, but in transcriptomes in general as the brain transcriptome is one of the most complex among all organs.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Indiana University-Purdue University Indianapolis (IUPUI) / RNA-binding proteins (RBPs) are vital post-transcriptional regulatory molecules in transcriptome of mammalian species. It necessitates studying their expression dynamics to extract how post-transcriptional networks work in various mammalian tissues. RNA binding proteins (RBPs) play important roles in controlling the post-transcriptional fate of RNA molecules, yet their evolutionary dynamics remains largely unknown. As expression profiles of genes encoding for RBPs can yield insights about their evolutionary trajectories on the post-transcriptional regulatory networks across species, we performed a comparative analyses of RBP expression profiles across 8 tissues (brain, cerebellum, heart, lung, liver, lung, skeletal muscle, testis) in 11 mammals (human, chimpanzee, gorilla, orangutan, macaque, rat, mouse, platypus, opossum, cow) and chicken & frog (evolutionary outgroups). Noticeably, orthologous gene expression profiles suggest a significantly higher expression level for RBPs than their non-RBP gene counterparts, which include other protein-coding and non-coding genes, across all the mammalian tissues studied here. This trend is significant irrespective of the tissue and species being compared, though RBP gene expression distribution patterns were found to be generally diverse in nature. Our analysis also shows that RBPs are expressed at a significantly lower level in human and mouse tissues compared to their expression levels in equivalent tissues in other mammals: chimpanzee, orangutan, rat, etc., which are all likely exposed to diverse natural habitats and ecological settings compared to more stable ecological environment humans and mice might have been exposed, thus reducing the need for complex and extensive post-transcriptional control. Further analysis of the similarity of orthologous RBP expression profiles between all pairs of tissue-mammal combinations clearly showed the grouping of RBP expression profiles across tissues in a given mammal, in contrast to the clustering of expression profiles for non-RBPs, which frequently grouped equivalent tissues across diverse mammalian species together, suggesting a significant evolution of RBPs expression after speciation events. Calculation of species specificity indices (SSIs) for RBPs across various tissues, to identify those that exhibited restricted expression to few mammals, revealed that about 30% of the RBPs are species-specific in at least one tissue studied here, with lung, liver, kidney & testis exhibiting a significantly higher proportion of species specifically expressed RBPs. We conducted a differential expression analysis of RBPs in human, mouse and chicken tissues to study the evolution of expression levels in recently evolved species (i.e., humans and mice) than evolutionarily-distant species (i.e., chickens). We identified more than 50% of the orthologous RBPs to be differentially expressed in at least one tissue, compared between human and mouse, but not so between human and an outgroup chicken, in which RBP expression levels are relatively conserved. Among the studied tissues (brain, liver and kidney) showed a higher fraction of differentially expressed RBPs, which may suggest hyper- regulatory activities by RBPs in these tissues with species evolution. Overall, this study forms a foundation for understanding the evolution of expression levels of RBPs in mammals, facilitating a snapshot of the wiring patterns of post-transcriptional regulatory networks in mammalian genomes. In our second study, we focused on elucidating novel features of post-transcriptional regulatory molecules called as circRNA from LongPolyA RNA-sequence data. The debate over presence of nonlinear exon splicing such as exon-shuffling or formation of circularized forms has finally come to an end as numerous repertoires have shown of their occurrence and presence through transcriptomic analyses. It is evident from previous studies that along with consensus-site splicing non-consensus site splicing is robustly occurring in the cell. Also, in spite of applying different high-throughput approaches (both computational and experimental) to determine their abundance, the signal is consistent and strongly conforming the plausible circularization mechanisms. Earlier studies hypothesized and hence focused on the ribo-minus non-polyA RNA-sequence data to identify circular RNA structures in cell and compared their abundance levels with their linear counterparts. Thus far, the studies show their conserved nature across tissues and species also that they are not translated and preferentially are without poly (A) tail, with one to five exons long. Much of this initial work has been performed using non-polyA sequencing thus probably underestimates the abundance of circular RNAs originating from long poly (A) RNA isoforms. Our hypothesis is if the circular RNA events are not the artifact of random events, but has a structured and defined mechanism for their formation, then there would not be biases on preferential selection / leaving of polyA tails, while forming the circularized isoforms. We have applied an existing computational pipeline from earlier studies by Memczack et. al., on ENCODE cell-lines long poly (A) RNA-sequence data. With the same pipeline, we achieve a significant number of circular RNA isoforms in the data, some of which are overlapping with known circular RNA isoforms from the literature. We identified an approach and worked upon to identify the precise structure of circular RNA, which is not plausible from the existing computational approaches. We aim to study their expression profiles in normal and cancer cell-lines, and see if there exists any pattern and functional significance based on their abundance levels in the cell.

No description available.

Sympatric speciation has received much attention both empirically and theoretically. However, the contribution of sympatric speciation to biodiversity remains unclear. One piece missing from the speciation puzzle is the plausibility of sympatric ecological divergence of species through adaptation in polygenic traits. I consider an environment consisting of two niches, where one value of the trait is advantageous in only one niche, and vice versa. The selection regime is described by a trade-off in viabilities between the niches. These polygenic traits can, and often do, involve epistatic interactions among and between loci, so that the contribution of the alleles to viability deviates from additivity. Epistasis then also affects the curvature of the trade-offs: predominant less-than-additive epistasis turns the curve towards concavity and predominant more-than-additive towards convexity. The curvature of the trade-off plays a crucial role in the evolution of populations. With a convex trade- off, extreme values of the trait are favored and the population tends to diverge, but relatively stringent symmetry in strength of selection within the niches and the niche proportions is necessary to maintain polymorphism. In this study I use two and three- locus haploid versions of Levene's model to...