Anxiety and depression are highly prevalent diseases with common heritable elements, but the particular genetic mechanisms and biological pathways underlying them are poorly understood. Part of the challenge in understanding the genetic basis of these disorders is that they are polygenic and often context-dependent. In my thesis, I apply a series of modern statistical tools to ascertain some of the myriad genetic and environmental factors that underlie fear-related behaviours in nearly two thousand heterogeneous stock mice, which serve as animal models of anxiety and depression. Using a Bayesian method called Sparse Partitioning and a frequentist method called Bagphenotype, I identify gene-by-sex interactions that contribute to variation in fear-related behaviours, such as those displayed in the elevated plus maze and the open field test, although I demonstrate that the contributions are generally small. Also using Bagphenotype, I identify hundreds of gene-by-environment interactions related to these traits. The interacting environmental covariates are diverse, ranging from experimenter to season of the year. With gene expression data from a brain structure associated with anxiety called the hippocampus, I generate modules of co-expressed genes and map them to the genome. Two of these modules were enriched for key nervous system components — one for dendritic spines, another for oligodendrocyte markers — but I was unable to find significant correlations between them and fear-related behaviours. Finally, I employed another Bayesian technique, Sparse Instrumental Variables, which takes advantage of conditional probabilities to identify hippocampus genes whose expression appears not just to be associated with variation in fear-related behaviours, but cause variation in those phenotypes.

Externe Repräsentationen sind für das Verständnis und die Vermittlung chemischer Phänomene und Konzepte essenziell. Lernende werden mit einer Vielzahl an Darstellungen konfrontiert, mit denen sie geeignet umgehen müssen, um die darin transportierten Inhalte zu erfassen. Eine wichtige Voraussetzung für die flexible Verwendung mehrerer Repräsentationen im Lehr- und Lernprozess stellt die sogenannte Translationsfähigkeit dar, welche das Überführen verschiedener Darstellungsformen ineinander beschreibt. Empirische Studien weisen dahingehend auf Defizite bei Lernenden hin. Demzufolge untersucht die vorliegende Arbeit in einer quantitativen Querschnittstudie, inwiefern (a) Übersetzungswege und (b) zu übersetzende Stoffklassen die Übersetzungsschwierigkeit beeinflussen und (c) welche Zusammenhänge zwischen personenbezogenen Eigenschaften und der Translationsfähigkeit bei Lernenden bestehen. Die Stichprobe umfasst Lernende der 10. und 11. Jahrgangsstufe des Bundeslandes Berlin. Für die Erfassung der Translationsfähigkeit wurde ein Erhebungsinstrument konzipiert, dessen Aufgaben in einem Think-Aloud-Setting (N = 10) und in einer quantitativen Vorstudie (N = 225) pilotiert wurden. Die Auswertung der Daten erfolgte unter Anwendung von Item-Response-Theorie sowie Zusammenhangsanalysen. Die Ergebnisse (N = 629) zeigen, dass sich Übersetzungswege zwischen Moleküldarstellungen geringfügig in der Übersetzungsschwierigkeit unterscheiden und ähnlich hohe Anforderungen an die Translationsfähigkeit stellen (a). Zu übersetzende Stoffklassen zeigen Unterschiede in den Übersetzungsschwierigkeiten und damit in den Translationsanforderungen an Lernende (b). In einer multiplen Regression konnten personenbezogene Eigenschaften wie deklaratives Fachwissen und Mental Load als Prädiktoren der Translationsfähigkeit identifiziert werden (c). Die Befunde bieten damit Ansatzpunkte zum Umgang mit Lerngelegenheiten mit Translationsanforderungen und Möglichkeiten für Anschlussforschung. / External representations are important to understand and teach chemical phenomena and concepts. Students are faced with a multitude of representations, which they have to deal with appropriately to comprehend the content conveyed to them. An important prerequisite for the flexible use of several representations in teaching and learning processes is the so-called translation ability, which includes switching from one form of representation to another. However, empirical work reveals deficits among students. To shed light on these deficits, this work uses a quantitative cross-sectional study to investigate how the variables (a) translation path and (b) chemical class influence the translation difficulty, and (c) which correlations exist between students’ personal characteristics and their translation ability. The sample consists of 10th and 11th grade students from high schools in Berlin. To assess translation ability, a multiple-choice test was developed and validated in a think-aloud setting (N = 10) and a quantitative pre-study (N = 225). The data were analyzed using item response theory, as well as correlation and regression analyses. The results (N = 629) indicated that translation paths between molecular representations differ only slightly in terms of translation difficulty and have similarly high translation ability requirements (a). Regarding chemical classes, differences in translation difficulty and thus translation requirements for students could be identified (b). In a multiple regression, person-related variables such as declarative knowledge and mental load could be identified as predictors of translation ability (c). Thereby, these findings provide first principles for dealing with learning opportunities that have translation requirements and possibilities for follow-up research.