Browsing by Subject "epigenetiikka"

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  • Matikainen, Riikka (Helsingin yliopisto, 2019)
    In this master’s theses, Finnish biology teachers’ needs for material for continuing education and educational material for upper secondary school in epigenetics were studied. Two sets of educational materials, continuing educational material for teachers and educational material for upper secondary school teaching was produced accordant with the results. Epigenetics is used to describe stable alterations in gene expression which do not consider mutations in DNA sequence. DNA methylation, histone modifications and chromatin remodelling are the main epigenetic mechanisms to affect gene expression. Epigenetic modification patterns can alter de novo, or they can be originated by some environmental factor. Epigenetic regulation was introduced as a new subject matter in National Core Curriculum for General Upper Secondary Schools 2015 in Finland. Epigenetics is a relatively new branch in biology, and as a result many teachers have not studied the subject matter at the university. Continuing educational material is needed to update their knowledge. Biology teachers’ needs for material in epigenetics were studied with a survey which was distributed to the Biology and Geography Teachers’ Union’s e-mail list subscribers. Data was analysed qualitatively and quantitatively. In order to produce continuing educational material for teachers, literature regarding teacher competence, adult education and Finnish biology teachers’ subject expertise was examined. The concept of constructivist learning, and conceptual change were applied in the production of educational material for upper secondary school teaching. Relevant scientific literature in epigenetics was gathered and used to produce both sets of materials. In the study survey, the teachers reported specific individual educational needs which were acknowledged in the production of both sets of materials, alongside literature listed earlier. The survey showed that one of 33 biology teachers had studied epigenetics at the university, 20 of 33 teachers independently and 13 of 33 hadn’t studied epigenetics at all. The extent of the teachers’ studies in epigenetics was most often elementary and the main motivation to study epigenetics independently was a desire to handle the basics. The most common resource teachers used to study epigenetics was non-scientific magazines. Among the teachers who had not studied epigenetics at all, lack of time was the most common reason mentioned. However, 14 teachers described epigenetics as an important subject matter. Three teachers reported that they lack the expertise in teaching epigenetics and three felt that textbooks don’t offer support in teaching epigenetics. Online material and expert lectures were the most common continuing education material forms requested. Regarding the content of the continuing educational material for teachers, the most common requests were that the material should include the basics of epigenetics and practical examples. The form of educational material for upper secondary school teaching was most commonly requested to be online text or educational video. Regarding the content of the educational material for upper secondary school teaching, the most common requests among teachers were a summary of the theory of epigenetics and practical examples. The continuing educational material for teachers produced in this thesis consists of an introduction part and four parts about different subjects in epigenetics. The titles of the parts are: 1) What is epigenetics? 2) Molecular mechanisms of epigenetic gene regulation 3) Epigenetic gene regulation and 4) Epigenetic inheritance. The material was designed in a way that texts 3) and 4) are possible to comprehend without studying text 2) about molecular mechanisms of epigenetic regulation. The educational material for upper secondary school teaching consists of seven parts. At the beginning there is an introduction to teachers which is followed by six separate parts for students. Each part has a “Rehearse before reading”-box which introduces students to the subject and encourages rehearsal of biological concepts and vocabulary which are necessary for comprehending each part. After each part there are questions which test students’ learning as well as encourage to apply freshly acquired knowledge about epigenetics to other biological contexts. Titles for different parts are: 1) What is epigenetics? 2) Epigenetics and nutrition 3) Epigenetics and exercise 4) Epigenetics and mental health 5) Epigenetics and tortoiseshell cats and 6) Epigenetic inheritance. The material has been designed in such a way that the parts can be taught and learned separately. References are provided at the end of both material sets. Both materials produced in this thesis meet the teachers’ requests revealed in the survey. The form of the continuing educational material for teachers is online material, which was one of the most common requests among the teachers who answered the survey. The contents of the material correspond to the teachers requests as well, since most requested contents were the basics of epigenetics and practical examples. The educational material for upper secondary school teaching was requested as online material with a summary of the theory of epigenetics and practical examples, and all these requests were met. Both materials were produced considering relevant theories on pedagogy and adult education. Results of this study cannot be applied nationally in Finland since the sample size was small. Therefore, national relevance of the materials cannot be predicted. Predictions about the impact of the materials on teachers’ and students’ understanding about epigenetics cannot be made either, since learning is an active process which requires effort from the learner. However, a strong case can be made for the produced material, because materials include relevant information and their pedagogic choices can be justified by the literature. This thesis uncovered many questions for future research. For example, the efficacy of the materials could be studied in a practical classroom situation. Other possible questions for research or study designs could be about biology teachers’ expertise and continuing education in Finland.
  • Ahola, Laura (Helsingin yliopisto, 2021)
    Environment is known to be a strong mediator of embryonal development and the future health of an individual. According to earlier studies, early pregnancy is especially vulnerable to environmental influence. Early embryogenesis is a critical period when epigenetic reprogramming occurs and epigenetic modifications are established. Alcohol is an environmental factor and a teratogen that affects normal epigenetic reprogramming and embryonal development. Prenatal alcohol exposure may contribute to the development of abnormal phenotype or diseases such as fetal alcohol spectrum disorders, FASD. This master’s thesis is part of the epiFASD study at the Environmental Epigenetic Laboratory, University of Helsinki. The study focuses on the environmental impact on the epigenetic mechanisms of FASD and finding possible future biomarkers of early disease. The research group has collected biological samples from a cohort of control and alcohol exposed newborns and their parents. The main aim of the study is to reveal the effects of prenatal alcohol exposure to the epigenetic reprogramming of the newborn. If there are epigenetic fingerprints to be seen in the first developing cells of the embryo, these fingerprints may spread to other cells and tissues by cell proliferation. The main aim of this master’s thesis was to optimize a DNA extraction protocol for the collected buccal cell samples. The optimization was expected to enhance the concentration and purity of the DNA samples for future studies. The group had found earlier prenatal alcohol exposure associated changes on the DNA methylation of alcohol-exposed placentas by genome-wide microarrays. The second aim of the thesis was to observe if similar DNA methylation patterns are found in both buccal epithelial cells and placental tissue. The optimization of the DNA extraction protocol enhanced the concentration but not significantly the purity of the buccal cell DNA samples. The earlier microarray studies with placental tissue revealed an interesting candidate gene and the locus-specific EpiTYPER-analysis confirmed the results: the regulatory regions of the studied gene were less methylated in alcohol-exposed placentas compared to controls. EpiTYPER also showed that methylation levels of the placenta and buccal epithelial cells did not correlate with each other although the changes were similar. Further research needs to be done to confirm if the methylation changes could be used as biomarkers in the diagnosis of alcohol-related disorders.
  • Karell, Pauliina (Helsingin yliopisto, 2018)
    Epigenetiikka on perinnöllisyystieteen ala, jossa tutkitaan ulkoisesti mitattavia ominaisuuksia ilmiasuja, joiden muutokset ilmenevät DNA-juosteen kemiallisina muutoksina. Nämä muutokset eivät ole periytyviä, kuten ihmisen DNA, vaan muokkautuvat ympäristön vaikutuksesta. Metylaatio on eräs epigeneettisistä muutoksista, jotka vaikuttavat geenisäätelyyn. Epigenetiikan avulla on pyritty selittämään eroja muun muassa samanmunaisten kaksosten välillä, ja tutkijoiden mielenkiinto on kohdistunut erityisesti metylaatioon sen helpon mitattavuuden ansiosta. Ihmisiltä erilaisia metyaatioalueita perimästä on kartoitettu noin 400 000, joista osan on tiedetty liittyvän esimerkiksi syövän ilmenemiseen. Tämä tutkielma keskittyy epigeneettisen aineiston tilastolliseen mallinnukseen kaksosaineistossa. Tutkittavaksi ilmiasuksi on valittu ikä, sillä iän on todettu olevan yhteydessä erilaisiin metylaatiomutooksiin. Monissa epigeneettisissä tutkimuksissa käytetään usein kaksosaineistoja, sillä samanmunaiset kaksoset jakavat täysin identtisen perimän keskenään ja usein myös yhteisen kasvuympäristön. Kaksosaineistoa käyttämällä saadaan usein kontrolloitua ympäristöstä johtuvaa vaihtelua, mutta tilastollinen mallinnus vaatii havaintojen riippuvuuden huomioisen. Metylaatioaineistossa saattaa esiintyä myös paljon keskiarvosta poikkeavia havaintoja, jolloin kyseessä on paksuhäntäisestä jakaumasta. Paksuhäntäisissä jakaumissa poikkeavien havaintojen vaikutusta pyritään pienentämään käyttämällä robusteja tilastollisia menetelmiä, jolloin tulokset ovat paremmin yleistettävissä yleiseen väestöön. Tässä tutkielmassa on huomioitu tilastollisessa mallinnuksessa sekä havaintojen riippuvuus että paksuhäntäisyys käyttämällä lineaarista t-sekamallia, sillä t-jakauma on robustimpi vaihtoehto aineiston jakaumaoletukseksi kuin perinteinen normaalijakauma. Lineaarisen t-sekamallin parametrien estimoiminen on toteutettu bayesiläisellä päättelyllä, jossa estimoituja parametreja voidaan tarkastella todennäköisyysjakaumina. Bayesiläisen tilastotieteessä aineistosta tehdään päätelmiä käyttämällä erilaisia todennäköisyysmalleja, mikä mahdollistaa monipuolisen ja joustavan mallimäärittelyn. Käyttämällä erilaista prioritietoa parametrijakaumista, mallin tuloksia voidaan arvioida joustavasti ja monipuolisesti. Tässä tutkielmassa lineaarisen t-sekamallin parametreille on määrätty erilaisia jakaumaoletuksia, jotta perhettä ja kaksosuutta on kyetty mallintamaan riittävästi. Varsinainen estimoitu on toteutettu rakentamalla stokastinen Markovin ketju, jota kutsutaan myös Gibbsin otannaksi. Tässä tutkielmassa selvitettiin iän vaikutusta kolmee erilaiseen metylaatikohtaan ja havaittiin, että kaikissa kolmessa metylaatiokohdassa iän kasvaessa myös metyloituneisuus kasvoi. Eräs kolmesta metylaaatioalueesta on erityisen mielenkiintoinen, sillä vastaavissa tutkimuksissa on saatu samankaltaisia tuloksia ja kyseinen metylaatioalue sijaitsee PDE4C-geeniä ilmentävässä alueessa. Kyseinen geeni vaikuttaa monien muiden solujen aktiivisuuten tuottamalla proteiinia, joka välittää signaaleja solun ulkopuolelle.