Flatworm DNA methylation: deciphering the mark and characterising the machinery.

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We are all familiar with the subject of genetics, which describes how the fundamental unit of inheritance (the gene) is passed on from parent to offspring. Changes in the underlying DNA sequence that make up our inherited genes help explain why differences (eye colour, eye shape, chin size, etc.) in our outward appearance (phenotype) occur.However, genetics cannot fully explain the wide-ranging phenotypic diversity exhibited by all organisms on this planet. To do so in a systematic manner, we also have to consider another type of inheritance system called epigenetics. Epigenetics is the study of inherited changes in gene function (leading to different phenotypes) that cannot be explained by changes in the underlying DNA sequence of the gene. In other words, epigenetics attempts to explain everything that genetics cannot. One particular type of epigenetic process responsible for inherited changes in phenotype is facilitated by DNA methylation. Loss of DNA methylation regulation has been extensively studied in humans and is associated with cancer, obesity, immunodeficiencies and intellectual disabilities. Recent studies have additionally demonstrated that heritable DNA methylation patterns are influenced by our interaction with environmental (chemicals, drugs, etc.) factors. However, very little is known about DNA methylation or the processes that regulate it in other animal systems, especially invertebrates.Flatworms are a tremendously important invertebrate group (within the phylum Platyhelminthes) responsible for many economically- and biomedically-relevant parasitic diseases. These parasitic invertebrates undergo extensive developmental changes throughout their complicated lifecycles, which often involves interaction with more than one host or environment. Does environmentally influenced DNA methylation contribute to the success of parasites like these? If so, how does this occur and what genes are targeted by this epigenetic mechanism?Working in Aberystwyth, we will apply state of the art molecular biology tools to try and understand how DNA methylation regulates flatworm development. We have already found that DNA methylation is present in all three classes (Trematoda, Cestoda and Monogenea) of parasitic platyhelminth and that the enzymes responsible for these genome modifications are highly conserved. Using a model platyhelminth (Schistosoma mansoni), our project aims to further characterise the enzyme responsible for flatworm DNA methylation and to identify the genes specifically targeted by the DNA methylation machinery. By doing so in a synergistic manner, we expect to discover new roles for this epigenetic process during animal evolution. This information may eventually lead to novel ways to combat parasitic diseases.