Introduction Introducing Accessibility theory 0.1 On the role of context Utterances cannot be processed and interpreted on their own. ...

Discourse and grammar often complement each other, each imposing a different set of constraints on speakers' utterances. Discourse constraints are global, pertaining to text coherence, and/or to interpersonal relations. Grammatical constraints are local, pertaining to possible versus impossible structures. Yet, the two must meet in natural discourse. At every point during interaction speakers must simultaneously satisfy both types of constraints in order to communicate properly. It is also during conversational interaction that language change somehow takes place. This overview first explains (...) and exemplifies how discourse constraints guide addressees in selecting specific grammatical forms at different points in the interaction. It then examines the relationship between discourse and grammar from a grammaticization point of view, demonstrating how a subset of discourse patterns turn grammatical. The central theme is then that discourse depends on grammar, which in turn depends on discourse. (shrink)

DNA methylation plays a role in the repression of gene expression in animal cells. In the mouse preimplantation embryo, most genes are unmethylated but a wave of de novo methylation prior to gastrulation generates a bimodal pattern characterized by unmethylated CpG island‐containing housekeeping genes and fully modified tissue‐specific genes. Demethylaton of individual genes then takes place during cell type specific differentiation, and this demodification may be a required step in the process of transcriptional activation. DNA modification is also involved in (...) the maintenance of gene repression on the inactive X chromosome in female somatic cells and the marking of parental alleles at genomically imprinted gene loci. (shrink)