Epigenetic Patterns Maintained in Early Caenorhabditis elegans Embryos Can Be Established by Gene Activity in the Parental Germ Cells

Epigenetic information, such as parental imprints, can be transmitted with genetic information from parent to offspring through the germ line. Recent reports show that histone modifications can be transmitted through sperm as a component of this information transfer. How the information that is transferred is established in the parent and maintained in the offspring is poorly understood. We previously described a form of imprinted X inactivation in Caenorhabditis elegans where dimethylation on histone 3 at lysine 4 (H3K4me2), a mark of active chromatin, is excluded from the paternal X chromosome (Xp) during spermatogenesis and persists through early cell divisions in the embryo. Based on the observation that the Xp (unlike the maternal X or any autosome) is largely transcriptionally inactive in the paternal germ line, we hypothesized that transcriptional activity in the parent germ line may influence epigenetic information inherited by and maintained in the embryo. We report that chromatin modifications and histone variant patterns assembled in the germ line can be retained in mature gametes. Furthermore, despite extensive chromatin remodeling events at fertilization, the modification patterns arriving with the gametes are largely retained in the early embryo. Using transgenes, we observe that expression in the parental germline correlates with differential chromatin assembly that is replicated and maintained in the early embryo. Expression in the adult germ cells also correlates with more robust expression in the somatic lineages of the offspring. These results suggest that differential expression in the parental germ lines may provide a potential mechanism for the establishment of parent-of-origin epigenomic content. This content can be maintained and may heritably affect gene expression in the offspring

Evolution of sex-specific pace-of-life syndromes: genetic architecture and physiological mechanisms

Sex differences in life history, physiology, and behavior are nearly ubiquitous across taxa, owing to sex-specific selection that arises from different reproductive strategies of the sexes. The pace-of-life syndrome (POLS) hypothesis predicts that most variation in such traits among individuals, populations, and species falls along a slow-fast pace-of-life continuum. As a result of their different reproductive roles and environment, the sexes also commonly differ in pace-of-life, with important consequences for the evolution of POLS. Here, we outline mechanisms for how males and females can evolve differences in POLS traits and in how such traits can covary differently despite constraints resulting from a shared genome. We review the current knowledge of the genetic basis of POLS traits and suggest candidate genes and pathways for future studies. Pleiotropic effects may govern many of the genetic correlations, but little is still known about the mechanisms involved in trade-offs between current and future reproduction and their integration with behavioral variation. We highlight the importance of metabolic and hormonal pathways in mediating sex differences in POLS traits; however, there is still a shortage of studies that test for sex specificity in molecular effects and their evolutionary causes. Considering whether and how sexual dimorphism evolves in POLS traits provides a more holistic framework to understand how behavioral variation is integrated with life histories and physiology, and we call for studies that focus on examining the sex-specific genetic architecture of this integration

The Freelisting Method

A freelist is a mental inventory of items an individual thinks of within a given category. Freelists reveal cultural " salience " of particular notions within groups, and variation in individuals' topical knowledge across groups. The ease and accuracy of freelist interviewing, or freelisting, makes it ideal for collecting data on health knowledge and beliefs from relatively large samples. Successful freelisting requires researchers to break the research topic into honed categories. Research participants presented with broad prompts tend to " unpack " mental subcategories and may omit (forget) common items or categories. Researchers should find subdomains to present individually for participants to unpack in separate smaller freelists. Researchers may focus the freelist prompts through successive freelisting, pile sorts, or focus group-interviews. Written freelisting among literate populations allows for rapid data collection, possibly from multiple individuals simultaneously. Among nonliterate peoples, using oral freelists remains a relatively rapid method; however, interviewers must prevent bystanders from " contaminating " individual interviewees' lists. Researchers should cross-check freelist responses with informal methods as much as practicable to contextualize and understand the references therein. With proper attention to detail, freelisting can amass high quality data on people's medical understanding, attitudes, and behaviors

Risk, Reciprocity and Solidarity: The Moral Economy of Fishing in Trincomalee, Sri Lanka

This study explores the role of religious values at the individual and community levels in relation to the moral economy of fishing in Sri Lanka. Comparing daily interactions among Sinhala Buddhist, Tamil Hindu and Muslim fishers in the eastern coastal district of Trincomalee, this chapter explores how fishers choose and mix different value systems to justify various decisions and behaviours. Both religious and fishing motivations are examined. Our findings indicate that people take advantage of the malleable nature of seemingly static religious doctrine to mix, match and choose from different religions to suit the current need and the occasion. Religious beliefs and ideologies also create and sustain socio-political differences, which are further constructed by macro-level political discourses. This chapter also analyses how discourses on religious identity play out in everyday life and how economic rivalries over fishing resources spill over into—or are reinforced by—religious and ethnic tensions in the post-war context. In terms of fisheries governance, the analysis shows that managers need to recognise and understand the role of religion and value systems in shaping the moral economy of fishing, as well as the processes by which religious beliefs and ideology can create and sustain social cleavages