生活習慣病とgenome-wide association study

Sexual reproduction is an ancient feature of life on earth, and the familiar X and Y chromo- somes in humans and other model species have led to the impression that sex determination mecha- nisms are old and conserved. In fact, males and females are deter- mined by diverse mechanisms that evolve rapidly in many taxa. Yet this diversity in primary sex-deter- mining signals is coupled with conserved molecular pathways that trigger male or female develop- ment. Conflicting selection on dif- ferent parts of the genome and on the two sexes may drive many of these transitions, but few systems with rapid turnover of sex determi- nation mechanisms have been rig- orously studied. Here we survey our current understanding of how and why sex determination evolves in animals and plants and identify important gaps in our knowledge that present exciting research op- portunities to characterize the evo- lutionary forces and molecular pathways underlying the evolution of sex determination.

/pdf/sex-determination-why-so-many-ways-of-doing-it-ivb1ovfz8c.pdf

Sex Determination: Why So Many Ways of Doing It?

Genetics of bipolar disorder

There has been a significant investment in research to define exposures and potential hazards of pharmaceuticals in freshwater and terrestrial ecosystems. A substantial number of integrated environmental risk assessments have been developed in Europe, North America and many other regions for these situations. In contrast, comparatively few empirical studies have been conducted for human and veterinary pharmaceuticals that are likely to enter coastal and marine ecosystems. This is a critical knowledge gap given the significant increase in coastal human populations around the globe and the growth of coastal megacities, together with the increasing importance of coastal aquaculture around the world. There is increasing evidence that pharmaceuticals are present and are impacting on marine and coastal environments. This paper reviews the sources, impacts and concentrations of pharmaceuticals in marine and coastal environments to identify knowledge gaps and suggests focused case studies as a priority for future research.

https://royalsocietypublishing.org/doi/pdf/10.1098/rstb.2013.0572

Sources, impacts and trends of pharmaceuticals in the marine and coastal environment

https://ca.water.usgs.gov/pubs/frambelitz2011pharms.pdf

Occurrence and concentrations of pharmaceutical compounds in groundwater used for public drinking-water supply in California.

Anti-depressants make amphipods see the light.

https://researchportal.port.ac.uk/portal/files/1742950/Bossus_et_al._Aquatic_toxicology_2013_Manuscript_revised.pdf

Behavioural and transcriptional changes in the amphipod Echinogammarus marinus exposed to two antidepressants, fluoxetine and sertraline.

Paramyxean-microsporidian co-infection in amphipods: is the consensus that Microsporidia can feminise their hosts presumptive?

The dysfunction associated with intersexuality in vertebrates and molluscs is often a serious threat to ecosystems. Although poorly understood, crustacean intersexuality is associated with contamination and includes forms linked to increased sex-ratio distorting parasites at polluted sites. Despite the importance of crustaceans for monitoring vulnerable aquatic habitats, little is known about the molecular basis of this abnormal sexual differentiation and any associated sexual dysfunction. To increase the relevance of crustaceans to environmental toxicologists, we comprehensively analyzed gene expression in amphipods presenting parasite- and nonparasite-associated intersexuality. Our findings reveal existing vertebrate biomarkers of feminization should not be applied to crustaceans, as orthologous genes are not induced in feminized amphipods. Furthermore, in contrast to vertebrates, where feminization and intersexuality is often associated with deleterious demasculinization, we find males maintain masculinity even when unambiguously feminized. This reveals a considerable regulatory separation of the gene pathways responsible for male and female characteristics and demonstrates that evidence of feminization (even if detected with appropriate biomarkers) is not a proxy for demasculinization in crustaceans. This study has also produced a comprehensive spectrum of potential molecular biomarkers that, when combined with our new molecular understanding, will greatly facilitate the use of crustaceans to monitor aquatic habitats.

/pdf/crustacean-intersexuality-is-feminization-without-33nsew2ir8.pdf

Crustacean intersexuality is feminization without demasculinization: implications for environmental toxicology.

The causes of sex determination in amphipods are believed to be multi-factorial. Sex determination in Echinogammarus marinus (Leach, 1815) has been reported to be linked with feminising parasites. To date, however, no such studies have linked this species with environmental sex determination (ESD). A field study and laboratory breeding experiments were conducted to determine the influence of photoperiod on sex determination. Over the two-year field study, males dominated during August to November, whilst female-biased populations were observed during April to July. A significant linear relationship was observed between photoperiods and sex ratios from the field data. Under laboratory conditions, photoperiod was also shown to be an influential factor in sex determination, with a male bias over a long-day photo regime (61.5 % male broods) and a female biased over a short-day photoperiod regime (43.5 % male broods). Findings suggest that there is some level of ESD present within the species, suggesting considerable plasticity in the sex differentiation pathway.

Yasmin Guler

Papers

Anti-depressants make amphipods see the light.

Behavioural and transcriptional changes in the amphipod Echinogammarus marinus exposed to two antidepressants, fluoxetine and sertraline.

Paramyxean-microsporidian co-infection in amphipods: is the consensus that Microsporidia can feminise their hosts presumptive?

Crustacean intersexuality is feminization without demasculinization: implications for environmental toxicology.

Integrating field and laboratory evidence for environmental sex determination in the amphipod, Echinogammarus marinus