Local Admixture of Amplified and Diversified Secreted Pathogenesis Determinants Shapes Mosaic \u3cem\u3eToxoplasma gondii\u3c/em\u3e Genomes

Toxoplasma gondii is among the most prevalent parasites worldwide, infecting many wild and domestic animals and causing zoonotic infections in humans. T. gondii differs substantially in its broad distribution from closely related parasites that typically have narrow, specialized host ranges. To elucidate the genetic basis for these differences, we compared the genomes of 62 globally distributed T. gondii isolates to several closely related coccidian parasites. Our findings reveal that tandem amplification and diversification of secretory pathogenesis determinants is the primary feature that distinguishes the closely related genomes of these biologically diverse parasites. We further show that the unusual population structure of T. gondii is characterized by clade-specific inheritance of large conserved haploblocks that are significantly enriched in tandemly clustered secretory pathogenesis determinants. The shared inheritance of these conserved haploblocks, which show a different ancestry than the genome as a whole, may thus influence transmission, host range and pathogenicity

Of skilled migration, brain drains and policy responses

Developed countries are increasingly trying to attract skilled migrants, rarely giving any consideration to the impact that this migration might have on countries of origin. The debate on the "brain drain" is not new but it has taken on greater urgency in the context of a globalizing economy and ageing societies and this article reviews the evidence over time and space. It examines opposing interpretations of the impact of the skilled from countries of origin and goes on to examine the particular case of the migration of health professionals. Health workers are seen to be key to achieving basic welfare objectives in any country and their loss may be critical to countries of origin. Hence, the movement of health professionals may be central to any understanding of a brain drain. However, the case for a brain drain, even in this sector, is not straightforward. Specific country and place of origin of the skilled, place of training, appropriateness of training, fit of skills to needs, and the role of return and inmigration of health professionals all need to be taken into consideration. The article examines the case for a two-tiered health training system, one for global markets and the other for local markets. Retention and return of the skilled are examined through the potential for outsourcing in both education and health care. The article concludes with an examination of policy approaches towards skilled migration and offers pointers towards a more balanced and integrated approach by placing the emphasis on development rather than control of migrants