Alu elements are a family of interspersed repeats that have mobilized throughout primate genomes by retroposition from a few "master" genes. Among the 500,000 Alu elements in the human genome are members of the human-specific subfamily that are not fixed in the human species; that is, not all chromosomes carry an Alu element at a particular locus. Four such polymorphic human-specific Alu insertions were analyzed by a rapid, PCR-based assay that uses primers that flank the insertion point to determine genotypes based on the presence or absence ofthe Alu element. These four polymorphic Alu insertions were shown to be absent from the genomes of a number of nonhuman primates, consistent with their arising as human genetic polymorphisms sometime after the human/African ape divergence. Analysis of 664 unrelated individuals from 16 population groups from around the world revealed substantial levels of variation within population groups and significant genetic differentiation among groups. No significant associations were found among the four loci, consistent with their location on different chromosomes. A maxnmum-likelihood tree of population relationships showed four major groupings consisting of Africa, Europe, Asia/Americas, and Australia/New Guinea, which is concordant with similar trees based on other loci. A particularly useful feature of the polymorphic Alu insertions is that the ancestral state is known to be the absence of the Alu element, and the presence of the Alu element at a particular chromosomal site reflects a single, unique event in human evolution. A hypothetical ancestral group can then be included in the tree analysis, with the frequency of each insertion set to zero. The ancestral group connected to the maximum-likelihood tree within the African branch, which suggests an African origin of these polymorphic Alu insertions. These data are concordant with other diverse data sets, which lends further support to the recent African origin hypothesis for modern humans. Polymorphic Alu insertions represent a source of genetic variation for studying human population structure and evolution.'

Background: Chagas Disease is a neglected tropical disease caused by the protozoan Trypanosoma cruzi, with some of the most serious manifestations affecting the cardiovascular system. It is a chronic, stigmatizing condition, closely associated with poverty and affecting close to 6 million people globally. Although historically the disease was limited to endemic areas of Latin America recent years have seen an increasing global spread. In addition to the morbidity and mortality associated with the disease, the social and economic burdens on individuals and society are substantial. Often called the 'silent killer', Chagas disease is characterized by a long, asymptomatic phase in affected indivi duals. A pproximately 30% then go on develop chronic Chagas cardiomyopathy and other serious cardiac complications such as stroke, rhythm disturbances and severe heart failure. Methods: In a collaboration of the World Hearth Federation (WHF) and the Inter-American S ociety of Cardiology (IASC) a writing group consisting of 20 diverse experts on Chagas disease (CD) was convened. The group provided up to date expert knowledge based on their area of expertise. An extensive review of the literature describing obstacles to diagnosis and treatment Echeverría et al: WHF IASC Roadmap on Chagas Disease Art. 26, page 2 of 31 of CD along with proposed solutions was conducted. A survey was sent to all WHF Members and, using snowball sampling to widen the consultation, to a variety of health care professionals working in the CD global health community. The results were analyzed, open comments were reviewed and consolidated, and the findings were incorporated into this document, thus ensuring a consensus representation. Results: The WHF IASC Roadmap on Chagas Disease offers a comprehensive summary of current knowledge on prevention, diagnosis and management of the disease. In providing an analysis of 'roadblocks' in access to comprehensive care for Chagas disease patients, the document serves as a framework from which strategies for implementation such as national plans can be formulated. Several dimensions are considered in the analysis: healthcare system capabilities, governance, financing, community awareness and advocacy. Conclusion: The WHF IASC Roadmap proposes strategies and evidence-based solutions for healthcare professionals, health authorities and governments to help overcome the barriers to comprehensive care for Chagas disease patients. This roadmap describes an ideal patient care pathway, and explores the roadblocks along the way, offering potential solutions based on available research and examples in practice. It represents a call to action to decision-makers and health care professionals to step up efforts to eradicate Chagas disease.

As the global COVID-19 pandemic advances, it increasingly impacts those vulnerable populations who already bear a heavy burden of neglected tropical disease. Chagas disease (CD), a neglected parasitic infection, is of particular concern because of its potential to cause cardiac, gastrointestinal, and other complications which could increase susceptibility to COVID-19. The over one million people worldwide with chronic Chagas cardiomyopathy require special consideration because of COVID-19’s potential impact on the heart, yet the pandemic also affects treatment provision to people with acute or chronic indeterminate CD. In this document, a follow-up to the WHF-IASC Roadmap on CD, we assess the implications of coinfection with SARS-CoV-2 and Trypanosoma cruzi , the etiological agent of CD. Based on the limited evidence available, we provide preliminary guidance for testing, treatment, and management of patients affected by both diseases, while highlighting emerging healthcare access challenges and future research needs.

Transposable and interspersed repetitive elements (TIREs) are ubiquitous features of both prokaryotic and eukaryotic genomes. However, controversy has arisen as to whether these sequences represent useless 'selfish' DNA elements, with no cellular function, as opposed to useful genetic units. In this review, we selected two insect species, the Dipteran Drosophila and the Lepidopteran Bombyx mori (the silkmoth), in an attempt to resolve this debate. These two species were selected on the basis of the special interest that our laboratory has had over the years in Bombyx with its well known molecular and developmental biology, and the wealth of genetic data that exist for Drosophila. In addition, these two species represent contrasting repetitive element types and patterns of distribution. On one hand, Bombyx exhibits the short interspersion pattern in which Alu-like TIREs predominate while Drosophila possesses the long interspersion pattern in which retroviral-like TIREs are prevalent. In Bombyx, the main TIRE family is Bm-1 while the Drosophila group contains predominantly copia-like elements, non-LTR retroposons, bacterial-type retroposons and fold-back transposable elements sequences. Our analysis of the information revealed highly non-random patterns of both TIRE biology and evolution, more indicative of these sequences acting as genomic symbionts under cellular regulation rather than useless or selfish junk DNA. In addition, we extended our analysis of potential TIRE functionality to what is known from other eukaryotic systems. From this study, it became apparent that these DNA elements may have originated as innocuous or selfish sequences and then adopted functions. The mechanism for this conversion from non-functionality to specific roles is a process of coevolution between the repetitive element and other cellular DNA often times in close physical proximity. The resulting interdependence between repetitive elements and other cellular sequences restrict the number of evolutionarily successful mutational changes for a given function or cistron. This mutual limitation is what we call genome canalization. Well documented examples are discussed to support this hypothesis and a mechanistic model is presented for how such genomic canalization can occur. Also proposed are empirical studies which would support or invalidate aspects of this hypothesis.