Deconstructing Eurocentrism in skin pigmentation research via the incorporation of diverse populations and theoretical perspectives.

The evolution of skin pigmentation has been shaped by numerous biological and cultural shifts throughout human history. Vitamin D is considered a driver of depigmentation evolution in humans, given the deleterious health effects associated with vitamin D deficiency, which is often shaped by cultural factors. New advancements in genomics and epigenomics have opened the door to a deeper exploration of skin pigmentation evolution in both contemporary and ancient populations. Data from ancient Europeans has offered great context to the spread of depigmentation alleles via the evaluation of migration events and cultural shifts that occurred during the Neolithic. However, novel insights can further be gained via the inclusion of diverse ancient and contemporary populations. Here we present on how potential biases and limitations in skin pigmentation research can be overcome with the integration of interdisciplinary data that includes both cultural and biological elements, which have shaped the evolutionary history of skin pigmentation in humans.

Genomic evidence for ancient human migration routes along South America's Atlantic coast.

An increasing body of archaeological and genomic evidence has hinted at a complex settlement process of the Americas by humans. This is especially true for South America, where unexpected ancestral signals have raised perplexing scenarios for the early migrations into different regions of the continent. Here, we present ancient human genomes from the archaeologically rich Northeast Brazil and compare them to ancient and present-day genomic data. We find a distinct relationship between ancient genomes from Northeast Brazil, Lagoa Santa, Uruguay and Panama, representing evidence for ancient migration routes along South America's Atlantic coast. To further add to the existing complexity, we also detect greater Denisovan than Neanderthal ancestry in ancient Uruguay and Panama individuals. Moreover, we find a strong Australasian signal in an ancient genome from Panama. This work sheds light on the deep demographic history of eastern South America and presents a starting point for future fine-scale investigations on the regional level.

Patterns of Genetic Coding Variation in a Native American Population before and after European Contact.

The effects of European colonization on the genomes of Native Americans may have produced excesses of potentially deleterious features, mainly due to the severe reductions in population size and corresponding losses of genetic diversity. This assumption, however, neither considers actual genomic patterns that existed before colonization nor does it adequately capture the effects of admixture. In this study, we analyze the whole-exome sequences of modern and ancient individuals from a Northwest Coast First Nation, with a demographic history similar to other indigenous populations from the Americas. We show that in approximately ten generations from initial European contact, the modern individuals exhibit reduced levels of novel and low-frequency variants, a lower proportion of potentially deleterious alleles, and decreased heterozygosity when compared to their ancestors. This pattern can be explained by a dramatic population decline, resulting in the loss of potentially damaging low-frequency variants, and subsequent admixture. We also find evidence that the indigenous population was on a steady decline in effective population size for several thousand years before contact, which emphasizes regional demography over the common conception of a uniform expansion after entry into the Americas. This study examines the genomic consequences of colonialism on an indigenous group and describes the continuing role of gene flow among modern populations.

Ancient individuals from the North American Northwest Coast reveal 10,000 years of regional genetic continuity.

Recent genomic studies of both ancient and modern indigenous people of the Americas have shed light on the demographic processes involved during the first peopling. The Pacific Northwest Coast proves an intriguing focus for these studies because of its association with coastal migration models and genetic ancestral patterns that are difficult to reconcile with modern DNA alone. Here, we report the low-coverage genome sequence of an ancient individual known as "Shuká Káa" ("Man Ahead of Us") recovered from the On Your Knees Cave (OYKC) in southeastern Alaska (archaeological site 49-PET-408). The human remains date to ∼10,300 calendar (cal) y B.P. We also analyze low-coverage genomes of three more recent individuals from the nearby coast of British Columbia dating from ∼6,075 to 1,750 cal y B.P. From the resulting time series of genetic data, we show that the Pacific Northwest Coast exhibits genetic continuity for at least the past 10,300 cal y B.P. We also infer that population structure existed in the late Pleistocene of North America with Shuká Káa on a different ancestral line compared with other North American individuals from the late Pleistocene or early Holocene (i.e., Anzick-1 and Kennewick Man). Despite regional shifts in mtDNA haplogroups, we conclude from individuals sampled through time that people of the northern Northwest Coast belong to an early genetic lineage that may stem from a late Pleistocene coastal migration into the Americas.

Successful extraction and PCR amplification of Giardia DNA from formalin-fixed stool samples.

Extracting genomic DNA of pathogenic agents from formalin-fixed specimens is inherently difficult. Storage of samples in formalin results in nucleic acid cross-linking and DNA fragmentation. In this study, DNA was extracted from 45 Giardia-positive stool samples stored in formalin and subjected to PCR amplification targeting the triose phosphate isomerase (tpi), beta gardin (bg) and glutamate dehydrogenase (gdh) genes. Samples were rehydrated by using a descending alcohol series before DNA extraction using a commercial kit. This was followed by EDTA-mediated inhibition of DNase activity and prolonged treatment with proteinase K to digest contaminating proteins. DNA was amplified at rates of 64.4% (29/45) at the tpi, 40% (18/45) at the bg and 20% (9/45) at the gdh loci as seen on nested PCR. DNA quality was subsequently tested in a genotyping experiment which produced high-quality sequences at the tpi (41.2%; 12/29) bg (50%; 9/18), and gdh (22.2%; 2/9) loci and enabled differentiation of Giardia strains at the subtype level. The modified extraction protocol was effective at removing inhibitors and reversing cross-linking of DNA. However, PCR amplification was limited to short fragments of DNA which resulted in highest success rate on amplification of the shortest (334 bp) gene fragment tested.

Dysregulated TGF-ß Production Underlies the Age-Related Vulnerability to Chikungunya Virus.

Chikungunya virus (CHIKV) is a re-emerging global pathogen with pandemic potential, which causes fever, rash and debilitating arthralgia. Older adults over 65 years are particularly susceptible to severe and chronic CHIKV disease (CHIKVD), accounting for >90% of all CHIKV-related deaths. There are currently no approved vaccines or antiviral treatments available to limit chronic CHIKVD. Here we show that in old mice excessive, dysregulated TGFß production during acute infection leads to a reduced immune response and subsequent chronic disease. Humans suffering from CHIKV infection also exhibited high TGFß levels and a pronounced age-related defect in neutralizing anti-CHIKV antibody production. In vivo reduction of TGFß levels minimized acute joint swelling, restored neutralizing antibody production and diminished chronic joint pathology in old mice. This study identifies increased and dysregulated TGFß secretion as one key mechanism contributing to the age-related loss of protective anti-CHIKV-immunity leading to chronic CHIKVD.

Multilocus sequence analysis of Giardia spp. isolated from patients with diarrhea in Austria.

Giardia duodenalis is a protozoan parasite causing intestinal infections in a wide range of mammals. Two distinct assemblages, A and B, infect humans predominantly; however, both are believed to be generally zoonotic. Giardia strains associated with infections in Austria have not been investigated at the molecular level. In this study, 65 human stool samples microscopically positive for Giardia spp. were subjected to DNA isolation and nested PCR targeting fragments of the glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi), and beta-gardin (bg) genes. A total of 52 samples were successfully analyzed using PCR and DNA sequencing. Assemblage B was detected most frequently and accounted for 65.4% (34/52) of infections, while Assemblage A accounted for 34.6% (18/52). There was a high level of genetic diversity among the isolates with 46.2% designated as sub-assemblage BIV (24/52), 25% sub-assemblage AII (13/52), 19.2% sub-assemblage BIII (10/52), and 9.6% sub-assemblage AI (5/52). No mixed infections were detected. The results suggest that the majority of infections were imported and that endemic anthroponotic transmission plays a minor role in Austria.

Molecular epidemiology and multilocus sequence analysis of potentially zoonotic Giardia spp. from humans and dogs in Jamaica.

Giardia spp. are the causative agents of intestinal infections in a wide variety of mammals including humans and companion animals. Dogs may be reservoirs of zoonotic Giardia spp.; however, the potential for transmission between dogs and humans in Jamaica has not been studied. Conventional PCR was used to screen 285 human and 225 dog stool samples for Giardia targeting the SSU rDNA gene followed by multilocus sequencing of the triosephosphate isomerase (tpi), glutamate dehydrogenase (gdh), and ß-giardin (bg) genes. Prevalence of human infections based on PCR was 6.7 % (19/285) and canine infections 19.6 % (44/225). Nested PCR conducted on all 63 positive samples revealed the exclusive presence of assemblage A in both humans and dogs. Sub-assemblage A-II was responsible for 79.0 % (15/19) and 70.5 % (31/44) of the infections in humans and dogs, respectively, while sub-assemblage A-I was identified at a rate of 15.8 % (3/19) and 29.5 % (13/44) in humans and dogs, respectively. The predominance of a single circulating assemblage among both humans and dogs in Jamaica suggests possible zoonotic transmission of Giardia infections.

The performance of the SD BIOLINE Dengue DUO® rapid immunochromatographic test kit for the detection of NS1 antigen, IgM and IgG antibodies during a dengue type 1 epidemic in Jamaica.

BACKGROUND: Dengue is an important mosquito-borne viral infection that affects millions of persons worldwide. Early diagnosis is necessary to effect appropriate management and decrease mortality. Immunochromatographic tests are advantageous in producing dengue test results within 30 min but these results should be sensitive and specific. In this study we evaluated the diagnostic performance of the SD BIOLINE Dengue DUO® rapid immunochromatographic test kit. A panel of 309 dengue and 30 non-dengue single serum samples characterized by using reference enzyme-linked immunosorbent assays (ELISAs) was used. These samples were received in the virology laboratory for routine testing during a dengue type 1 outbreak between October to December, 2012. RESULTS: The overall diagnostic sensitivities of the SD BIOLINE Dengue DUO® rapid testfor IgM, IgG and NSI were 49.3% (95% CI: 41.3-57.4), 39.1% (95% CI: 33.3-45.2) and 90% (95% CI: 82.1-94.7), respectively. The IgM and IgG detection rates were significantly lower than that of the NSI (p < 0.001). However the combination of the IgM detection with NS1 detection or both NS1 and IgG resulted in a significant (p < 0.001) increase in sensitivity to 97.5% (95 % CI: 92.9-99.2) and 98.9% (95 % CI: 96.0-99.7), respectively. These higher sensitivities were achieved without any decrease in specificities. CONCLUSIONS: This study revealed that combining two or more parameters of the SD BIOLINE Dengue DUO® rapid kit significantly improved the sensitivity of diagnosis of dengue virus infection and supports its usefulness in the Jamaican setting.

Isolation and genotyping of acanthamoeba strains from soil sources from Jamaica, West Indies.

Acanthamoeba spp. are opportunistic pathogens that are ubiquitous in nature. Many species of this genus are responsible for a fatal encephalitis and keratitis in humans and other animals. Seventy-two soil samples were collected from the parishes across Jamaica and assessed for the presence of Acanthamoeba spp. Cultivation was carried out on non-nutrient agar plates seeded with heat killed Escherichia coli. PCR and sequencing of the DF3 region were carried out in order to genotype the isolated strains of Acanthamoeba. Thermotolerance and osmotolerance assays were utilized to investigate the pathogenic potential of the Acanthamoeba isolates. Acanthamoeba spp. was isolated from 63.9% of soil samples. Sequencing of the DF3 region of the 18S rDNA resulted in the identification of genotypes T4, T5, and T11. T4 genotype was most frequently isolated. Most isolates were thermotolerant or both thermotolerant and osmotolerant, indicating that they may present the potential to cause disease in humans and other animals.

Isolation and molecular characterization of Acanthamoeba genotypes in recreational and domestic water sources from Jamaica, West Indies.

Free living amoebae (FLA) are amphizoic protozoa that are ubiquitous in nature. Infection with FLA may result in neurological, ocular and skin infections. Exposure to Acanthamoeba occurs frequently through water contact and knowledge of the presence of the organisms in water sources is important in understanding transmission dynamics. The distribution of Acanthamoeba was studied in recreational and domestic water samples collected from across Jamaica. Morphological assessment and polymerase chain reaction revealed Acanthamoeba spp. isolates in 50.6% (42/83) and 17.3% (14/81) of recreational and domestic water, respectively. Sequencing of the DF3 region of the 18S rDNA resulted in the identification of genotypes T3, T4, T5, T10 and T11 corresponding to Acanthamoeba spp: A. griffini, A. triangularis, A. lenticulata, A. culbertsoni and A. hatchetti. Moreover, T4 was the most frequently isolated genotype in both recreational and domestic water. Thermotolerance and osmotolerance assays indicated that most isolates were potentially pathogenic. This is the first report of T3 and T10 genotypes in the Caribbean and the first report of these Acanthamoeba spp. in Jamaican waters. The study shows that there is potential risk of infection to contact wearers who practise poor lens care. Further, Acanthamoeba should be considered as a cause of neurological infections in Jamaica.

Isolation and characterization of Acanthamoeba strains from soil samples in Gran Canaria, Canary Islands, Spain.

Free-living Amoebae of Acanthamoeba genus include non-pathogenic and pathogenic strains that are currently classified in 18 different genotypes, T1-T18. In this study, a survey was carried out to evaluate the presence of Acanthamoeba strains in soil samples collected between 2012 and 2013 in Gran Canaria Island, Canary Islands, Spain. Samples were inoculated onto non-nutrient agar (NNA) plates and were checked for the presence of Acanthamoeba. Identification of Acanthamoeba strains was based on the morphology of the cyst and trophozoite forms. Subsequently, positive samples were cloned for their molecular characterization at the genotype level by sequencing the DF3 region located in the 18S rDNA gene of Acanthamoeba as previously described. Sequencing results revealed the presence of T2, T5 and T4 genotypes within the studied samples. To the best of our knowledge, this is the first report demonstrating the presence of Acanthamoeba in Gran Canaria Island and the first study at the genotype level in the Canary Islands.

Grandmotherhood is associated with reduced OXTR DNA methylation.

In mammals, both parental and alloparental care are associated with increased brain oxytocin signaling. Grandmothers are important alloparents in many human families. Based on animal model research showing that peripheral Oxtr methylation is associated with Oxtr expression in the nucleus accumbens, we investigated whether grandmaternal caregiving is associated with lower peripheral OXTR methylation. Results reveal several regions within OXTR where grandmothers have lower DNA methylation compared with non-grandmother controls, and no regions where grandmothers have higher OXTR DNA methylation. Among grandmothers, OXTR methylation was most strongly correlated with the grandmother's assessment of the degree of positive feelings between her and the grandchild, which in turn predicted caregiving engagement. Although there was little evidence that grandmaternal OXTR methylation modulated grandmaternal neural responses to viewing photos of the grandchild within brain regions involved in caregiving motivation, it was negatively correlated with the neural response to an unknown grandchild. Thus, while OT signaling may not be essential for activating grandmaternal brain reward systems in our low-stress experimental context, it may support caregiving motivation towards unrelated children. Future longitudinal research should determine whether the transition to grandmotherhood is associated with a reduction in OXTR methylation.

Building Research Capacity in Low- and Middle-Income Countries and Pandemic Preparedness: Lessons Learned and Future Directions.

Research capacity is a critical component of pandemic preparedness, as highlighted by the challenges faced during the Ebola outbreak in West Africa. Recent global initiatives, such as the Research & Development Task Force of the Global Health Security Agenda and the World Health Assembly's resolution on strengthening clinical trials, emphasize the need for robust research capabilities. This Perspective discusses the experiences of leaders in infectious disease research and capacity building in low- and middle-income countries, focusing on Colombia, Jamaica, and Pakistan. These case studies underscore the importance of collaborative efforts, interdisciplinary training, and global partnerships in pandemic response. The experiences highlight the necessity for rapid pathogen identification, capacity for genomic sequencing, and proactive engagement with policymakers. Challenges faced, including the shortage of trained staff and reliance on imported reagents, emphasize the ongoing need for building research capacity.

Genomic analyses correspond with deep persistence of peoples of Blackfoot Confederacy from glacial times.

Mutually beneficial partnerships between genomics researchers and North American Indigenous Nations are rare yet becoming more common. Here, we present one such partnership that provides insight into the peopling of the Americas and furnishes another line of evidence that can be used to further treaty and Indigenous rights. We show that the genomics of sampled individuals from the Blackfoot Confederacy belong to a previously undescribed ancient lineage that diverged from other genomic lineages in the Americas in Late Pleistocene times. Using multiple complementary forms of knowledge, we provide a scenario for Blackfoot population history that fits with oral tradition and provides a plausible model for the evolutionary process of the peopling of the Americas.

Spatiotemporal fluctuations of population structure in the Americas revealed by a meta-analysis of the first decade of archaeogenomes.

Objectives: Since 2010, genome-wide data from hundreds of ancient Native Americans have contributed to the understanding of Americas' prehistory. However, these samples have never been studied as a single dataset, and distinct relationships among themselves and with present-day populations may have never come to light. Here, we reassess genomic diversity and population structure of 223 ancient Native Americans published between 2010 and 2019. Materials and Methods: The genomic data from ancient Americas was merged with a worldwide reference panel of 278 present-day genomes from the Simons Genome Diversity Project and then analyzed through ADMIXTURE, D-statistics, PCA, t-SNE, and UMAP. Results: We find largely similar population structures in ancient and present-day Americas. However, the population structure of contemporary Native Americans, traced here to at least 10,000 years before present, is noticeably less diverse than their ancient counterparts, a possible outcome of the European contact. Additionally, in the past there were greater levels of population structure in North than in South America, except for ancient Brazil, which harbors comparatively high degrees of structure. Moreover, we find a component of genetic ancestry in the ancient dataset that is closely related to that of present-day Oceanic populations but does not correspond to the previously reported Australasian signal. Lastly, we report an expansion of the Ancient Beringian ancestry, previously reported for only one sample. Discussion: Overall, our findings support a complex scenario for the settlement of the Americas, accommodating the occurrence of founder effects and the emergence of ancestral mixing events at the regional level.

Seroprevalence and Genotype Diversity of Hepatitis C Virus in the Caribbean-A Review.

Hepatitis C (HCV) continues to present a global public health challenge, with no vaccine available for prevention. Despite the availability of direct-acting antivirals (DAAs) to cure HCV, it remains prevalent in many regions including the Caribbean. As efforts are made to eliminate HCV from the region, existing barriers, such as the high cost of DAAs and lack of an established database of HCV cases within the Caribbean, must be addressed. This review seeks to assess epidemiologic trends (seroprevalence and genotypic diversity) of HCV in the Caribbean and identify gaps in surveillance of the disease. The literature for the period 1 January 2005 to October 2022 was reviewed to gather country-specific data on HCV across the Caribbean. References were identified through indexed journals accessed through established databases using the following keywords: Caribbean, genotype distribution, and general epidemiologic characteristics. The usage pattern of HCV drugs was determined from information obtained from pharmacists across the Caribbean including Jamaica. The prevalence of HCV in the Caribbean was 1.5%; the region should therefore be considered an area of moderate HCV prevalence. The prevalence of HCV among intravenous drug users (21.9-58.8%), persons living with HIV/AIDS (0.8 to 58.5%), prisoners (32.8-64%), and men who have sex with men (MSM) (0.8-6.9%) was generally higher than in the general population (0.8-2.3%). Genotype 1 (83%) was most prevalent followed by genotypes 2 (7.2%) and 3 (2.1%), respectively. Less than 50% of countries in the Caribbean have reliable or well-curated surveillance data on HCV. Drugs currently being used for treatment of HCV infections across the Caribbean include Epclusa (sofosbuvir/velpatasvir) and Harvoni (ledipasvir/sofosbuvir). Some of these drugs are only available in the private sector and are sourced externally whenever needed. While trends point to a potentially higher prevalence of HCV, it will require well-designed random surveys to obtain better estimates of the infection seroprevalence, supported by strong public health laboratory systems. DAAs that are pan-genotypic should translate into treatments that are affordable, accessible, and available to improve cure rates and reduce the HCV burden in the population.

Genomic evidence for adaptation to tuberculosis in the Andes before European contact.

Most studies focusing on human high-altitude adaptation in the Andean highlands have thus far been focused on Peruvian populations. We present high-coverage whole genomes from Indigenous people living in the Ecuadorian highlands and perform multi-method scans to detect positive natural selection. We identified regions of the genome that show signals of strong selection to both cardiovascular and hypoxia pathways, which are distinct from those uncovered in Peruvian populations. However, the strongest signals of selection were related to regions of the genome that are involved in immune function related to tuberculosis. Given our estimated timing of this selection event, the Indigenous people of Ecuador may have adapted to Mycobacterium tuberculosis thousands of years before the arrival of Europeans. Furthermore, we detect a population collapse that coincides with the arrival of Europeans, which is more severe than other regions of the Andes, suggesting differing effects of contact across high-altitude populations.

The multifaceted genomic history of Ashaninka from Amazonian Peru.

Despite its crucial location, the western side of Amazonia between the Andes and the source(s) of the Amazon River is still understudied from a genomic and archaeogenomic point of view, albeit possibly harboring essential information to clarify the complex genetic history of local Indigenous groups and their interactions with nearby regions,1,2,3,4,5,6,7,8 including central America and the Caribbean.9,10,11,12 Focusing on this key region, we analyzed the genome-wide profiles of 51 Ashaninka individuals from Amazonian Peru, observing an unexpected extent of genomic variation. We identified at least two Ashaninka subgroups with distinctive genomic makeups, which were differentially shaped by the degree and timing of external admixtures, especially with the Indigenous groups from the Andes and the Pacific coast. On a continental scale, Ashaninka ancestors probably derived from a south-north migration of Indigenous groups moving into the Amazonian rainforest from a southeastern area with contributions from the Southern Cone and the Atlantic coast. These ancestral populations diversified in the variegated geographic regions of interior South America, on the eastern side of the Andes, differentially interacting with surrounding coastal groups. In this complex scenario, we also revealed strict connections between the ancestors of present-day Ashaninka, who belong to the Arawakan language family,13 and those Indigenous groups that moved further north into the Caribbean, contributing to the early Ceramic (Saladoid) tradition in the islands.14,15.

Increasing Effectiveness and Equity in Strengthening Health Research Capacity Using Data and Metrics: Recent Advances of the ESSENCE Mechanism.

Background: The ESSENCE on Health Research initiative established a Working Group on Review of Investments in 2018 to improve coordination and collaboration among funders of health research capacity strengthening. The Working Group comprises more than a dozen ESSENCE members, including diverse representation by geography, country income level, the public sector, and philanthropy. Objective: The overall goal of the Working Group is increased research on national health priorities as well as improved pandemic preparedness, and, ultimately, fewer countries with very limited research capacity. Methods: We developed a basic set of metrics for national health research capacity, assessed different models of coordination and collaboration, took a deeper dive into eight countries to characterize their national research capacity, and began to identify opportunities to better coordinate our investments. In this article, we summarize the presentations, discussions, and outcomes of our second annual (virtual) meeting, which had more than 100 participants representing funders, researchers, and other stakeholders from higher- and lower-income countries worldwide. Findings and conclusions: Presentations on the first day included the keynote speaker, Dr. Soumya Swaminathan, chief scientist of the World Health Organization (WHO), and updates on data and metrics for research capacity, which are critical to establish targets, road maps, and budgets. The second day focused on improving collaboration and coordination among funders and other stakeholders, the potential return on investment for health research, ongoing work to increase coordination at the country level, and examples of research capacity strengthening efforts in diverse health research areas from around the world. We concluded that an intentional data- and metric-driven approach to health research capacity strengthening, emphasizing coordination among funders, local leadership, and equitable partnerships and allocation of resources, will enhance the health systems of resource-poor countries as well as the world's pandemic preparedness.