Malaria in a vulnerable population living in quilombo remnant communities in the Brazilian Amazon: a cross-sectional study from 2005-2020.

Quilombo remnant communities are areas officially recognized by the Brazilian government as historical communities founded by formerly enslaved individuals. These communities are mostly located in the endemic areas of malaria in the Brazilian Amazon. We retrospectively described the prevalence of malaria among individuals living in 32 recognized quilombo remnant communities in the Baiao and Oriximina municipalities located in the Para State. The number of malaria cases and the Annual Parasitic Incidence (API) recorded by the Brazilian malaria surveillance system (SIVEP-Malaria) from January 2005 to December 2020 were analyzed. We found that all communities registered at least one case over the 16-year period, the most frequent parasitic species being Plasmodium vivax (76.1%). During this period, 0.44% (4,470/1,008,714) of the malaria cases registered in Para State were reported in these quilombo remnant communities, with frequencies of 10.9% (856/7,859) in Baiao municipality and 39.1% (3,614/9,238) in Oriximina municipality, showing that individuals living in these rural communities are exposed to malaria. These data indicate that effective surveillance requires improved measures to identify malaria transmission among vulnerable populations living in quilombo remnant communities in the Brazilian Amazon.

Association between Polymorphism of Genes IL-1A, NFKB1, PAR1, TP53, and UCP2 and Susceptibility to Non-Small Cell Lung Cancer in the Brazilian Amazon.

Non-small cell lung cancer (NSCLC) accounts for the vast majority of cases of lung neoplasms. It is formed in multiple stages, with interactions between environmental risk factors and individual genetic susceptibility and with genes involved in the immune and inflammatory response paths, cell or genome stability, and metabolism, among others. Our objective was to evaluate the association between five genetic variants (IL-1A, NFKB1, PAR1, TP53, and UCP2) and the development of NSCLC in the Brazilian Amazon. The study included 263 individuals with and without lung cancer. The samples were analyzed for the genetic variants of NFKB1 (rs28362491), PAR1 (rs11267092), TP53 (rs17878362), IL-1A (rs3783553), and UCP2 (INDEL 45-bp), which were genotyped in PCR, followed by an analysis of the fragments, in which we applied a previously developed set of informative ancestral markers. We used a logistic regression model to identify differences in the allele and the genotypic frequencies among individuals and their association with NSCLC. The variables of gender, age, and smoking were controlled in the multivariate analysis to prevent confusion by association. The individuals that were homozygous for the Del/Del of polymorphism NFKB1 (rs28362491) (p = 0.018; OR = 0.332) demonstrate a significant association with NSCLC, which was similar to that observed in the variants of PAR1 (rs11267092) (p = 0.023; OR = 0.471) and TP53 (rs17878362) (p = 0.041; OR = 0.510). Moreover, the individuals with the Ins/Ins genotype of polymorphism IL-1A (rs3783553) demonstrated greater risk for NSCLC (p = 0.033; OR = 2.002), as did the volunteers with the Del/Del of UCP2 (INDEL 45-bp) (p = 0.031; OR = 2.031). The five polymorphisms investigated can contribute towards NSCLC susceptibility in the population of the Brazilian Amazon.

Identification of Genomic Variants Associated with the Risk of Acute Lymphoblastic Leukemia in Native Americans from Brazilian Amazonia.

A number of genomic variants related to native American ancestry may be associated with an increased risk of developing Acute Lymphoblastic Leukemia (ALL), which means that Latin American and hispanic populations from the New World may be relatively susceptible to this disease. However, there has not yet been any comprehensive investigation of the variants associated with susceptibility to ALL in traditional Amerindian populations from Brazilian Amazonia. We investigated the exomes of the 18 principal genes associated with susceptibility to ALL in samples of 64 Amerindians from this region, including cancer-free individuals and patients with ALL. We compared the findings with the data on populations representing five continents available in the 1000 Genomes database. The variation in the allele frequencies found between the different groups was evaluated using Fisher's exact test. The analyses of the exomes of the Brazilian Amerindians identified 125 variants, seven of which were new. The comparison of the allele frequencies between the two Amerindian groups analyzed in the present study (ALL patients vs. cancer-free individuals) identified six variants (rs11515, rs2765997, rs1053454, rs8068981, rs3764342, and rs2304465) that may be associated with susceptibility to ALL. These findings contribute to the identification of genetic variants that represent a potential risk for ALL in Amazonian Amerindian populations and might favor precision oncology measures.

UGT1A1 Gene Polymorphism Contributes as a Risk Factor for Lung Cancer: A Pilot Study with Patients from the Amazon.

Lung cancer is one of the most frequent neoplasms in the world. Because it is a complex disease, its formation occurs in several stages, stemming from interactions between environmental risk factors, such as smoking, and individual genetic susceptibility. Our objective was to investigate associations between a UGT1A1 gene polymorphism (rs8175347) and lung cancer risk in an Amazonian population. This is a pilot study, case-controlled study, which included 276 individuals with cancer and without cancer. The samples were analyzed for polymorphisms of the UGT1A1 gene (rs8175347) and genotyped in PCR, followed by fragment analysis in which we applied a previously developed set of informative ancestral markers. We used logistic regression to identify differences in allelic and genotypic frequencies between individuals. Individuals with the TA7 allele have an increased chance of developing lung adenocarcinoma (p = 0.035; OR: 2.57), as well as those with related genotypes of reduced or low enzymatic activity: TA6/7, TA5/7, and TA7/7 (p = 0.048; OR: 8.41). Individuals with homozygous TA7/7 have an increased chance of developing squamous cell carcinoma of the lung (p = 0.015; OR: 4.08). Polymorphism in the UGT1A1 gene (rs8175347) may contribute as a risk factor for adenocarcinoma and lung squamous cell carcinoma in the population of the Amazon region.

Exome Evaluation of Autism-Associated Genes in Amazon American Populations.

Autism spectrum disorder is a neurodevelopmental disorder, affecting one in 160 children worldwide. The causes of autism are still poorly understood, but research shows the relevance of genetic factors in its pathophysiology, including the CHD8, SCN2A, FOXP1 and SYNGAP1 genes. Information about the genetic influence on various diseases, including autism, in the Amerindian population from Amazon, is still scarce. We investigated 35 variants of the CHD8, SCN2A, FOXP1, and SYNGAP1 gene in Amazonian Amerindians in comparison with publicly available population frequencies from the 1000 Genomes Project database. Our study identified 16 variants in the Amerindian population of the Amazon with frequencies significantly different from the other populations. Among them, the SCN2A (rs17183814, rs75109281, and rs150453735), FOXP1 (rs56850311 and rs939845), and SYNGAP1 (rs9394145 and rs115441992) variants presented higher frequency than all other populations analyzed. In addition, nine variants were found with lower frequency among the Amerindians: CHD8 (rs35057134 and rs10467770), SCN2A (rs3769951, rs2304014, rs1838846, and rs7593568), FOXP1 (rs112773801 and rs56850311), and SYNGAP1 (rs453590). These data show the unique genetic profile of the indigenous population of the Brazilian Amazon. Knowledge of these variants can help to understand the pathophysiology and diagnosis of autism among Amerindians, Brazilians, and in admixed populations that have contributions from this ethnic group.

Correction: Serologically Defined Variations in Malaria Endemicity in Pará State, Brazil.

[This corrects the article DOI: 10.1371/journal.pone.0113357.].

The structure of Brazilian Amazonian gut microbiomes in the process of urbanisation.

Shifts in subsistence strategy among Native American people of the Amazon may be the cause of typically western diseases previously linked to modifications of gut microbial communities. Here, we used 16S ribosomal RNA sequencing to characterise the gut microbiome of 114 rural individuals, namely Xikrin, Suruí and Tupaiú, and urban individuals from Belém city, in the Brazilian Amazon. Our findings show the degree of potential urbanisation occurring in the gut microbiome of rural Amazonian communities characterised by the gradual loss and substitution of taxa associated with rural lifestyles, such as Treponema. Comparisons to worldwide populations indicated that Native American groups are similar to South American agricultural societies and urban groups are comparable to African urban and semi-urban populations. The transitioning profile observed among traditional populations is concerning in light of increasingly urban lifestyles. Lastly, we propose the term "tropical urban" to classify the microbiome of urban populations living in tropical zones.

Isolation of the Arawete and Asurini Indians keeps the tribes free from HTLV infection during 36 years of follow-up.

Arawete and Asurini Indian tribes were revisited after a 36-year follow-up in search of HTLV infections. 46 persons (23 from each tribe) were tested for HTLV-1/2 antibodies and viral DNA. None were positive; this was probably because of their social/cultural isolation from neighboring tribes where HTLV-2c is hyperendemic.

Anthropometric and metabolic profile of a Brazilian Amerindian group: The Xikrin (Mebengôkre).

OBJECTIVES: The purpose of this study was to describe the metabolic and anthropometric profile of the Xikrin (Mebengôkre), an indigenous group. METHODS: A total of 363 subjects (55.1% women) aged 18 years or older were evaluated. The variables analyzed were age, body weight and height, waist circumference, blood pressure, fasting blood glucose, triglyceride level, and total cholesterol level. RESULTS: A high prevalence of obesity (36.5%) and central obesity (88.1%), mainly among women (46.9% and 96.2%, respectively), was found among the Xikrin (Mebengôkre). Impaired fasting glycemia and diabetes were found in 4.5% and 3.8% of adults, respectively. Twenty-one percent of adults had dyslipidemia and 9.3% had hypertension. CONCLUSIONS: The high prevalence of excess weight (overweight and obesity) and central obesity, especially in women, was the most significant finding of this study among the Xikrin (Mebengôkre).

Distribution of allelic and genotypic frequencies of IL1A, IL4, NFKB1 and PAR1 variants in Native American, African, European and Brazilian populations.

BACKGROUND: The inflammatory response plays a key role at different stages of cancer development. Allelic variants of the interleukin 1A (IL1A), interleukin 4 (IL4), nuclear factor kappa B1 (NFKB1) and protease-activated receptor 1 (PAR1) genes may influence not only the inflammatory response but also susceptibility to cancer development. Among major ethnic or continental groups, these polymorphic variants present different allelic frequencies. In admixed populations, such as the Brazilian population, data on distribution of these polymorphisms are limited. Here, we collected samples of cancer-free individuals from the north, northeast, midwest, south and southeast regions of Brazil and from the three main groups that gave rise to the Brazilian population: Native Americans from the Brazilian Amazon, Africans and Europeans. We describe the allelic distributions of four IL1A (rs3783553), IL4 (rs79071878), NFKB1 (rs28362491) and PAR1 (rs11267092) gene polymorphisms, which the literature describes as polymorphisms with a risk of cancer or worse prognosis for cancer. RESULTS: The genotypic distribution of the four polymorphisms was statistically distinct between Native Americans, Africans and Europeans. For the allelic frequency of these polymorphisms, the Native American population was the most distinct among the three parental populations, and it included the greatest number of alleles with a risk of cancer or worse prognosis for cancer. The PAR1 gene polymorphism allelic distribution was similar among all Brazilian regions. For the other three markers, the northern region population was statistically distinct from other Brazilian region populations. CONCLUSION: The IL1A, IL4, NFKB1 and PAR1 gene polymorphism allelic distributions are homogeneous among the regional Brazilian populations, except for the northern region, which significantly differs from the other four Brazilian regions. Among the parental populations, the Native American population exhibited a higher incidence of alleles with risk of cancer or worse prognosis for cancer, which can indicate greater susceptibility to this disease. These genetic data may be useful for future studies on the association between these polymorphisms and cancer in the investigated populations.

The Spectrum of ß-Thalassemia Mutations in a Population from the Brazilian Amazon.

The spectrum of ß-thalassemia (ß-thal) mutations was investigated for the first time in a cohort of 33 unrelated patients from the Brazilian Amazon attending the Center for Hemotherapy and Hematology of the Pará Foundation (HEMOPA), in Belém, the state capital of Pará, Northern Brazil. Identification of the ß-thal mutations was made by direct genomic sequencing of the ß-globin gene. Mutations were identified in all patients, corresponding to a spectrum of 10 different point mutations and a total of 37 alleles studied. HBB: c.92 + 5G > A [IVS-I-5 (G > A)], was the most common ß-thal mutation, followed by HBB: c.118C > T [codon 39 (C > T)], HBB: c.-138C > T [-88 (C>T)], HBB: c.92 + 1G > A [IVS-I-1 (G > A)] and HBB: c.92 + 6T > C [IVS-I-6 (T > C)] mutations. These five mutations (four Mediterranean origin and one African origin) accounted for 86.5% of the ß-thal alleles. The profile of ß-thal mutations found in northern Brazil is different from those described in other regions of the country. In the southeast and south, the nonsense mutation HBB: c.118C > T is the most prevalent, followed by HBB: c.93-21G > A [IVS-I-110 (G > A)], whereas in the northeast, HBB: c.92 + 6T > C has been identified as the most common mutation, followed by HBB: c.92 + 1G > A. This heterogeneous geographical distribution is certainly related to the ancestry of Brazilian populations because they have similar genetic backgrounds (European, African and Amerindian), although with slightly different admixture proportions. Furthermore, the European contribution in the southeast and south was largely made up of immigrants of other nationalities, such as Italian and Spanish, in addition to Portuguese.

Serologically defined variations in malaria endemicity in Pará state, Brazil.

BACKGROUND: Measurement of malaria endemicity is typically based on vector or parasite measures. A complementary approach is the detection of parasite specific IgG antibodies. We determined the antibody levels and seroconversion rates to both P. vivax and P. falciparum merozoite antigens in individuals living in areas of varying P. vivax endemicity in Pará state, Brazilian Amazon region. METHODOLOGY/PRINCIPAL FINDINGS: The prevalence of antibodies to recombinant antigens from P. vivax and P. falciparum was determined in 1,330 individuals. Cross sectional surveys were conducted in the north of Brazil in Anajás, Belém, Goianésia do Pará, Jacareacanga, Itaituba, Trairão, all in the Pará state, and Sucuriju, a free-malaria site in the neighboring state Amapá. Seroprevalence to any P. vivax antigens (MSP1 or AMA-1) was 52.5%, whereas 24.7% of the individuals were seropositive to any P. falciparum antigens (MSP1 or AMA-1). For P. vivax antigens, the seroconversion rates (SCR) ranged from 0.005 (Sucuriju) to 0.201 (Goianésia do Pará), and are strongly correlated to the corresponding Annual Parasite Index (API). We detected two sites with distinct characteristics: Goianésia do Pará where seroprevalence curve does not change with age, and Sucuriju where seroprevalence curve is better described by a model with two SCRs compatible with a decrease in force of infection occurred 14 years ago (from 0.069 to 0.005). For P. falciparum antigens, current SCR estimates varied from 0.002 (Belém) to 0.018 (Goianésia do Pará). We also detected a putative decrease in disease transmission occurred ∼29 years ago in Anajás, Goianésia do Pará, Itaituba, Jacareacanga, and Trairão. CONCLUSIONS: We observed heterogeneity of serological indices across study sites with different endemicity levels and temporal changes in the force of infection in some of the sites. Our study provides further evidence that serology can be used to measure and monitor transmission of both major species of malaria parasite.

Plasmodium vivax infection in Anajás, State of Pará: no differential resistance profile among Duffy-negative and Duffy-positive individuals.

BACKGROUND: There is large body of evidence that states that invasion of Plasmodium vivax requires the Duffy antigen, but the universality of this specificity is certainly now under question with recent reports showing that in some parts of the world P. vivax infects and causes disease in Duffy-negative people. These findings reinforce the idea that this parasite is rapidly evolving, being able to use other receptors than Duffy to invade the erythrocytes, which may have an enormous impact in P. vivax current distribution. The presence of P. vivax infection in Duffy-negative individuals was investigated in a cross-sectional study conducted in Anajás, Archipelago of Marajó, State of Pará, which is an area of malaria transmission in the Brazilian Amazonia. METHODS: Duffy genotyping and Plasmodium species diagnostic assays were performed successfully in 678 individuals. An allele-specific primer polymerase chain reaction (PCR) technique was used for Duffy blood group genotyping. Identification of Plasmodium species was achieved by conventional blood smear light microscopy and a TaqMan-based real-time PCR method to detect mitochondrial genome of Plasmodium falciparum and P. vivax. RESULTS: Plasmodium spp. infection was detected in 137 samples (20.2%). Prevalence of each Plasmodium species was 13.9% P. vivax, 5.8% P. falciparum, and 0.6% P. vivax plus P. falciparum. Overall, 4.3% (29/678) were genotyped as Duffy-negative (FY*BES/*BES). Among Duffy-negative individuals 6.9% were P. vivax PCR positive and among Duffy-positive 14.2% were P. vivax PCR positive. Although lower, the risk of Duffy-negatives to experience a P. vivax blood stage infection was not significantly different to that of Duffy-positives. Furthermore, the genotypic and allelic frequencies of the Duffy blood group among P. vivax-infected patients and in the control group did not differ significantly, also suggesting no reduction in infection rates among the carriers of FY*BES allele. CONCLUSIONS: The data obtained in Anajás showed no differential resistance vivax malaria among Duffy-negative and Duffy-positive individuals. This result needs additional confirmation through a deeper evaluation in a larger sample of patients with P. vivax malaria and molecular parasite characterization. Nonetheless, this genetic profile of the parasite may be contributing to the high incidence of malaria in the municipality.

Balanced polymorphism in bottlenecked populations: the case of the CCR5 5' cis-regulatory region in Amazonian Amerindians.

The 5' cis-regulatory region of the CCR5 gene exhibits a strong signature of balancing selection in several human populations. Here we analyze the polymorphism of this region in Amerindians from Amazonia, who have a complex demographic history, including recent bottlenecks that are known to reduce genetic variability. Amerindians show high nucleotide diversity (pi = 0.27%) and significantly positive Tajima's D, and carry haplotypes associated with weak and strong gene expression. To evaluate whether these signatures of balancing selection could be explained by demography, we perform neutrality tests based on empiric and simulated data. The observed Tajima's D was higher than that of other world populations; higher than that found for 18 noncoding regions of South Amerindians, and higher than 99.6% of simulated genealogies, which assume nonequilibrium conditions. Moreover, comparing Amerindians and Asians, the Fst for CCR5 cis-regulatory region was unusually low, in relation to neutral markers. These findings indicate that, despite their complex demographic history, South Amerindians carry a detectable signature of selection on the CCR5 cis-regulatory region.

X-linked insertion/deletion polymorphisms: forensic applications of a 33-markers panel.

Insertion/deletion (INDEL) polymorphisms are diallelic markers with potential characteristics for use in forensics and biological anthropology, including: the simplicity of laboratory analysis, the possibility of genotyping many markers in a single PCR multiplex reaction, as well as analyzing markers with special inheritance types, such as those linked to the X chromosome (X-INDEL). In this work we developed a laboratory analysis methodology using a 33-INDEL marker panel for the X chromosome in a single PCR multiplex reaction, followed by a capillary electrophoresis run. We employed the panel to genotype a sample of 351 individuals of a mixed population from the Brazilian Amazon. The results demonstrate that the measurement of biostatistical parameters for forensic use in this population is compatible with prior estimates from other populations using current X-STR panels.

Assessing individual interethnic admixture and population substructure using a 48-insertion-deletion (INSEL) ancestry-informative marker (AIM) panel.

Estimating the proportions of different ancestries in admixed populations is very important in population genetics studies, and it is particularly important for detecting population substructure effects in case-control association studies. In this work, a set of 48 ancestry-informative insertion-deletion polymorphisms (INDELs) were selected with the goal of efficiently measuring the proportions of three different ancestries (sub-Saharan African, European, and Native American) in mixed populations. All selected markers can be easily analyzed via multiplex PCR and detected with standard capillary electrophoresis. A total of 593 unrelated individuals representative of European, African, and Native American parental populations were typed, as were 380 individuals from three Brazilian populations with known admixture patterns. As expected, the interethnic admixture estimates show that individuals from southern Brazil present an almost exclusively European ancestry; Afro-descendant communities in the Amazon region, apart from the major African contribution, present some degree of admixture with Europeans and Native Americans; and a sample from Belém, in the northeastern Amazon, shows a significant contribution of the three ethnic groups, although with a greater European proportion. In summary, a panel of ancestry-informative INDELs was optimized and proven to be a valuable tool for estimating individual and global ancestry proportions in admixed populations. The ability to accurately infer interethnic admixtures highlights the usefulness of this marker set for assessing population substructure in association studies, particularly those conducted in Brazilian and other Latin American populations sharing trihybrid ancestry patterns.

[Clinical and laboratorial alterations in Plasmodium vivax malaria patients and glucose-6-phosphate dehydrogenase deficiency treated with primaquine at 0.50 mg/kg/day]. / Alterações clínicolaboratoriais em pacientes com malária por Plasmodium vivax e deficiência de glicose-6-fosfato desidrogenase tratados com 0.50 mg/kg/dia de primaquina.

The adverse effects of primaquine (0.50 mg/kg/day) were investigated in eleven patients with vivax malaria (three patients with glucose-6-phosphate dehydrogenase deficiency). Clinical and laboratorial alterations indicated acute hemolysis in only the enzymopenic patients and treatment was interrupted. Our results suggest that screening for G6PD deficiency should be carried out in patients with vivax malaria infection in order to avoid complications due to primaquine.

Alterações clínicolaboratoriais em pacientes com malária por Plasmodium vivax e deficiência de glicose-6-fosfato desidrogenase tratados com 0, 50mg/kg/dia de primaquina / Clinical and laboratorial alterations in Plasmodium vivax malaria patients and glucose-6-phosphate dehydrogenase deficiency treated with primaquine at 0.50mg/kg/day

O efeito adverso da primaquina na dose de 0,50mg/kg/dia foi investigado em onze pacientes com malária vivax (três com deficiência de glicose-6-fosfato desidrogenase). Alterações clínicas e laboratoriais indicaram hemólise aguda apenas nos enzimopênicos, o que fez com que o tratamento fosse interrompido. Nossos resultados sugerem a necessidade do emprego de um teste de triagem para a deficiência de G6PD em áreas endêmicas de malária vivax a fim de se evitar complicações causadas pelo uso da primaquina.

The amazonian microcosm

Five hundred years after the arrival of the first Portuguese colonizers, the Brazilian Amazonia is predominantly inhabited by mestizos, formed by the admixture among three main ethnic groups (Amerindians, Europeans and Africans). On the other hand, the region is the habitat of the last culturally autonomous indigenous tribes in Brazil, most of them showing little (<5 percent) or no mixture with other ethnic groups, and also includes several communities founded by escaped African slaves, named quilombos, some of which still remains relatively isolated. Genetical (classic genetic polymorphisms, nuclear DNA and the mtDNA polymorphisms) and genetical-demographic (estimates of interethnic admixture) data have been obtained for these human groups. Estimates of interethnic admixture for urban populations show average values of 41 percent of Indigenous contribution, 12 percent of African contribution and 47 percent of European contribution, the data showing an increase of Indigenous contribution in the direction of Belém to Manaus, followed by the reduction of the African contribution in the same direction. On the other hand, Y-DNA and mtDNA data obtained for the population of Belém demonstrate that the contribution of indigenous females to the formation of the population was 10 times higher than that of indigenous men. Studies performed in Afro-Brazilian communities indicate that although African slaves imported in the northern region have been predominantly from Bantu-speaking Africa, the number of slaves from West Africa, particularly from the Atlantic West, brought to northern Brazil may have been higher than that indicated by historical records. With respect to Amerinds, analysis of classical genetic markers and DNA polymorphisms (tandemly repeated loci) in several Amerindian populations do not coincide, the former indicating that tribes of the northern margin of the Amazon river are less differentiated than those from the southern margin, and that the within-stock genetic differentiation for the Tupi group is higher than that between-stock.

Heterogeneity of Y chromosome markers among Brazilian Amerindians.

The allele frequency distribution of DYS19 and DYS199 loci were analyzed in 59 Brazilian Amerindians from five tribes from the Amazon region (Zoé, Awá-Guajá, Urubú-Kaapór, Katuena, and Kayapó, Xikrin of Bacajá village). Three different alleles of the DYS19 microsatellite (182-bp, 186-bp, and 190-bp) were found at average frequencies of 0.08, 0.85, and 0.07, respectively. The DYS199-T allele was identified in 78% of the Amerindians studied (43/55), the frequencies varying from 0.46-0.93. Four different haplotypes were found, the combination DYS19-186/DYS199-T being the most common (average frequency of 0.65), followed by DYS19-186/DYS199-C with an average frequency of 0.22. These four haplotypes have been found in five other Brazilian tribes, and most of them were also identified in Native populations from South, Central and North America. The observed variability at the DYS19 microsatellite is probably due to forward or back mutations from the putative ancestral 186-bp allele, since the mutation rate of this locus is high and the post-Columbian admixture of the Brazilian tribes studied is very low or undetectable to explain these data. On the other hand, the DYS19/DYS199 haplotype distribution may suggest that the two most common haplotypes (186-bp/T and 186-bp/C) were present among the population(s) that peopled the New World. Am. J. Hum. Biol. 11:481-487, 1999. Copyright 1999 Wiley-Liss, Inc.