Carvajal-Carmona, L. G., Ophoff, R., Service, S., Hartiala, J., Molina, J., Leon, P. et al. Genetic demography of Antioquia (Colombia) and the Central Valley of Costa Rica. Hum. Genet. 112, 534-541

The Galton Laboratory, Department of Biology (Wolfson House), University College London, UK.
Human Genetics (Impact Factor: 4.82). 05/2003; 112(5-6):534-41. DOI: 10.1007/s00439-002-0899-8
Source: PubMed


We report a comparative genetic characterization of two population isolates with parallel demographic histories: the Central Valley of Costa Rica (CVCR) and Antioquia (in northwest Colombia). The analysis of mtDNA, Y-chromosome and autosomal polymorphisms shows that Antioquia and the CVCR are genetically very similar, indicating that closely related parental populations founded these two isolates. In both populations, the male ancestry is predominantly European, whereas the female ancestry is mostly Amerind. In agreement with their isolation, the Amerindian mtDNA diversity of Antioquia and the CVCR is typical of ethnically-defined native populations and is markedly lower than in other Latin American populations. A comparison of linkage disequilibrium (LD) at 18 marker pairs in Antioquia and the CVCR shows that markers in LD in both populations are located at short genetic distances (<approximately 1 cM), whereas markers separated by greater distances are in LD only in the CVCR. This difference probably reflects stochastic variation of LD at the limited number of genome regions compared. The genetic similarity of the populations from Antioquia and the CVCR together with differences in LD between them should be exploitable for the identification and fine mapping of shared disease-related gene variants.

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    • "The heterogeneity caused by different admixture proportions is not exclusive to Mexican–Mestizo populations ; it has also been described in Latin America with some peculiarities. Although Amerindian maternal ancestry is prevalent in Central America and the North region of South America (>80%), diverse South American populations show lower frequencies of this Native American ancestry (<50%), increasing the European and African ancestries in the same way (Carvalho-Silva et al., 2001; Sans et al., 2002; Carvajal-Carmona et al., 2003; Corach et al., 2010; Lao et al., 2010; Rojas et al., 2010). There are some interesting exceptions to the pattern in Latin America, such as the city of Melo (Uruguay ) and Cuba, where the African maternal ancestry prevails with 45.3 and 52%, respectively (Sans et al., 2002; Mendizabal et al., 2008). "
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    ABSTRACT: The maternal ancestry (mtDNA) has important applications in different research fields, such as evolution, epidemiology, identification, and human population history. This is particularly interesting in Mestizos, which constitute the main population in Mexico (∼93%) resulting from post-Columbian admixture between Spaniards, Amerindians, and African slaves, principally. Consequently, we conducted minisequencing analysis (SNaPshot) of 11 mitochondrial single-nucleotide polymorphisms in 742 Mestizos of 10 populations from different regions in Mexico. The predominant maternal ancestry was Native American (92.9%), including Haplogroups A, B, C, and D (47, 23.7, 15.9, and 6.2%, respectively). Conversely, European and African ancestries were less frequent (5.3 and 1.9%, respectively). The main characteristics of the maternal lineages observed in Mexican-Mestizos comprised the following: 1) contrasting geographic gradient of Haplogroups A and C; 2) increase of European lineages toward the Northwest; 3) low or absent, but homogeneous, African ancestry throughout the Mexican territory; 4) maternal lineages in Mestizos roughly represent the genetic makeup of the surrounding Amerindian groups, particularly toward the Southeast, but not in the North and West; 5) continuity over time of the geographic distribution of Amerindian lineages in Mayas; and 6) low but significant maternal population structure (FST = 2.8%; P = 0.0000). The average ancestry obtained from uniparental systems (mtDNA and Y-chromosome) in Mexican-Mestizos was correlated with previous ancestry estimates based on autosomal systems (genome-wide single-nucleotide polymorphisms and short tandem repeats). Finally, the comparison of paternal and maternal lineages provided additional information concerning the gender bias admixture, mating patterns, and population structure in Mestizos throughout the Mexican territory. Am J Phys Anthropol, 2013. © 2013 Wiley Periodicals, Inc.
    American Journal of Physical Anthropology 08/2013; 151(4). DOI:10.1002/ajpa.22293 · 2.38 Impact Factor
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    • "The Colombian family in this study originates from Antioquia, which is a young admixture that was founded in the 16–17th century by only a few hundred American natives and immigrants mainly from Spain (Carvajal-Carmona et al., 2003). The people in the region have remained relatively isolated since its origin (Carvajal-Carmona et al., 2003). Young genetic isolates confer an advantage to gene-mapping, and are usually enriched for specific Mendelian traits that often occur in the population because of a founder effect (Sheffield et al., 1998). "
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    ABSTRACT: Recent evidence suggests that rare genetic variants within the TREM2 gene are associated with increased risk of Alzheimer's disease. TREM2 mutations are the genetic basis for a condition characterized by polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL) and an early-onset dementia syndrome. TREM2 is important in the phagocytosis of apoptotic neuronal cells by microglia in the brain. Loss of function might lead to an impaired clearance and to accumulation of necrotic debris and subsequent neurodegeneration. In this study, we investigated a consanguineous family segregating autosomal recessive behavioral variant FTLD from Antioquia, Colombia. Exome sequencing identified a nonsense mutation in TREM2 (p.Trp198X) segregating with disease. Next, using a cohort of clinically characterized and neuropathologically verified sporadic AD cases and controls, we report replication of the AD risk association at rs75932628 within TREM2 and demonstrate that TREM2 is significantly overexpressed in the brain tissue from AD cases. These data suggest that a mutational burden in TREM2 may serve as a risk factor for neurodegenerative disease in general, and that potentially this class of TREM2 variant carriers with dementia should be considered as having a molecularly distinct form of neurodegenerative disease.
    Neurobiology of aging 04/2013; 34(8). DOI:10.1016/j.neurobiolaging.2013.02.016 · 5.01 Impact Factor
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    • "The stronger Caucasian component in some LAP can be attributed to recent European migration [14], such as that of urban populations from Argentina and some Brazilian populations, or to relatively stronger Caucasian proportions generated at colonial times in areas where Amerindian populations were low at the time of the arrival of Europeans, which is thought to be the case of the Costa Rican Central Valley and the Colombians from Medellin [70, 71]. "
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    ABSTRACT: The outcome of hematopoietic stem cell transplantation (HSCT) is shaped by both clinical and genetic factors that determine its success. Genetic factors including human leukocyte antigen (HLA) and non-HLA genetic variants are believed to influence the risk of potentially fatal complications after the transplant. Moreover, ethnicity has been proposed as a factor modifying the risk of graft-versus-host disease. The populations of Latin America are a complex array of different admixture processes with varying degrees of ancestral population proportions that came in different migration waves. This complexity makes the study of genetic risks in this region complicated unless the extent of this variation is thoroughly characterized. In this study we compared the HLA-A and HLA-B allele group profiles for 31 Latin American populations and 61 ancestral populations from Iberia, Italy, Sub-Saharan Africa, and America. Results from population genetics comparisons show a wide variation in the HLA profiles from the Latin American populations that correlate with different admixture proportions. Populations in Latin America seem to be organized in at least three groups with (1) strong Amerindian admixture, (2) strong Caucasian component, and (3) a Caucasian-African gradient. These results imply that genetic risk assessment for HSCT in Latin America has to be adapted for different population subgroups rather than as a pan-Hispanic/Latino analysis.
    11/2012; 2012:136087. DOI:10.1155/2012/136087
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