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Historical records and genetic analyses indicate that Latin Americans trace their ancestry mainly to the admixture of Native Americans, Europeans and Sub-Saharan Africans. Using novel haplotype-based methods here we infer the sub-populations involved in admixture for over 6,500 Latin Americans and evaluate the impact of sub-continental ancestry on the physical appearance of these individuals. We find that pre-Columbian Native genetic structure is mirrored in Latin Americans and that sources of non-Native ancestry, and admixture timings, match documented migratory flows. We also detect South/East Mediterranean ancestry across Latin America, probably stemming from the clandestine colonial migration of Christian converts of non-European origin (Conversos). Furthermore, we find that Central Andean ancestry impacts on variation of facial features in Latin Americans, particularly nose morphology, possibly relating to environmental adaptation during the evolution of Native Americans.

Valuable insights into the history of human populations have been obtained by studying the genetic composition of their domesticated species. Here we address some of the long-standing questions about the origin and subsequent movements of goat pastoralism in Northern Africa. We present the first study combining results from mitochondrial DNA (mtDNA) and Y chromosome loci for the genetic characterization of a domestic goat population. Our analyses indicate a remarkably high diversity of maternal and paternal lineages in a sample of indigenous goats from the northwestern fringe of the African continent. Median-joining networks and a multidimensional scaling of ours and almost 2000 published mtDNA sequences revealed a considerable genetic affinity between goat populations from the Maghreb (Northwest Africa) and the Near East. It has been previously shown that goats have a weak phylogeographic structure compatible with high levels of gene flow, as demonstrated by the worldwide dispersal of the predominant mtDNA haplogroup A. In contrast, our results revealed a strong correlation between genetic and geographical distances in 20 populations from different regions of the world. The distribution of Y chromosome haplotypes in Maghrebi goats indicates a common origin for goat patrilines in both Mediterranean coastal regions. Taken together, these results suggest that the colonization and subsequent dispersal of domestic goats in Northern Africa was influenced by the maritime diffusion throughout the Mediterranean Sea and its coastal regions of pastoralist societies whose economy included goat herding. Finally, we also detected traces of gene flow between goat populations from the Maghreb and the Iberian Peninsula corroborating evidence of past cultural and commercial contacts across the Strait of Gibraltar.

J Med Genet. 1999 Aug;36(8):629-32. Two pairs of proven monozygotic twins discordant for familial amyloid neuropathy (FAP) TTR Met 30. Munar-Qués M, Pedrosa JL, Coelho T, Gusmão L, Seruca R, Amorim A, Sequeiros J. Grupo de Estudio de la PAF, Palma de Mallorca, Spain. Abstract Twin studies are an important tool in medical genetics for the evaluation of the relative roles of genetic and non-genetic factors in several diseases. Familial amyloidotic polyneuropathy type I (FAP-I), TTR Met 30, was present in two sets of proven monozygotic (MZ) twins, one from Majorca and the other from Portugal. Monozygosity was established by analysis of DNA polymorphisms. Both pairs were discordant for age at onset and some clinical manifestations of FAP-I. We reviewed the differences in age at onset and clinical features in both sets and in two other pairs of presumed MZ twins with FAP-I and compared them with those in MZ twin pairs with other Mendelian disorders, such as neurofibromatosis type 1, Huntington's disease, facioscapulohumeral muscular dystrophy, and myotonic dystrophy. We conclude that, in addition to the postulated modifying genes, there must be a significant contribution from non-genetic factors to the phenotypic variability of FAP-I (age at onset and clinical expression), either because of environmental differences or stochastic events during (or after) the twinning process. PMID: 10465115 [PubMed - indexed for MEDLINE]PMCID: PMC1762972

Made available in DSpace on 2019-03-19T02:10:11Z (GMT). No. of bitstreams: 1 tese_13063_Tese - Raquel Silva dos Reis.pdf: 5806087 bytes, checksum: 422c281e304bbd0407257b8c011ffb09 (MD5) Previous issue date: 2019-02-28 Além de sua valiosa utilidade na prática forense, a análise do DNA mitocondrial (mtDNA) é uma ferramenta confiável para desvendar as origens de populações miscigenadas, como as brasileiras. O Espírito Santo (ES), assim como os demais estados costeiros do país, possui uma população moldada por três principais raízes ancestrais: ameríndios, africanos e europeus. Entre estes últimos, os descendentes da antiga Pomerânia destacam-se pela preservação dos aspectos tradicionais de sua cultura, especialmente a língua pomerana. Embora a diversidade genética mitocondrial no ES tenha investigada por um estudo anterior, a base de dados disponibilizada apresenta reduzido número amostras (N=97) cuja composição étnica, origem geográfica e abrangência territorial são desconhecidas. Com o objetivo de aprofundar o conhecimento sobre a ancestralidade materna e investigar a estratificação genética da população, dados da região controle do mtDNA foram produzidos para população geral (N=214) e comunidades pomeranas (N=77), totalizando 291 haplótipos. A amostragem da população geral incluiu indivíduos das 4 macrorregiões do ES, a saber, Metropolitana (N=81), Sul (N=62), Central (N=54) e Norte (N=17). Em relação à população geral, os altos valores de diversidade haplotípica (H = 99,9%) e de diferenças entre pares de haplótipos (mean number of pairwise diferences - MNPD = 16,9) encontrados estão de acordo com os relatados para outras populações na região Sudeste do Brasil. Quanto à herança materna, o ES destacou-se pela predominância de haplogrupos europeus (49,1%), embora a macrorregião Norte tenha apresentado um perfil mais africano (47,1%). Embora não estatisticamente significantes, as análises de distâncias genéticas indicaram uma estratificação genética da população geral, o que comprometeria a adoção de uma base de dados única de linhagens de mtDNA com finalidade forense para todo o ES. Entre os pomeranos, o menor valor de MNPD (11,2) e o alto percentual de haplótipos compartilhados (15%) foram indicativos de eventos fundadores. A análise de FST demonstrou que os pomeranos (com 98,7% de linhagens europeias) são geneticamente isolados das outras populações do Brasil. Este estudo evidenciou que o Estado do ES apresenta singularidades em relação à diversidade intra e interpopulacional do mtDNA. Mesmo após cinco séculos de miscigenação, a população atual do Espírito Santo abriga marcas genéticas que remontam aspectos históricos de sua formação.

Prieto Solla, Lourdes et al., The GHEP-ISFG Working Group performed a collaborative exercise to monitor the current practice of mitochondrial (mt)DNA reporting. The participating laboratories were invited to evaluate a hypothetical case example and assess the statistical significance of a match between the haplotypes of a case (hair) sample and a suspect. A total of 31 forensic laboratories participated of which all but one used the EMPOP database. Nevertheless, we observed a tenfold range of reported LR values (32-333.4), which was mainly due to the selection of different reference datasets in EMPOP but also due to different applied formulae. The results suggest the need for more standardization as well as additional research to harmonize the reporting of mtDNA evidence. © 2012 Elsevier Ireland Ltd., WP was partly supported by the Austrian Science Fund FWF (P22880).

To investigate the male genetic legacy of the Arab rule in southern Europe during medieval times, we focused on specific Northwest African haplogroups and identified evolutionary close STR-defined haplotypes in Iberia, Sicily and the Italian peninsula. Our results point to a higher recent Northwest African contribution in Iberia and Sicily in agreement with historical data, southern Italian regions known to have experienced long-term Arab presence also show an enrichment of Northwest African types. The forensic and genomic implications of these findings are discussed.