Polymorphic variations influencing fetal hemoglobin levels: association study in beta-thalassemia carriers and in normal individuals of Portuguese origin.

Three major loci have been associated with HbF levels, including -158C/T (XmnI) at HBG2 promoter region, and several polymorphisms at BCL11A intron-2 and HBS1L-MYB (HMIP) intergenic region. Mutations in the KLF1 gene were recently associated with increased HbF levels. This study aims to evaluate whether genetic variability at these loci influences HbF levels in β-thalassemia carriers and in normal individuals of Portuguese origin.

Distribution of the - 13910C>T polymorphism in the general population of Portugal and in subjects with gastrointestinal complaints associated with milk consumption.

Background: The - 13910C>T polymorphism has been associated with lactase persistence (LP) in European populations.

Aim: To assess - 13910C>T genotypes across Portugal and in adult individuals with unspecific gastrointestinal complaints associated with milk consumption.

Subjects And Methods: This study genotyped - 13910C>T in the general population from Northern (n = 64), Central (n = 70) and Southern (n = 65) Portugal and in 40 subjects with gastrointestinal symptoms.

Y-chromosome diversity in central Portugal reveals signatures of ancient maritime expansions.

The genetic diversity of human populations in Portugal results from several different demographic events that occurred in distinct prehistorical and historical periods. The main objective of this study was to examine if patterns of Y-chromosome diversity explained by ancient maritime Mediterranean expansions can be observed in Coimbra district (central-west region of Portugal). A total of 125 male DNA samples were typed for 16 Y-SNPs and eight Y-STRs using standard molecular methodologies.

G6PD deficient alleles and haplotype analysis of human G6PD locus in São Tomé e Príncipe (West Africa).

A population sample from São Tomé e Príncipe (West Africa) was screened for the G6PD-deficient variants A- (376G/202A), Betica (376G/968C), and Santa Maria (376G/542T). G6PD locus haplotype diversity was also investigated using six intragenic RFLPs (FokI, PvuII, BspHI, PstI, BclI, NlaIII) and a (CTT)n microsatellite 18.61 kb within the G6PD locus.

Mutations and haplotype diversity in 70 Portuguese G6PD-deficient individuals: an overview on the origin and evolution of mutated alleles.

G6PD deficiency mutational profile and haplotype diversity using 6 RFLPs (FokI/PvuII/BspHI/PstI/BclI/NlaIII) and a (CTT)(n) microsatellite, were investigated in 70 G6PD-deficient Portuguese individuals. All but one G6PD A-(376G/202A) variants (44/45) have a single haplotype (+/+/-/+/-/+/195). G6PD Betica(376G/968C) alleles (n=10) have a single RFLP haplotype (+/-/-/+/-/+) and 4 different (CTT)(n) repeats.

Testing hierarchical levels of population sub-structuring: the Azores islands (Portugal) as a case study.

The Azores archipelago (Portugal) is formed by nine islands whose relative positions define them as three geographical groups: Eastern (S. Miguel and Sta. Maria), Central (Terceira, Faial, Pico, Graciosa and S.

Genetic structure of Flores island (Azores, Portugal) in the 19th century and in the present day: evidence from surname analysis.

The island of Flores is the most westerly of the Azores archipelago (Portugal). Despite its marked geographic isolation and reduced population size, biodemographic and genetic studies conducted so far do not support the idea that its population constitutes a genetic isolate. In this study we conducted a surname analysis of the Flores population for two time periods: the second half of the 19th century and the present day.

Understanding differences between phylogenetic and pedigree-derived mtDNA mutation rate: a model using families from the Azores Islands (Portugal).

We analyzed the control region of the mitochondrial DNA (mtDNA) from maternally related individuals originating from the Azores Islands (Portugal) in order to estimate the mutation rate of mtDNA and to gain insights into the process by which a new mutation arises and segregates into heteroplasmy. Length and/or point heteroplasmies were found at least in one individual of 72% of the studied families. Eleven new point substitutions were found, all of them in heteroplasmy, from which five appear to be somatic mutations and six can be considered germinal, evidencing the high frequency of somatic mutations in mtDNA in healthy young individuals.

Determination of human caucasian mitochondrial DNA haplogroups by means of a hierarchical approach.

In this paper we propose a hierarchical approach that allows the screening of mitochondrial DNA (mtDNA) haplogroups in populations that have essentially West Eurasian mtDNA backgrounds but that could have some non-West Eurasian contributions. To develop and validate this scheme, we used data on 18 coding region polymorphisms (17 analyzed by RFLP analysis and 1 by sequencing) and sequences of hypervariable segment I (HVSI) of the mtDNA control region from the Azores Islands (Portugal) population. The proposed scheme allows the characterization of almost all West Eurasian and African major clusters by means of RFLPs.