ABSTRACT
A collaborative work was carried out by the Spanish and Portuguese ISFG Working Group (GEP-ISFG) to estimate Y-STR mutation rates. Seventeen Y chromosome STR loci (DYS19, DYS385, DYS389I and II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS460, DYS461, DYS635 [GATA C4], GATA H4, and GATA A10) were analyzed in a sample of 3,026 father/son pairs. Among 27,029 allele transfers, 54 mutations were observed, with an overall mutation rate across the 17 loci of 1.998 x 10(-3) (95% CI, 1.501 x 10(-3) to 2.606 x 10(-3)). With just one exception, all of the mutations were single-step, and they were observed only once per gametogenesis. Repeat gains were more frequent than losses, longer alleles were found to be more mutable, and the mutation rate seemed to increase with the father's age. Hum Mutat 26(6), 520-528, 2005. (c) 2005 Wiley-Liss, Inc.
Subject(s)
Chromosomes, Human, Y/genetics , Microsatellite Repeats/genetics , Mutation , Age Factors , Alleles , Base Sequence , DNA Mutational Analysis , Gene Frequency , Genetic Markers , Humans , Male , Molecular Sequence DataABSTRACT
Genetic relationships between populations can be studied by comparing genotypic and allelic similarities. This investigation aims to demonstrate that selected autosomal microsatellite markers could be used to study the genetic structures of different populations living in northwest Venezuela, in Zulia State. Seven autosomal systems (CSF1PO, TPOX, TH01, vWA, D7S820, D13S317, and D5S818) were tested by PCR in a multiplex format on 688 different chromosomes from unrelated individuals living in Maracaibo, "Isla de Toas," and "San José de Heras," and from two Amerindian populations from the "Sierra de Perijá," Barí' and Yukpa. Allele frequencies, Hardy-Weinberg equilibria, genetic distances, phylogenetic trees, and ethnic admixtures were estimated. The study shows the existence of a clear genetic difference among these populations in accordance with their historic evolution. The populations of Maracaibo and "Isla de Toas" showed a triracial origin, with a large European contribution, followed by an Amerindian component and a small African component. The indigenous groups, Barí' and Yukpa, showed exclusively an Amerindian component, and "San José de Heras" showed only an African component. These results indicate that microsatellite markers are useful for molecular anthropology in a regional and worldwide context and provide important genetic information about contemporary populations of Venezuela.
Subject(s)
Alleles , DNA/genetics , Gene Frequency , Genetics, Population/methods , Tandem Repeat Sequences , Electrophoresis, Polyacrylamide Gel , Female , Genetic Markers , Genotype , Humans , Male , Polymerase Chain Reaction , VenezuelaABSTRACT
Presentamos los primeros datos de secuencias STRs del cromosoma Y en tres poblaciones diferentes de Zulia, Venezuela. Haplotipos basados en el análisis de cuatro Y-STRs: DYS19, DYS390, DYS391 y DYS393 se construyeron en una muestra de 160 hombres no relacionados genéticamente. Se observó diferencias en las frecuencias de haplotipos específicos, en particular entre Maracaibo e Isla de Toas sobre Wayúu. En éstos, los haplotipos más frecuentes incluían alelos marcadores de poblaciones amerindias mientras que en poblaciones de Maracaibo e Isla de Toas incluían alelos de poblaciones europeas (AU)
Subject(s)
Male , Humans , Haplotypes/genetics , Y Chromosome/classification , Y Chromosome/genetics , Microsatellite Repeats/genetics , Venezuela , Genetic Markers , Genetics, PopulationABSTRACT
Como parte de un estudio para describir la variabilidad genética en la región del Zulia, un estado al noroeste de Venezuela, en este trabajo se ha estudiado el locus hipervariable D1S80 en individuos nativos de cuatro diferentes poblaciones de ese estado, tres de ellas, predominantemente caucasoides y una amerindia. El Indice de Fijación, Fst, reveló diferencias significativas entre las poblaciones estudiadas y las distancias genéticas fueron también significativas entre todas las poblaciones excepto entre dos de las poblaciones de origen caucásico. Los resultados indican la utilidad del locus D1S80 para evaluar la contribución étnica diferencial de poblaciones mezcladas (AU)
Subject(s)
Female , Male , Humans , Minisatellite Repeats , Chromosomes, Human, Pair 1/genetics , Genetics, Population , Forensic Medicine/methods , VenezuelaABSTRACT
Allele frequencies for nine autosomal STRs loci were obtained from individuals from a sample of unrelated individuals born in Venezuela.
Subject(s)
Alleles , Genetics, Population , Tandem Repeat Sequences , Genetic Linkage , Humans , Polymerase Chain Reaction/methods , VenezuelaABSTRACT
The D1S80 locus in 122 individuals from Maracaibo, Venezuela, was studied to verify the genetic relationship of this sample with 32 other reported world populations derived from different ethnic groups. All analyses reveal that the Venezuelan sample has a main European genetic contribution, followed by contribution from Amerindians, and a small contribution of Africans. The population of Maracaibo has a high level of heterozygosity, as expected for populations with an important level of recent admixture. Am. J. Hum. Biol. 12:616-622, 2000. Copyright 2000 Wiley-Liss, Inc.
ABSTRACT
PURPOSE: To identify carrier females in segregant families of haemophilia A from Zulia state-Venezuela. PATIENTS AND METHODS: The polymorphisms' analysis linked to the gene, independently of the mutation nature is the most suitable method to identify carriers, because it permits to track the mutated gene. This study is comprised of 139 ADN samples distributed in 20 families affected by haemophilia A. The diagnosis of carrier was made by polymerase chain reaction (PCR), a fragment of 142 pb corresponding to intron 18 of the factor VIII gene, which shows a restriction polymorphism for the Bcl I enzyme. RESULTS: The frequency of the Bcl I alleles in the 43 unrelated individuals was 0.35 and 0.65 for the 142 pb and 99 + 43 pb, respectively. In the 35 women that required diagnosis, we were able to establish the carrier status for 11, and 4 were excluded to be. CONCLUSIONS: The Bcl I polymorphism at the FVIII gene was useful in the 43% (15/35) of the women that required diagnosis. It's possible to identify carriers for haemophilia A in most of the families from Zulia state-Venezuela employing several polymorphisms at the Factor VIII gene.
Subject(s)
Factor VIII/genetics , Genes, bcl-1/genetics , Genetic Carrier Screening/methods , Hemophilia A/genetics , Female , Humans , Male , Pedigree , Polymorphism, Genetic , VenezuelaABSTRACT
Cystic Fibrosis (CF) is a severe and relatively common autosomic recessive disease caused by a variety of mutations in the CFTR gene. The most frequent mutation worldwide, consists of the deletion of the phenylalanine codon at position 508 (delta F508). Here we report the first cases of prenatal diagnosis of CF by DNA analysis in couples at risk in Venezuela. The study focused on the detection of delta F508 alleles analyzing DNA recovered directly from amniocytes or from their cultures, using the polymerase chain reaction (PCR) and polyacrylamide gel electrophoresis. Two of three fetuses resulted homozygotic for the delta F508 allele and the third one turned out to be a delta F508 carrier. This information sustained the genetic counseling of the couples and allowed them to take objective reproductive decisions, a direct consequence of the availability of gene analysis at the DNA level.
