José Luis B. Caeiro

Phylogenetics of worldwide human populations as determined by polymorphic Alu insertions

Alu elements, the largest family of interspersed repeats, mobilize throughout the genomes of primates by retroposition. Alu are present in humans in an excess of 500 000 copies per haploid genome. Since some of the insertion alleles have not reached fixation, they remain polymorphic and can be used as biallelic DNA marker systems in investigations of human evolution. In this study, six polymorphic Alu insertional (PAI) loci were used as genetic markers. These markers are thought to be selectively neutral. The presence of these six PAIs was determined by a polymerase chain reaction (PCR)‐based assay in 1646 individuals from 47 populations from around the world. Examination of the populations by plotting the first and second principal components, shows the expected segregation of populations according to geographical vicinity and established ethnic affinities. Centroid analysis demonstrated that sub‐Sahara populations have experienced higher than average gene flow and/or represent larger populations as compared to groups in other parts of the globe and especially to known inbreed populations. This is consistent with greater heterogeneity and diversity expected of source groups. In addition, maximum likelihood (ML) analyses were performed with these 47 populations and a hypothetical ancestral group lacking the insertion in all six loci. Analysis of our data supports the Out of Africa hypothesis. African populations and admixed groups of African descent formed a single monophyletic group with a basal placement on the tree, which grouped closest to the hypothetical ancestor.

Austronesian genetic signature in East African Madagascar and Polynesia

AbstractThe dispersal of the Austronesian language family from Southeast Asia represents the last major diaspora leading to the peopling of Oceania to the East and the Indian Ocean to the West. Several theories have been proposed to explain the current locations, and the linguistic and cultural diversity of Austronesian populations. However, the existing data do not support unequivocally any given migrational scenario. In the current study, the genetic profile of 15 autosomal STR loci is reported for the first time for two populations from opposite poles of the Austronesian range, Madagascar at the West and Tonga to the East. These collections are also compared to geographically targeted reference populations of Austronesian descent in order to investigate their current relationships and potential source population(s) within Southeast Asia. Our results indicate that while Madagascar derives 66.3% of its genetic makeup from Africa, a clear connection between the East African island and Southeast Asia can be discerned. The data suggest that although geographic location has influenced the phylogenetic relationships between Austronesian populations, a genetic connection that binds them beyond geographical divides is apparent.

Genetic characterization of four Austronesian-speaking populations

AbstractAscertaining the genetic relationships between Austronesian populations is paramount to understanding their dispersal throughout the islands of the Pacific and Indian Oceans. The start of the Austronesian expansion has been dated to approximately 6,000 years ago, and from linguistic and archeological evidence, the origin of this dispersal may have been the island of Formosa. Consequently, the Taiwanese aboriginal populations and their phylogenetic relationship to the Austronesian-speaking groups from Madagascar at the occidental fringes of the expansion are of great interest. In this study, allelic frequencies from six polymorphic point mutation loci were assessed in the Austronesian-speaking populations of Madagascar, the Atayal aborigines of Formosa, and the general populations of Bali and Java. These allelic frequencies were compared and analyzed with the corresponding values from eight other worldwide populations from geographically targeted regions. The group from Madagascar is genetically distinct from their east-African neighbor from Zimbabwe. Our data also indicates that the Ami and the Atayal aborigines in the island of Taiwan, which occupy adjacent territories, differ sharply genetically. Genetic differences were also found between the populations of Bali and Java, belying their geographical proximity. Our results indicate that the east-African population from Madagascar phylogenetically segregates intermediate between mainland east-African and east-Asian groups, corroborating linguistic data indicating the Austronesian influence on this population.

Red cell enzymes and plasma protein polymorphisms in the population of Cabo Verde (West Africa)

The genetic polymorphism of six red cell enzymes (ADA, AK1, ALAD, ESD, GLO1, and PGD) and 10 plasma proteins (AHSG, BF, F13A, F13B, GC, HP, ORM, PLG, TBG, and TF) is analyzed in a sample of 268 unrelated individuals from Cabo Verde (West Africa). The population of Cabo Verde was founded in the 15th century (1462), on the basis of a great number of slaves brought from the West African coast and a few Europeans, mainly from Portugal. The frequencies found in Cabo Verde for the majority of the markers are intermediate between those reported for Africans and Europeans. Further, the presence of alleles which are rarely or never seen in Blacks, but are common in Caucasians, suggest a substantial contribution of Europeans to the gene pool of the population of Cabo Verde.

Genetic Analysis of Erythrocyte Uridine Monophosphate Kinase and Aminolevulinate Dehydrase and Its Application to Biological Paternity Testing

Simultaneous determination of uridine monophosphate kinase (UMPK) and aminolevulinate dehydrase (ALAD) has been carried out after discontinuous starch gel electrophoresis in the Galician population (NW Spain), including 129 families with a total of 291 descendents. Formal genetic studies are in agreement with the autosomal codominant way of inheritance for each locus. No evidence of phenotype association between both loci among the offspring is observed. Chance of exclusion for non-fathers is 0.041 13 for UMPK and 0.0702 for ALAD configuring a total exclusion rate of 0.1085 when both systems are evaluated together.

Simultaneous Diagnosis of Coagulation Factor XIIIA (F13A) and Plasminogen (PLG) Phenotypes by Polyacrylamide Gel Isoelectric Focusing

In this paper, we report a simple rapid method for simultaneous determination of Coagulation Factor XIIIA (F13A) and plasminogen (PLG) phenotypes by PAGIF with a nominal pH range of 3.5 to 10, followed by immunofixation and silver stain. Critical considerations concerning the conditions of molecular separation and detection strategies are also presented.