Latitudinal clinal variation in wing size and shape has evolved North American populations of Drosophila subobscura within about 20 years since colonization. While the cline is consistent to that found original European (and globally other species), different parts have on two continents. This clearly suggests 'chance necessity' are simultaneously playing their roles process adaptation. We report here rapid thermal evolution (but not size) apparently at odds with suggestion. Three replicated...

Abstract Background Many properties of organisms show great robustness against genetic and environmental perturbations. The terms canalization developmental stability were originally proposed to describe the ability an organism resist perturbations produce a predictable target phenotype regardless random noise. However, extent which are controlled by same set genes share underlying regulatory mechanisms is largely unresolved. Results We have analyzed effects clinal variation (inversion...

African honey bee subspecies Apis mellifera scutellata began to spread in the American continent from southern Brazil 1956. The process of Africanization involved both maternal and paternal bidirectional gene flow between European Africanized bees. In Argentina, bees dominate northern semitropical regions a hybrid area is defined (ca. 32°–34°latitude). Although previous analysis has been carried out Buenos Aires province, no made south this latitude. We used mitochondrial DNA (mtDNA) assays...

Abstract The southern coastline of South America is a remarkable area to evaluate how Quaternary glacial processes impacted the demography near-shore marine biota. Here we present new phylogeographic analyses in pulmonate Siphonaria lessonii across its distribution, from northern Chile Pacific Uruguay Atlantic. Contrary our expectations, populations southwestern Atlantic, an that was less by ice during maxima, showed low genetic diversity and evidence recent expansion, similar patterns...

The genetic and ecological basis of viability developmental time differences between Drosophila buzzatii D. koepferae were analysed using the isofemale line technique. Several lines sampled from pairs allopatric/sympatric populations each species. Flies reared in media prepared with decaying tissues two main natural cactus hosts This experimental design enabled us to evaluate relative contribution phenotypic plasticity, variation genotype by environment interaction (G x E) total for fitness...

Inversion polymorphisms often have been associated with fitness variation. Cactophilic Drosophila buzzatii has used widely for the study of maintenance chromosomal The purpose this paper is to address relative importance variable selection regimes use three different host cacti and antagonistic pleiotropy in Using homokaryotypic stocks derived from several lines homozygous four second-chromosome arrangements, we show that inversions significantly affect first-instar larva adult viability...

The genetic structure of populations/species was established during the Quaternary glaciations. Over last 250 ka (Pleistocene), South American marine biogeographic history recorded three main glaciations: most extensive one between 140 and 180 ka, a minor 60 70 glaciation approximately 15 35 ka. With aim assessing pattern molecular diversity historical demography weakfish (Cynoscion guatucupa), 365 bp sequence mitochondrial control region amplified at four coastal sites located in...

This study analyzed the morphometric, microsatellite loci and mitochondrial control region variation of striped weakfish from two feeding spawning grounds in coastal area Buenos Aires province.The characterization body shape proved to be different between sites.Genetic structure analysis showed that main source genetic was within populations rather than among low differentiation observed sites.The inhabiting areas would exhibit management units agreement with other fishes studied both areas.

This study highlights the analysis of morphological and genetic variation common sea bream Pagrus pagrus, compares its two main areas concentration: northern (35ºS - 38ºS) southern (39ºS 41ºS) Buenos Aires coast Argentine Sea. Body shape characterization presented significantly different morphotypes (Wilks' Lambda=0.224, P<0.001). Northern individuals displayed a higher middle area while ones were smaller their caudal peduncle was shorter. The did not yield significant differences either...

Uruguay is characterized by having an Africanization gradient in its honey bee (Apis mellifera) populations from areas bordering Brazil to the most remote locations. Morphological differences have also been found among Varroa destructor different regions. A possible explanation for these morphological changes mites could be explained correlations host/parasite A. mellifera/V. system. The objective of present study was identify mellifera ecotypes and their correlation with V. populations,...

P. IRIARTE AND R. J. OWEN. 1996. Forty-seven strains of Campylobacter jejuni were examined by PCR-RFLP analysis 23S rRNA genes. Seven different molecular profiles detected a combination HpaII AluI and DdeI digest analysis. Most (83%) strains, including those with Penner serotypes from hosts, had the same profiles. The high level conservation apparent within rDNA sequences confirmed their value as targets in species-specific PCR identification assays but not for subtypic discrimination Camp. jejuni.

This paper aimed to estimate the frequency of occurrence and types chromosomal abnormalities found in 141 infertile men with abnormal semen parameters.the type were determined male mitotic karyotype analysis from peripheral blood through chromosome banding techniques before assisted reproduction procedures.In this series men, 19 (13%) had anomalies 35 (25%) polymorphic variants. The main reciprocal translocations marker chromosomes mosaic.These results stress relevance cytogenetic studies...

Biological invasions are excellent opportunities to study the evolutionary forces leading adaptation of a species new habitat. Knowledge introduction history colonizing helps tracking routes and assists in defining management strategies for invasive species. The Palearctic Drosophila subobscura is good model organism colonizations since it was detected Chile western North America three decades ago later on Atlantic coast Argentina. To unravel origin Argentinean colonizers two populations...

Abstract. Inversion polymorphisms often have been associated with fitness variation. Cactophilic Drosophila buzzatii has used widely for the study of maintenance chromosomal The purpose this paper is to address relative importance variable selection regimes use three different host cacti and antagonistic pleiotropy in Using homokaryotypic stocks derived from several lines homozygous four second-chromosome arrangements, we show that inversions significantly affect first-instar larva adult...

Marine organism adaptive capacity to different environmental conditions is a research priority understand what are important in structuring the spatial distribution of natural populations. In this context, study evaluates whether potential differences Siphonaria lessonii morphology (size and shell shape) physiology (water loss regulation) at shore heights linked genetically distinguishable individuals. To achieve goal, we compared size-frequency distribution, morphometric, genetic data...

Abstract The infection of honey bees, Apis mellifera L. (Hymenoptera: Apidae), by the microsporidian Nosema ceranae is one factors related to increase in colony losses and decrease production observed recent years. However, these effects seem differ depending on climate zone. range prevalence N. have increased significantly last decades, with different consequences northern southern temperate areas. existence various isolates from distant geographical areas, which probably exhibit degrees...

Abstract Pomatomus saltatrix is a high-value marine pelagic coastal fish, that fished throughout subtropical and temperate waters around the world. Despite its large economic potential, there are no global data on genetic diversity, which could compromise conservation of species. The aim this study was to analyse genetic-evolutionary structuring species, with intention evaluating different P. stocks may indicate potential Based 157 Cytochrome C Oxidase Subunit 1 sequences, molecular...

Abstract Second chromosome inversions and genotypic frequencies at seven allozyme loci were determined in a natural population of the cactophilic species Drosophila buzzatii that uses as breeding sites necrotic cladodes prickly pear Opuntia quimilo rotting stems cardón, Trichocereus terschekii. Different processes govern evolutionary fate inversion polymorphisms. A pattern heterotic balance for seems to be acting uniformly each site could depend on different regimes density-dependent...