scholarly journals Latitudinal Variation in Population Structure and Reproductive Pattern of the Endemic South American Shrimp Artemesia Longinaris (Decapoda: Penaeoidea)

2007 ◽  
Vol 27 (4) ◽  
pp. 548-552 ◽  
Author(s):  
Antonio L. Castilho ◽  
Raymond T. Bauer ◽  
María A. Gavio ◽  
Enrique E. Boschi ◽  
Rogério C. Costa ◽  
...  
2015 ◽  
Vol 87 (2) ◽  
pp. 1239-1258 ◽  
Author(s):  
ASTOLFO G.M. ARAUJO

Eastern South America, or what is today Brazilian territory, poses interesting questions about the early human occupation of the Americas. Three totally distinct and contemporaneous lithic technologies, dated between 11,000 and 10,000 14C BP, are present in different portions of the country: the Umbu tradition in the south, with its formal bifacial industry, with well-retouched scrapers and bifacial points; the Itaparica tradition in the central-west / northwest, totally unifacial, whose only formal artifacts are limaces; and the "Lagoa Santa" industry, completely lacking any formal artifacts, composed mainly of small quartz flakes. Our data suggests that these differences are not related to subsistence or raw-material constraints, but rather to different cultural norms and transmission of strongly divergent chaînes opératoires. Such diversity in material culture, when viewed from a cultural transmission (CT) theory standpoint, seems at odds with a simple Clovis model as the origin of these three cultural traditions given the time elapsed since the first Clovis ages and the expected population structure of the early South American settlers.


2005 ◽  
Vol 6 (3) ◽  
pp. 431-443 ◽  
Author(s):  
Sabrina Rosa ◽  
Michel C. Milinkovitch ◽  
Koen Van Waerebeek ◽  
Jehanne Berck ◽  
Jorge Oporto ◽  
...  

2009 ◽  
Vol 364 (1530) ◽  
pp. 2749-2761 ◽  
Author(s):  
L. David Sibley ◽  
Asis Khan ◽  
James W. Ajioka ◽  
Benjamin M. Rosenthal

Toxoplasma gondii is one of the most widespread parasites of domestic, wild, and companion animals, and it also commonly infects humans. Toxoplasma gondii has a complex life cycle. Sexual development occurs only in the cat gut, while asexual replication occurs in many vertebrate hosts. These features combine to create an unusual population structure. The vast majority of strains in North America and Europe fall into three recently derived, clonal lineages known as types I, II and III. Recent studies have revealed that South American strains are more genetically diverse and comprise distinct genotypes. These differences have been shaped by infrequent sexual recombination, population sweeps and biogeography. The majority of human infections that have been studied in North America and Europe are caused by type II strains, which are also common in agricultural animals from these regions. In contrast, several diverse genotypes of T. gondii are associated with severe infections in humans in South America. Defining the population structure of T. gondii from new regions has important implications for transmission, immunogenicity and pathogenesis.


2016 ◽  
Vol 3 (7) ◽  
pp. 160291 ◽  
Author(s):  
J. I. Hoffman ◽  
G. J. Kowalski ◽  
A. Klimova ◽  
L. J. Eberhart-Phillips ◽  
I. J. Staniland ◽  
...  

Understanding the causes of population decline is crucial for conservation management. We therefore used genetic analysis both to provide baseline data on population structure and to evaluate hypotheses for the catastrophic decline of the South American sea lion ( Otaria flavescens ) at the Falkland Islands (Malvinas) in the South Atlantic. We genotyped 259 animals from 23 colonies across the Falklands at 281 bp of the mitochondrial hypervariable region and 22 microsatellites. A weak signature of population structure was detected, genetic diversity was moderately high in comparison with other pinniped species, and no evidence was found for the decline being associated with a strong demographic bottleneck. By combining our mitochondrial data with published sequences from Argentina, Brazil, Chile and Peru, we also uncovered strong maternally directed population structure across the geographical range of the species. In particular, very few shared haplotypes were found between the Falklands and South America, and this was reflected in correspondingly low migration rate estimates. These findings do not support the prominent hypothesis that the decline was caused by migration to Argentina, where large-scale commercial harvesting operations claimed over half a million animals. Thus, our study not only provides baseline data for conservation management but also reveals the potential for genetic studies to shed light upon long-standing questions pertaining to the history and fate of natural populations.


2015 ◽  
Vol 106 (S1) ◽  
pp. 459-468 ◽  
Author(s):  
Susana González ◽  
Mariana Cosse ◽  
María del Rosario Franco ◽  
Louise Emmons ◽  
Carly Vynne ◽  
...  

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