6 research outputs found
The Evolutionary Dynamics of the Lion Panthera leo Revealed by Host and Viral Population Genomics
The lion Panthera leo is one of the world's most charismatic carnivores and is one of Africa's key predators. Here, we used a large dataset from 357 lions comprehending 1.13 megabases of sequence data and genotypes from 22 microsatellite loci to characterize its recent evolutionary history. Patterns of molecular genetic variation in multiple maternal (mtDNA), paternal (Y-chromosome), and biparental nuclear (nDNA) genetic markers were compared with patterns of sequence and subtype variation of the lion feline immunodeficiency virus (FIVPle), a lentivirus analogous to human immunodeficiency virus (HIV). In spite of the ability of lions to disperse long distances, patterns of lion genetic diversity suggest substantial population subdivision (mtDNA ΊSTâ=â0.92; nDNA FSTâ=â0.18), and reduced gene flow, which, along with large differences in sero-prevalence of six distinct FIVPle subtypes among lion populations, refute the hypothesis that African lions consist of a single panmictic population. Our results suggest that extant lion populations derive from several Pleistocene refugia in East and Southern Africa (âŒ324,000â169,000 years ago), which expanded during the Late Pleistocene (âŒ100,000 years ago) into Central and North Africa and into Asia. During the Pleistocene/Holocene transition (âŒ14,000â7,000 years), another expansion occurred from southern refugia northwards towards East Africa, causing population interbreeding. In particular, lion and FIVPle variation affirms that the large, well-studied lion population occupying the greater Serengeti Ecosystem is derived from three distinct populations that admixed recently
Suppression and azimuthal anisotropy of prompt and nonprompt J/psi production in PbPb collisions at root S-NN=2.76 TeV
The nuclear modification factor RAA and the azimuthal anisotropy coefficient v2 of prompt and nonprompt (i.e. those from decays of b hadrons) J/Ï mesons, measured from PbPb and pp collisions at sNNââââ=2.76 TeV at the LHC, are reported. The results are presented in several event centrality intervals and several kinematic regions, for transverse momenta pT>6.5 GeV/c and rapidity |y|<2.4 , extending down to pT=3 GeV/c in the 1.6<|y|<2.4 range. The v2 of prompt J/Ï is found to be nonzero, but with no strong dependence on centrality, rapidity, or pT over the full kinematic range studied. The measured v2 of nonprompt J/Ï is consistent with zero. The RAA of prompt J/Ï exhibits a suppression that increases from peripheral to central collisions but does not vary strongly as a function of either y or pT in the fiducial range. The nonprompt J/Ï RAA shows a suppression which becomes stronger as rapidity or pT increases. The v2 and RAA of open and hidden charm, and of open charm and beauty, are compared
Communication and Reproductive Biology of Tarantulas
Theraphosidae spiders (commonly known as tarantulas) comprise some of the largest known spiders. It is the most diverse family among Mygalomorphae and Theraphosinae, endemic to the Neotropics, is the richest subfamily. However, the knowledge on some aspects of their reproductive biology is still unknown. Usually, the sexual behavior of tarantulas has been considered as âsimple,â that is, males just walk searching for females and when they randomly find one, the mating should occur. This point of view is changing as the number of studies has grown during the last 20 years, suggesting that the sexual behavior of Theraphosidae is far from simple. Such complexity may be represented by specific searching and court- ship behavior of males and active roles of females, leading to an intricate intersexual communication before mating, the occurrence of male copulatory, and complex pat- terns of palpal insertions. This chapter describes the ways of communication of tarantulas mainly during the sexual encounters. The patterns of courtship and copu- lation of representatives of most subfamilies will be described based on a biblio- graphic review. Finally, some general strategies of mating and reproduction of tarantulas will be discussed and topics for future research are presented.Fil: Ferretti, Nelson Edgardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Centro de Recursos Naturales Renovables de la Zona SemiĂĄrida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona SemiĂĄrida; Argentin