Search results for "population structure"
showing 10 items of 67 documents
Phylogeographic patterns of decapod crustaceans at the Atlantic-Mediterranean transition.
2012
9 páginas, 4 figuras, 3 tablas.
The Pillars of Hercules as a bathymetric barrier to gene flow promoting isolation in a global deep-sea shark (Centroscymnus coelolepis).
2015
Catarino, Diana ... et. al.-- 19 pages, 5 figures, 4 tables, data accessibility http://dx.doi.org/10.5061/dryad.ss368, supporting information http://dx.doi.org/10.1111/mec.13453
Population structure in the Méditerranean basin: a Y chromosome perspective
2006
The Mediterranean region has been characterised by a number of pre-historical and historical demographic events whose legacy on the current genetic landscape is still a matter of debate. In order to investigate the degree of population structure across the Mediterranean, we have investigated Y chromosome variation in a large dataset of Mediterranean populations, 11 of which are first described here. Our analyses identify four main clusters in the Mediterranean that can be labelled as North Africa, Arab, Central-East and West Mediterranean. In particular, Near Eastern samples tend to separate according to the presence of Arab Y chromosome lineages, suggesting that the Arab expansion played a…
Allozyme Similarity in Two Morphologically Distinguishable Populations ofParacentrotus Lividus(Echinodermata) From Distinct Areas of the Mediterranea…
1998
Allozymes ofParacentrotus lividusfrom Palermo Gulf in the northern Sicilian coast (Italy) and from a small body-size population in the western Greek coast (Ionian Sea) were investigated by PAGE. Five of the twenty examined loci were polymorphic(AAT*, ADH*, ME*, PGI*andPGM*)over each population with a polymorphism value of 0–25. Average heterozygosity was equal to 0081 in the Sicilian sample and 0084 in the Greek. Deviations from Hardy-Weinberg equilibrium were significant inME*andPGI*loci (as calculated byy).Nei's (1978) genetic distance (D=0–0025) index described a close identity between the two samples. FSTvalue of polymorphic loci ranged from 0001 to 0029, its mean value (0–008) resultin…
Recent expansion of Northeast Atlantic and Mediterranean populations of Melicertus (Penaeus) kerathurus (Crustacea: Decapoda).
2009
We analysed the genetic diversity of Melicertus kerathurus (Penaeidae), a commercially valuable penaeid shrimp that is distributed in the Mediterranean Sea and eastern Atlantic Ocean. We examined the polymorphism of a 494 bp DNA segment of the mitochondrial COI region in 173 individuals, sampled in nine Mediterranean and two Atlantic samples, covering the whole range of the species from the tropical waters of the Gulf of Guinea to the eastern part of the Mediterranean Sea. The mean nucleotide and haplotype diversities were π = 0.00275 and h = 0.718, respectively, for the global data set, with the highest values occurring in the African samples and the lowest in the Adriatic Sea. A clear sam…
Recombination in viruses: Mechanisms, methods of study, and evolutionary consequences
2014
© 2014 Elsevier B.V. Recombination is a pervasive process generating diversity in most viruses. It joins variants that arise independently within the same molecule, creating new opportunities for viruses to overcome selective pressures and to adapt to new environments and hosts. Consequently, the analysis of viral recombination attracts the interest of clinicians, epidemiologists, molecular biologists and evolutionary biologists. In this review we present an overview of three major areas related to viral recombination: (i) the molecular mechanisms that underlie recombination in model viruses, including DNA-viruses (Herpesvirus) and RNA-viruses (Human Influenza Virus and Human Immunodeficien…
Impact of landscape on spatial genetic structure and diversity ofCoenagrion mercuriale(Zygoptera:Coenagrionidae) in northern France
2015
AbstractLoss and fragmentation of habitat is a current main cause of biodiversity loss in freshwater habitats. Odonates (dragonflies and damselflies) depend on these habitats to complete their development. Fragmentation may be a particular threat for odonates because it generates a network of small habitat patches within which populations could suffer from isolation and loss of genetic diversity. The southern damselfly Coenagrion mercuriale is categorized on the IUCN red list as Near Threatened, largely because of population fragmentation and demographic declines associated with changes in land use. Small populations at the margin of this species’ range are of particular concern because the…
Habitat effects on population connectivity in a coastal seascape
2014
Published version of an article from: Marine Ecology Progress Series. Also available from Inter Research: http://dx.doi.org/10.3354/meps10944 Knowing how population connectivity varies across heterogeneous habitats can provide insight into the mechanisms underlying population structuring, and ultimately help to inform conservation and management actions. We studied whether the spatial extent of connectivity in coastal Atlantic cod Gadus morhua varied with coastal topography, hypothesizing that connectivity during all life stages would be greater among open, exposed habitats compared to sheltered, fjord-like habitats. We tested this hypothesis using (1) an extensive mark-recapture data set t…
Genetic population structure of Epinephelus marginatus (Pisces, Serranidae) revealed by two molecular markers
2006
In this paper, data are presented regarding the population structure of dusky grouper (Epinephelus marginatus) which was sampled in the Mediterranean Sea and Atlantic Ocean using two different molecular markers, ND2 RFLP and cytochrome b (cyt b) sequence analysis. The main objective of the study is to analyse the genetic variability of E. marginatus in the Mediterranean Sea to define how the biological characteristics of the species, such as the dispersal capability of pelagic larvae and the benthonic-sedentary life style, can affect the genetic population structure or maintaining the gene flow or determining genetic differences. Furthermore, we considered an Atlantic sample to establish th…
Genetic structure and assignment test in five sheep breeds reared in Sicily using microsatellites
2011
A total of 331 individuals from five sheep breeds reared in Sicily (Barbaresca (BAR, n=57), Comisana (COM, n=65), Pinzirita (PIN, n=75), Sarda (SAR, n=64), and Valle del Belice (VdB, n=70)) were analysed to investigate genetic structure and perform an assignment test. A panel of 20 microsatellite markers was used, and a total of 259 alleles were observed. The polymorphic information content (PIC) all over loci was equal to 0.757, showing that the microsatellites panel used was highly informative. Estimates of observed heterozygosity ranged from 0.655 in the BAR breed to 0.751 in the COM breed. The low value of genetic differentiation among breeds (FST=0.048) may indicate that these breeds a…