Search results for "population genetic"
showing 10 items of 273 documents
Low diversity but high differentiation: the population genetics of Aglaope infausta (Zygaenidae: Lepidoptera)
2003
Aim Aglaope infausta is a thermophilous Zygaenid of Atlanto-Mediterranean origin, distributed in Portugal, Spain, France and north-western Italy reaching its north-eastern distribution limit in western Germany. The local, regional and inter-regional genetic structure of this species is studied in this analysis. Location and methods The allozymes of 456 individuals from 12 populations (11 from western Germany and one from southern Portugal) were studied by electrophoresis. Results Six of the 19 loci analysed were monomorphic. Genetic differentiation between populations was high (FST: 0.404), while the mean genetic diversity was low (He: 3.4%). Most (96.5%) of the genetic variance between p…
Genetic Diversity, Population Size, and Fitness in Central and Peripheral Populations of a Rare Plant Lychnis viscaria
1999
: Genetic diversity is expected to decrease in small and isolated populations as a consequence of bottlenecks, founder effects, inbreeding, and genetic drift. The genetics and ecology of the rare perennial plant Lychnis viscaria (Caryophyllaceae) were studied in both peripheral and central populations within its distribution area. We aimed to investigate the overall level of genetic diversity, its spatial distribution, and possible differences between peripheral and central populations by examining several populations with electrophoresis. Our results showed that the level of genetic diversity varied substantially among populations ( Hexp = 0.000–0.116) and that the total level of genetic …
Macro- and microgeographic genetic structure in an ant species with alternative reproductive tactics in sexuals
2011
The genetic structure of social insect populations is influenced by their social organization and dispersal modes. The ant Hypoponera opacior shows diverse reproductive behaviours with regular cycles of outbreeding via winged sexuals and inbreeding via within-nest mating wingless sexuals that reproduce by budding. This unusual life cycle should be reflected in the genetic population structure, and we studied this on different scales using microsatellites. On a macrogeographic scale, populations were considerably structured and migration rates within the Chiricahuas were higher than those in between mountain ranges. On a local scale, our analyses revealed population viscosity through depende…
Population Genetics, Parasitism, and Long-Term Population Dynamics of Microcebus murinus in Littoral Forest Fragments of South-Eastern Madagascar
2012
Habitat fragmentation is a major threat for lemur conservation, as it reduces population sizes to levels that are nonviable in the long term. Alternatively, isolated populations may have great importance for conservation, as some are well protected and some lemurs do well even in small areas. Hence, knowing which characteristics indicate a population under threat is of paramount importance for conservation action. We studied Microcebus murinus populations confined to forest fragments of different sizes and states of degradation in south-eastern Madagascar to investigate relationships between population size, population dynamics, genetic diversity of coding and noncoding DNA, and infection r…
Long‐distance dispersal vs vicariance: the origin and genetic diversity of alpine plants in the Spanish Sierra Nevada
2006
Here, we investigated the origin and genetic diversity of four alpine plant species co-occurring in the Spanish Sierra Nevada and other high mountains in south-western Europe by analysis of amplified fragment length polymorphisms (AFLPs). In Kernera saxatilis, Silene rupestris and Gentiana alpina we found intraspecific phylogroups corresponding to mountain regions as predicted by the vicariance hypothesis. Moreover, genetic distances between Sierra Nevada and Pyrenees populations were always higher than those between populations from the Pyrenees and the south-western Alps/Massif Central. This suggests successive disruption of gene exchange between mountain ranges as postglacial climatic wa…
Epigenetic Diversity of Clonal White Poplar (Populus alba L.) Populations: Could Methylation Support the Success of Vegetative Reproduction Strategy?
2015
The widespread poplar populations of Sardinia are vegetatively propagated and live in different natural environments forming large monoclonal stands. The main goals of the present study were: i) to investigate/measure the epigenetic diversity of the poplar populations by determining their DNA methylation status; ii) to assess if and how methylation status influences population clustering; iii) to shed light on the changes that occur in the epigenome of ramets of the same poplar clone. To these purposes, 83 white poplar trees were sampled at different locations on the island of Sardinia. Methylation sensitive amplified polymorphism analysis was carried out on the genomic DNA extracted from l…
Fixation of mutations at the VP1 gene of foot-and-mouth disease virus. Can quasispecies define a transient molecular clock?
1991
The number of nucleotide (nt) substitutions found in the VP1 gene (encoding viral capsid protein) between any two of 16 closely related isolates of foot-and-mouth disease virus (FMDV) has been quantified as a function of the time interval between isolations [Villaverde et al.,J. Mol. Biol. 204(1988)771-776]. One of them (isolate C-S12) includes some replacements found in isolates that preceded it and other replacements found in later isolates. The study has revealed alternating periods of rapid evolution and of relative genetic stability of VP1. During a defined period of acute disease, the rate of fixation of replacements at the VP1 coding segment was 6 × 10-3 substitutions per nt per year…
Mitochondrial DNA evolution in experimental populations of Drosophila subobscura.
1990
When two mitochondrial DNA (mtDNA) haplotypes of Drosophila subobscura compete in experimental populations with discrete generations, one or the other approaches fixation, depending on the nuclear background with which they are associated. The approach to fixation, however, is strongly dependent on the effective number of females in the population, Nf. Whether or not the ultimate fate of a given mtDNA haplotype is determined by random genetic drift depends on Nf as well as on the relative fitnesses. Our experimental results show that the mtDNA polymorphisms observed in natural populations are affected by interactions among nuclear polymorphisms, random genetic drift, and direct selection on…
The Stock Genetic Structure of Two Sparidae Species, Diplodus vulgaris and Lithognathus mormyrus, in the Mediterranean Sea.
2003
Abstract Polyacrilamide gel electrophoresis (PAGE) of allozymes was used to investigate the intraspecies genetic variation and the genetic stock structure of Diplodus vulgaris and Lithognathus mormyrus captured from eight localities in the Mediterranean Sea. Twenty-two and 20 putative enzyme-coding loci were examined, respectively, in D. vulgaris and L. mormyrus . Polymorphic loci at the 95% level were used to assess the allozyme variability in D. vulgaris ( AAT-2 ∗ , EST-1 ∗ , GLDH ∗ , PEPB-2 ∗ , PGI-2 ∗ , PGM ∗ , SDH ∗ ) and L. mormyrus ( AAT-2 ∗ , EST-1 ∗ , GLDH ∗ , MDH-2 ∗ , PGI-2 ∗ , PGM ∗ ). The proportion of polymorphic loci in both species ranged from 0.31 ( D. vulgaris ) to 0.30 ( …
Isolation of seven polymorphic microsatellites in Ophioblennius atlanticus atlanticus (Perciformes, Blenniidae)
2005
We isolated and characterized seven polymorphic microsatellite loci of Ophioblennius atlanticus atlanticus (Valenciennes, 1836) using an optimized protocol to construct and screen a microsatellite-enriched genomic library. The analysis of variability was performed in 16 specimens from Faial Island (Azores, Portugal). The mean number of alleles was 8.71 ± ± ± 2.43 and the level of expected heterozygosity ranged from 0.764 to 0.903. The total exclusionary probabilities using these loci for the first and the second parent were 0.985 and 0.998, respectively, suggesting that these microsatellites are a useful tool for large-scale parentage analysis.