Search results for "Biological dispersal"
showing 10 items of 326 documents
Low levels of relatedness on black grouse leks despite male philopatry
2008
In lekking species, males cluster on specific areas for display (the leks) and females generally prefer to copulate with males on large aggregations. The maintenance of leks in which only a few males reproduce might be explained if subordinate males gain indirect fitness benefits. By joining a lek on which relatives are displaying, subordinates might attract more females to the lek thereby increasing the mating opportunities of their kin. In black grouse, a genetic structure among leks has previously been found suggesting that relatives could display together. Using 11 microsatellite loci, we extended this result by testing for the presence of kin structures in nine black grouse leks (101 m…
Hybridization between mouse lemurs in an ecological transition zone in southern Madagascar
2009
Hybrid zones in ecotones can be useful model systems for the study of evolutionary processes that shape the distribution and discreteness of species. Such studies could be important for an improved understanding of the complex biogeography of Madagascar, which is renowned for its outstanding degree of small-scale endemism. Certain forest remnants in central Madagascar indicate that transitional corridors across the island could have connected microendemics in different forest types in the past. Evolutionary processes in such corridors are difficult to study because most of these corridors have disappeared due to deforestation in central Madagascar. We studied a hybrid zone in one of the few…
Effects of population outcrossing on rotifer fitness
2010
Abstract Background Outcrossing between populations can exert either positive or negative effects on offspring fitness. Cyclically parthenogenetic rotifers, like other continental zooplankters, show high genetic differentiation despite their high potential for passive dispersal. Within this context, the effects of outcrossing may be relevant in modulating gene flow between populations through selection for or against interpopulation hybrids. Nevertheless, these effects remain practically unexplored in rotifers. Here, the consequences of outcrossing on the rotifer Brachionus plicatilis were investigated. Cross-mating experiments were performed between a reference population and three alterna…
Polymorphism in Developmental Mode and Its Effect on Population Genetic Structure of a Spionid Polychaete, Pygospio elegans
2012
Population genetic structure of sedentary marine species is expected to be shaped mainly by the dispersal ability of their larvae. Long-lived planktonic larvae can connect populations through migration and gene flow, whereas species with nondispersive benthic or direct-developing larvae are expected to have genetically differentiated populations. Poecilogonous species producing different larval types are ideal when studying the effect of developmental mode on population genetic structure and connectivity. In the spionid polychaete Pygospio elegans, different larval types have been observed between, and sometimes also within, populations. We used microsatellite markers to study population st…
Why Africa matters: evolution of Old World Salvia (Lamiaceae) in Africa
2014
BACKGROUND AND AIMS Salvia is the largest genus in Lamiaceae and it has recently been found to be non-monophyletic. Molecular data on Old World Salvia are largely lacking. In this study, we present data concerning Salvia in Africa. The focus is on the colonization of the continent, character evolution and the switch of pollination systems in the genus. METHODS Maximum likelihood and Bayesian inference were used for phylogenetic reconstruction. Analyses were based on two nuclear markers [internal transcribed spacer (ITS) and external transcribed spacer (ETS)] and one plastid marker (rpl32-trnL). Sequence data were generated for 41 of the 62 African taxa (66 %). Mesquite was used to reconstru…
The colonization history of Olea europaea L. in Macaronesia based on internal transcribed spacer 1 (ITS-1) sequences, randomly amplified polymorphic …
2000
Phylogenetic relationships in the Olea europaea complex and the phylogeography of 24 populations of the Macaronesian olive (O. europaea ssp. cerasiformis) were assessed by using three molecular markers: nuclear ribosomal internal transcribed spacer 1 (ITS-1) sequences, randomly amplified polymorphic DNAs (RAPD), and intersimple sequence repeats (ISSR). Parsimony analysis of the ITS-1 sequences and Neighbour-joining (NJ) analyses of RAPD and ISSR banding variation revealed four major lineages in the O. europaea complex: (1) ssp. cuspidata; (2) ssp. cerasiformis from Madeira; (3) ssp. laperrinei; and (4) ssp. cerasiformis from the Canary Islands plus ssp. europaea. These results provide unequ…
The origin of the serpentine endemic Minuartia laricifolia subsp. ophiolitica by vicariance and competitive exclusion.
2013
Serpentine soils harbour a unique flora that is rich in endemics. We examined the evolution of serpentine endemism in Minuartia laricifolia, which has two ecologically distinct subspecies with disjunct distributions: subsp. laricifolia on siliceous rocks in the western Alps and eastern Pyrenees and subsp. ophiolitica on serpentine in the northern Apennines. We analysed AFLPs and chloroplast sequences from 30 populations to examine their relationships and how their current distributions and ecologies were influenced by Quaternary climatic changes. Minuartia laricifolia was divided into four groups with a BAPS cluster analysis of the AFLP data, one group consisted only of subsp. ophiolitica, …
Does genetic population structure of Ambrosina bassii L. (Araceae, Ambrosineae) attest a post-Messinian land-bridge between Sicily and Africa?
2012
Abstract Aim of the present work is the analysis (through the study of enzyme polymorphism) of Sicilian and African (Tunisian) populations of Ambrosina bassii , a small perennial endemic to the Central-Western Mediterranean basin, in order to verify if the complex geological history of this part of the Mediterranean area left its mark in the present-day genetic structure of this taxon. Starch gel allozyme electrophoresis of seven putative loci of A. bassii was employed to estimate genetic diversity, genetic structure and gene flow. Populations from Sicily, Tunisia and Sardinia (as outgroup) were sampled. Results show that Sicily populations have 4 private alleles, Sardinia 3, Tunisia just o…
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…
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…