Search results for "Gene Flow"
showing 10 items of 177 documents
Evolutionary significance of the invasion of introduced populations into the native range of Meconopsis cambrica
2011
The long history of the deliberate or accidental and human-mediated dispersal of flowering plants has led to the introduction of foreign genotypes of many species into areas of Europe hitherto occupied by potentially distinct native populations. Studies of the genetic and evolutionary consequences of such changes are handicapped by the difficulty of identifying the surviving native populations of many species in the absence of clear morphological differences. We investigated the relationship between putative native and introduced populations of the herbaceous perennial Meconopsis cambrica (Papaveraceae), as the isolated native populations of this species can be identified by historical and …
Cryptic microgeographic variation in responses of larval Atlantic cod to warmer temperatures
2021
AbstractAlthough temperature is known to drive species dynamics and distributions, our understanding of the extent to which thermal plasticity varies within species is poor. Differences in plasticity can arise through local adaptation to heterogeneous environments, hybridization, and the release of cryptic genetic variation in novel environments. Here, wild Atlantic cod (Gadus morhua) from contrasting environments inside and outside of a fjord system in southern Norway spawned freely in a semi-natural laboratory environment, generating pure crosses and reciprocal hybrids. A common-garden rearing experiment of the larvae at 6°C, 9.5°C, and 13°C revealed cryptic genetic variation in thermal r…
The genetic heritage of Alpine local cattle breeds using genomic SNP data
2020
Abstract Background Assessment of genetic diversity and population structure provides important control metrics to avoid genetic erosion, inbreeding depression and crossbreeding between exotic and locally-adapted cattle breeds since these events can have deleterious consequences and eventually lead to extinction. Historically, the Alpine Arc represents an important pocket of cattle biodiversity with a large number of autochthonous breeds that provide a fundamental source of income for the entire regional economy. By using genotype data from medium-density single nucleotide polymorphism (SNP) arrays, we performed a genome-wide comparative study of 23 cattle populations from the Alpine Arc an…
Adaptation to a seasonally varying environment: a strong latitudinal cline in reproductive diapause combined with high gene flow in Drosophila montana
2011
Adaptation to seasonal changes in the northern hemisphere includes an ability to predict the forthcoming cold season from gradual changes in environmental cues early enough to prepare for the harsh winter conditions. The magnitude and speed of changes in these cues vary between the latitudes, which induces strong selection pressures for local adaptation. We studied adaptation to seasonal changes in Drosophila montana, a northern maltfly, by defining the photoperiodic conditions leading to adult reproductive diapause along a latitudinal cline in Finland and by measuring genetic differentiation and the amount of gene flow between the sampling sites with microsatellites. Our data revealed a cl…
Opposing health effects of hybridization for conservation
2021
The continuing decline of many natural plant and animal populations emphasizes the importance of conservation strategies. Hybridization as a management tool has proven successful in introducing gene flow to small, inbred populations, but can be also associated with health risks. For example, hybridization can change susceptibility to infection in either direction due to heterosis (hybrid vigor) and outbreeding depression, but such health effects have rarely been considered in the genetic management of populations. Here, we investigated the effects of experimental outcrossing between the critically endangered Saimaa landlocked salmon (Salmo salar m. sebago) and the genetically more diverse A…
Who threatens who? Natural hybridization between Lotus dorycnium and the island endemic Lotus fulgurans (Fabaceae)
2010
In contrast to its creative role in plant evolution, hybridization may be a cause for concern in efforts to preserve rare and endangered species. Threats can be more acute when population sizes are unequal and when barriers to introgression are weak. Lotus fulgurans is an endangered Balearic Islands endemic shrub related to the widespread Mediterranean species Lotus dorycnium. Both species are morphologically distinct when they grow together. However, morphologically intermediate individuals have been observed on the island of Minorca, in a single, narrowly localized, and apparently stable hybrid zone. Morphological and molecular markers suggest that gene flow between these two Lotus specie…
Influences of geographic differentiation in the forewing warning signal of the wood tiger moth in Alaska
2014
Aposematic organisms have warning signals advertising their unpalatability to predators, and because signal efficiency is better in higher densities, positive frequency-dependent selection is expected to select against less common signals. The wood tiger moth (Parasemia plantaginis) occurs across the Holarctic and its conspicuous hindwings serve as warning signals to predators. It also has conspicuous black and white forewing patterns that could act as warning signals, or help to hide the moth by preventing predators from seeing the outline of the moth’s body (a strategy known as disruptive coloration). In Alaska, the predominant forewing pattern changes distinctly between the regions aroun…
Highly asymmetric fine-scale genetic structure between sexes of African striped mice and indication for condition dependent alternative male dispersa…
2011
Sex-biased dispersal is observed in many taxa, but few studies have compared sex-biased dispersal among and within populations. We addressed the magnitude and habitat dependency of sex-biased dispersal in social African striped mice by separating group-related from population-related genetic variance to understand the contribution of each sex to deme structure. As dispersal over unoccupied habitat is likely to be more costly than dispersal within a population, we predicted that individuals leaving the natal population have a lower body condition, being inferior to heavier territorial individuals. Fine-scale genetic structure was detected in both sexes. Female relatedness decreased continuou…
The voyage of an invasive species across continents: genetic diversity of North American and European Colorado potato beetle populations
2005
The paradox of successful invading species is that they are likely to be genetically depauperate compared to their source population. This study on Colorado potato beetles is one of the few studies of the genetic consequences of continent-scale invasion in an insect pest. Understanding gene flow, population structure and the potential for rapid evolution in native and invasive populations offers insights both into the dynamics of small populations that become successful invaders and for their management as pests. We used this approach to investigate the invasion of the Colorado potato beetle (Leptinotarsa decemlineata) from North America to Europe. The beetles invaded Europe at the beginnin…
Analysis of gene flow and habitat patch network for Chazara briseis (Lepidoptera: Satyridae) in an agricultural landscape
1997
Abstract A fine geographic-scale population genetic structure analysis was performed for the endangered butterfly species Chazara briseis in the region of Halle an der Saale, Germany, for the investigation of gene flow and possible effects of habitat fragmentation on genetic variability. Patterns of genetic variance were estimated by allozyme electrophoresis and quantified with F -statistics. Levels of genetic variation were high, expected heterozygosity H e = 0.20, and mean number of alleles per locus, A = 1.93, indicating large population sizes. Butterflies inhabiting the study area probably constituted just one population and the fragmented nature of the habitat patches did not substanti…