scholarly journals Do Mediterranean crickets Gryllus bimaculatus De Geer (Orthoptera: Gryllidae) come from the Mediterranean? Largescale phylogeography and regional gene flow

2009 ◽  
Vol 100 (1) ◽  
pp. 49-58 ◽  
Author(s):  
M. Ferreira ◽  
J.W.H. Ferguson
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
South African ◽  
Population Genetic ◽  
Genetic Differences ◽  
Field Cricket ◽  
Gryllus Bimaculatus ◽  
Population Genetic Differentiation ◽  
The Mediterranean

AbstractWe investigate the degree of between-population genetic differentiation in the Mediterranean field cricket Gryllus bimaculatus, as well as the possible causes of such differentiation. Using cytochrome b mtDNA sequences, we estimate genetic variation in G. bimaculatus from seven South African and two Mediterranean populations. Within-population genetic variation in Europe (two haplotypes, one unique to a single individual) suggest low effective population size and strong bottlenecks with associated founder effects, probably due to cold winter environments in Europe that limit reproduction to a short part of the summer. The likely cause for this is the daily maxima in winter temperatures that fall below the critical level of 16°C (enabling normal calling and courtship behaviour) in Mediterranean Europe, whereas the equivalent temperatures in southern Africa are above this limit and enable reproduction over a large part of the year. European genetic variants were either shared with Africa or closely related to African haplotypes. For survival, European populations are probably dependent on immigration from other areas, including Africa. South African populations have low but measurable gene flow with Europe and show significant between-population genetic differentiation (30 haplotypes). Isolation-by-distance is not sufficient to explain the degree of between-population genetic differences observed, and a large degree of dispersal is also required in order to account for the observed patterns. Differences in morphology and calling behaviour among these populations are underlied by these genetic differences.

scholarly journals Geography is more important than life history in the recent diversification of the tiger salamander complex

2021 ◽  
Vol 118 (17) ◽  
pp. e2014719118
Author(s):  
Kathryn M. Everson ◽  
Levi N. Gray ◽  
Angela G. Jones ◽  
Nicolette M. Lawrence ◽  
Mary E. Foley ◽  
...  
Keyword(s):  
Life History ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Population Genetic ◽  
Tiger Salamander ◽  
Life History Variation ◽  
Mexican Axolotl ◽  
Population Genetic Differentiation ◽  
Wide Range ◽  
Lineage Divergence

The North American tiger salamander species complex, including its best-known species, the Mexican axolotl, has long been a source of biological fascination. The complex exhibits a wide range of variation in developmental life history strategies, including populations and individuals that undergo metamorphosis; those able to forego metamorphosis and retain a larval, aquatic lifestyle (i.e., paedomorphosis); and those that do both. The evolution of a paedomorphic life history state is thought to lead to increased population genetic differentiation and ultimately reproductive isolation and speciation, but the degree to which it has shaped population- and species-level divergence is poorly understood. Using a large multilocus dataset from hundreds of samples across North America, we identified genetic clusters across the geographic range of the tiger salamander complex. These clusters often contain a mixture of paedomorphic and metamorphic taxa, indicating that geographic isolation has played a larger role in lineage divergence than paedomorphosis in this system. This conclusion is bolstered by geography-informed analyses indicating no effect of life history strategy on population genetic differentiation and by model-based population genetic analyses demonstrating gene flow between adjacent metamorphic and paedomorphic populations. This fine-scale genetic perspective on life history variation establishes a framework for understanding how plasticity, local adaptation, and gene flow contribute to lineage divergence. Many members of the tiger salamander complex are endangered, and the Mexican axolotl is an important model system in regenerative and biomedical research. Our results chart a course for more informed use of these taxa in experimental, ecological, and conservation research.

Comparative host–parasite population genetic structures: obligate fly ectoparasites on Galapagos seabirds

Parasitology ◽  
2013 ◽  
Vol 140 (9) ◽  
pp. 1061-1069 ◽  
Author(s):  
IRIS I. LEVIN ◽  
PATRICIA G. PARKER
Keyword(s):  
Gene Flow ◽  
Genetic Differentiation ◽  
Population Genetic ◽  
Sequence Data ◽  
Population Genetic Study ◽  
Haemosporidian Parasite ◽  
Dna Sequence Data ◽  
Sula Granti ◽  
Breeding Attempt ◽  
Genetic Structures

SUMMARYParasites often have shorter generation times and, in some cases, faster mutation rates than their hosts, which can lead to greater population differentiation in the parasite relative to the host. Here we present a population genetic study of two ectoparasitic flies, Olfersia spinifera and Olfersia aenescens compared with their respective bird hosts, great frigatebirds (Fregata minor) and Nazca boobies (Sula granti). Olfersia spinifera is the vector of a haemosporidian parasite, Haemoproteus iwa, which infects frigatebirds throughout their range. Interestingly, there is no genetic differentiation in the haemosporidian parasite across this range despite strong genetic differentiation between Galapagos frigatebirds and their non-Galapagos conspecifics. It is possible that the broad distribution of this one H. iwa lineage could be facilitated by movement of infected O. spinifera. Therefore, we predicted more gene flow in both fly species compared with the bird hosts. Mitochondrial DNA sequence data from three genes per species indicated that despite marked differences in the genetic structure of the bird hosts, gene flow was very high in both fly species. A likely explanation involves non-breeding movements of hosts, including movement of juveniles, and movement by adult birds whose breeding attempt has failed, although we cannot rule out the possibility that closely related host species may be involved.

scholarly journals Elucidating the drivers of genetic differentiation in Malaysian torrent frogs (Anura: Ranidae: Amolops): a landscape genomics approach

2019 ◽  
Vol 190 (1) ◽  
pp. 65-78 ◽  
Author(s):  
Kin Onn Chan ◽  
Rafe M Brown
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Isolation By Distance ◽  
Variance Partitioning ◽  
Nucleotide Polymorphisms ◽  
Landscape Genomics ◽  
Mountain Ranges ◽  
Historical Factors ◽  
Environmental Attributes

Abstract The interplay between environmental attributes and evolutionary processes can provide valuable insights into how biodiversity is generated, partitioned and distributed. This study investigates the role of spatial, environmental and historical factors that could potentially drive diversification and shape genetic variation in Malaysian torrent frogs. Torrent frogs are ecologically conserved, and we hypothesize that this could impose tight constraints on dispersal routes, gene flow and consequently genetic structure. Moreover, levels of gene flow were shown to vary among populations from separate mountain ranges, indicating that genetic differentiation could be influenced by landscape features. Using genome-wide single nucleotide polymorphisms, in conjunction with landscape variables derived from Geographic Information Systems, we performed distance-based redundancy analyses and variance partitioning to disentangle the effects of isolation-by-distance (IBD), isolation-by-resistance (IBR) and isolation-by-colonization (IBC). Our results demonstrated that IBR contributed minimally to genetic variation. Intraspecific population structure can be largely attributed to IBD, whereas interspecific diversification was primarily driven by IBC. We also detected two distinct population bottlenecks, indicating that speciation events were likely driven by vicariance or founder events.

scholarly journals Spatial Structure and Genetic Variation of a Mangrove Species (Avicennia marina (Forssk.) Vierh) in the Farasan Archipelago

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1287
Author(s):  
Rahmah N. Al-Qthanin ◽  
Samah A. Alharbi
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Species Conservation ◽  
Natural Populations ◽  
Avicennia Marina ◽  
Conservation Strategies ◽  
Isolated Populations ◽  
Mangrove Species ◽  
Population Genetic Differentiation ◽  
Sea Currents

Avicennia marina (Forssk.) Vierh is distributed in patches along the Farasan archipelago coast and is the most common mangrove species in the Red Sea. However, to date, no studies have been directed towards understanding its genetic variation in the Farasan archipelago. In this investigation, genetic variations within and among natural populations of Avicennia marina in the Farasan archipelago were studied using 15 microsatellite markers. The study found 142 alleles on 15 loci in nine populations. The observed (Ho) and expected (He) heterozygosity values were 0.351 and 0.391, respectively, which are much lower than those of earlier studies on A. marina in the Arabian Gulf. An inbreeding effect from self-pollination might explain its heterozygote deficiency. Population genetic differentiation (FST = 0.301) was similar to other mangrove species. Our findings suggest that the sea current direction and coastal geomorphology might affect genetic dispersal of A. marina. The more isolated populations with fewer connections by sea currents exhibited lower genetic variation and differentiation between populations. The genetic clustering of populations fell into three main groups—Group 1 (populations of Farasan Alkabir Island), Group 2 (populations of Sajid Island), and Group 3 (mix of one population of Farasan Alkabir Island and a population of Zifaf Island). More genetic variation and less genetic differentiation occurred when the population was not isolated and had a direct connection with sea currents. Both of these factors contributed to limited propagule dispersal and produced significant structures among the population. It is expected that the results of this research will be useful in determining policy and species-conservation strategies and in the rehabilitation of A. marina mangrove stands on the Farasan islands in an effort to save this significant natural resource.

Sign in / Sign up

Export Citation Format

Share Document