scholarly journals Genetic population structure of Gyrodactylus thymalli (Monogenea) in a large Norwegian river system

Parasitology ◽  
2015 ◽  
Vol 142 (14) ◽  
pp. 1693-1702 ◽  
Author(s):  
RUBEN ALEXANDER PETTERSEN ◽  
TOR ATLE MO ◽  
HAAKON HANSEN ◽  
LEIF ASBJØRN VØLLESTAD
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Gene Flow ◽  
Haplotype Diversity ◽  
River System ◽  
Genetic Population Structure ◽  
Restricted Gene Flow ◽  
Upstream Migration ◽  
Genetic Population ◽  
Long Time

SUMMARYThe extent of geographic genetic variation is the result of several processes such as mutation, gene flow, selection and drift. Processes that structure the populations of parasite species are often directly linked to the processes that influence the host. Here, we investigate the genetic population structure of the ectoparasite Gyrodactylus thymalli Žitňan, 1960 (Monogenea) collected from grayling (Thymallus thymallus L.) throughout the river Glomma, the largest watercourse in Norway. Parts of the mitochondrial dehydrogenase subunit 5 (NADH 5) and cytochrome oxidase I (COI) genes from 309 G. thymalli were analysed to study the genetic variation and investigated the geographical distribution of parasite haplotypes. Three main clusters of haplotypes dominated the three distinct geographic parts of the river system; one cluster dominated in the western main stem of the river, one in the eastern and one in the lower part. There was a positive correlation between pairwise genetic distance and hydrographic distance. The results indicate restricted gene flow between sub-populations of G. thymalli, most likely due to barriers that limit upstream migration of infected grayling. More than 80% of the populations had private haplotypes, also indicating long-time isolation of sub-populations. According to a molecular clock calibration, much of the haplotype diversity of G. thymalli in the river Glomma has developed after the last glaciation.

scholarly journals Genetic population structure of mangrove jack, Lutjanus argentimaculatus (Forsskål)

2003 ◽  
Vol 54 (2) ◽  
pp. 127 ◽  
Author(s):  
Jennifer R. Ovenden ◽  
Raewyn Street
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Allelic Variation ◽  
Gene Diversity ◽  
Haplotype Diversity ◽  
Genetic Population Structure ◽  
Western Coast ◽  
Base Pairs ◽  
Genetic Population ◽  
Lutjanus Argentimaculatus

Translocations of mangrove jack, Lutjanus argentimaculatus (Forsskål 1775), to increase angling opportunities in artificial impoundments are foreshadowed in Queensland. To evaluate genetic population structure before translocations occur, mangrove jack were collected from three sites on the Queensland coast and from one site on the north-western coast of Western Australia. Allelic variation at four dinucleotide microsatellite loci was high: gene diversity (heterozygosity) ranged from 0.602 to 0.930 and allelic counts from 10 to 24. Genetic differentiation among collection sites was weak: estimates of FST were 0.002 for all four sites, and less (FST = 0.001) across a major biogeographical boundary (the Torres Strait region). Nucleotide sequence from two mitochondrial regions (control, 375 base pairs, and ATPase, 415 base pairs) was obtained from a subset of the Australian and additional Indo-Pacific (Indonesian and Samoan) mangrove jack. Haplotype diversity was high (control region, 33 haplotypes for 34 fish; ATPase region, 13 haplotypes for 56 fish). Phylogenetic analysis of mitochondrial DNA sequence data could not discern a relationship between tree topology and geography. These results suggest that mangrove jack in Queensland, and possibly throughout Australia, experience high levels of gene flow. The artificial gene flow caused by permitted translocations is unlikely to exceed natural levels. Fine-scale ecological matching between donor and recipient populations may increase stocking success, and is important if translocation is needed as a species recovery tool in the future.

Genetic population structure of the fairy shrimp Branchinecta coloradensis (Anostraca) in the Rocky Mountains of Colorado

1998 ◽  
Vol 76 (11) ◽  
pp. 2049-2057 ◽  
Author(s):  
Andrew J Bohonak
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Rocky Mountains ◽  
Regional Scale ◽  
Local Scale ◽  
Genetic Population Structure ◽  
Fairy Shrimp ◽  
Genetic Population ◽  
Contemporary Gene Flow ◽  
Branchinecta Coloradensis

Dispersal rates for freshwater invertebrates are often inferred from population genetic data. Although genetic approaches can indicate the amount of isolation in natural populations, departures from an equilibrium between drift and gene flow often lead to biased gene flow estimates. I investigated the genetic population structure of the pond-dwelling fairy shrimp Branchinecta coloradensis in the Rocky Mountains of Colorado, U.S.A., using allozymes. Glaciation in this area and the availability of direct dispersal estimates from previous work permit inferences regarding the relative impacts of history and contemporary gene flow on population structure. Hierarchical F statistics were used to quantify differentiation within and between valleys (thetaSV and thetaVT, respectively). Between valleys separated by 5-10 km, a high degree of differentiation (thetaVT = 0.77) corresponds to biologically reasonable gene flow estimates of 0.07 individuals per generation, although it is possible that this value represents founder effects and nonequilibrium conditions. On a local scale (<=110 m), populations are genetically similar (thetaSV = 0.13) and gene flow is estimated to be 1.7 individuals exchanged between ponds each generation. This is very close to an ecological estimate of dispersal for B. coloradensis via salamanders. Gene flow estimates from previous studies on other Anostraca are also similar on comparable geographic scales. Thus, population structure in B. coloradensis appears to be at or near equilibrium on a local scale, and possibly on a regional scale as well.

scholarly journals Genetic population structure of the blue sea star Linckia laevigata in the Visayas (Philippines)

2015 ◽  
pp. 1-7 ◽  
Author(s):  
Diana Sr Alcazar ◽  
Marc Kochzius
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Gene Flow ◽  
Comparative Analysis ◽  
Marine Invertebrates ◽  
Genetic Population Structure ◽  
Sea Star ◽  
Genetic Population ◽  
Gene Coi ◽  
Linckia Laevigata

Coral reef associated marine invertebrates, such as the blue sea starLinckia laevigata, have a life history with two phases: sedentary adults and planktonic larvae. On the one hand it is hypothesised that the long pelagic larval duration facilitates large distance dispersal. On the other hand, complex oceanographic and geographic characteristics of the Visayan seascape could cause isolation of populations. The study aims to investigate the genetic diversity, genetic population structure and gene flow inL. laevigatato reveal connectivity among populations in the Visayas. The analysis is based on partial sequences (626 bp in length) of the mitochondrial cytochrome oxidase I gene (COI) from 124 individuals collected from five localities in the Visayas. A comparative analysis of these populations with populations from the Indo-Malay Archipelago (IMA) published previously is also presented. Genetic diversity was high (h = 0.98, π = 1.6%) and comparable with preceding studies. Analyses of molecular variance (AMOVA) revealed a lack of spatial population differentiation among sample sites in the Visayas (ΦST-value = 0.009;P &gt; 0.05). The lack of genetic population structure indicates high gene flow among populations ofL. laevigatain the Visayas. Comparative analysis with data from the previous study indicates high connectivity of the Visayas with the central part of the IMA.

scholarly journals Phylogeography of Hyalomma (Euhyalomma) lusitanicum (Acarina, Parasitiformes, Ixodidae) in Andalusia based on mitochondrial cytochrome oxidase I gene

2021 ◽  
Author(s):  
Francisco J. Márquez ◽  
Antonio Caruz
Keyword(s):  
Population Structure ◽  
Iberian Peninsula ◽  
Cytochrome Oxidase ◽  
Canary Island ◽  
Sequence Data ◽  
Haplotype Diversity ◽  
Genetic Population Structure ◽  
Coi Gene ◽  
Genetic Population ◽  
Mtdna Sequence

AbstractThe genetic population structure relationships of Hyalomma (Euhyalomma) lusitanicum in Andalusia (the south of the Iberian Peninsula) were examined using mtDNA sequence data from 887 bp of cytochrome oxidase subunit I (COI) gene. The sequence for the COI region was determined for 84 individuals collected in several localities of Andalusia, and 10 for other localities (i.e., five from Toledo, central Iberian Peninsula, four from Sicily (Italy) and one from Canary Island). Seventeen haplotypes were detected, including 27 polymorphic sites. The number of amino acid substitutions per site from mean diversity calculations for the entire population was 0.017. AMOVA analysis revealed a low gene flow that characterises the genetic population structure of this species in South Iberian Peninsula, with a haplotype diversity (h) value of 0.815. No geographically induced differentiation was observed, and separate evolutionary units were not detected. Our results indicate low genetic diversity across the geographical range of H. lusitanicum tick in Andalusia. Our data do not show any genetic discontinuity between the tick populations studied, including specimens from Canary Island and Sicily (Italy).

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